what is citations in research paper

Citing sources: Overview

• Citation style guides

Manage your references

Use these tools to help you organize and cite your references:

• Citation Management and Writing Tools

If you have questions after consulting this guide about how to cite, please contact your advisor/professor or the writing and communication center .

Why citing is important

It's important to cite sources you used in your research for several reasons:

• To show your reader you've done proper research by listing sources you used to get your information
• To be a responsible scholar by giving credit to other researchers and acknowledging their ideas
• To avoid plagiarism by quoting words and ideas used by other authors
• To allow your reader to track down the sources you used by citing them accurately in your paper by way of footnotes, a bibliography or reference list

About citations

Citing a source means that you show, within the body of your text, that you took words, ideas, figures, images, etc. from another place.

Citations are a short way to uniquely identify a published work (e.g. book, article, chapter, web site).  They are found in bibliographies and reference lists and are also collected in article and book databases.

Citations consist of standard elements, and contain all the information necessary to identify and track down publications, including:

• author name(s)
• titles of books, articles, and journals
• date of publication
• page numbers
• volume and issue numbers (for articles)

Citations may look different, depending on what is being cited and which style was used to create them. Choose an appropriate style guide for your needs.  Here is an example of an article citation using four different citation styles.  Notice the common elements as mentioned above:

Author - R. Langer

Article Title - New Methods of Drug Delivery

Source Title - Science

Volume and issue - Vol 249, issue 4976

Publication Date - 1990

Page numbers - 1527-1533

American Chemical Society (ACS) style:

Langer, R. New Methods of Drug Delivery. Science 1990 , 249 , 1527-1533.

IEEE Style:

R. Langer, " New Methods of Drug Delivery," Science , vol. 249 , pp. 1527-1533 , SEP 28, 1990 .

American Psychological Association   (APA) style:

Langer, R. (1990) . New methods of drug delivery. Science , 249 (4976), 1527-1533.

Modern Language Association (MLA) style:

Langer, R. " New Methods of Drug Delivery." Science 249.4976 (1990) : 1527-33.

What to cite

You must cite:

• Facts, figures, ideas, or other information that is not common knowledge

Publications that must be cited include:  books, book chapters, articles, web pages, theses, etc.

Another person's exact words should be quoted and cited to show proper credit 

When in doubt, be safe and cite your source!

Avoiding plagiarism

Plagiarism occurs when you borrow another's words (or ideas) and do not acknowledge that you have done so. In this culture, we consider our words and ideas intellectual property; like a car or any other possession, we believe our words belong to us and cannot be used without our permission.

Plagiarism is a very serious offense. If it is found that you have plagiarized -- deliberately or inadvertently -- you may face serious consequences. In some instances, plagiarism has meant that students have had to leave the institutions where they were studying.

The best way to avoid plagiarism is to cite your sources - both within the body of your paper and in a bibliography of sources you used at the end of your paper.

Some useful links about plagiarism:

• MIT Academic Integrity Overview on citing sources and avoiding plagiarism at MIT.
• Avoiding Plagiarism From the MIT Writing and Communication Center.
• Plagiarism: What It is and How to Recognize and Avoid It From Indiana University's Writing Tutorial Services.
• Plagiarism- Overview A resource from Purdue University.
• Next: Citation style guides >>
• Last Updated: Jan 16, 2024 7:02 AM
• URL: https://libguides.mit.edu/citing

• Privacy Policy

Buy Me a Coffee

Home » How to Cite Research Paper – All Formats and Examples

How to Cite Research Paper – All Formats and Examples

Table of Contents

Research Paper Citation

Research paper citation refers to the act of acknowledging and referencing a previously published work in a scholarly or academic paper . When citing sources, researchers provide information that allows readers to locate the original source, validate the claims or arguments made in the paper, and give credit to the original author(s) for their work.

The citation may include the author’s name, title of the publication, year of publication, publisher, and other relevant details that allow readers to trace the source of the information. Proper citation is a crucial component of academic writing, as it helps to ensure accuracy, credibility, and transparency in research.

How to Cite Research Paper

There are several formats that are used to cite a research paper. Follow the guide for the Citation of a Research Paper:

Last Name, First Name. Title of Book. Publisher, Year of Publication.

Example : Smith, John. The History of the World. Penguin Press, 2010.

Journal Article

Last Name, First Name. “Title of Article.” Title of Journal, vol. Volume Number, no. Issue Number, Year of Publication, pp. Page Numbers.

Example : Johnson, Emma. “The Effects of Climate Change on Agriculture.” Environmental Science Journal, vol. 10, no. 2, 2019, pp. 45-59.

Research Paper

Last Name, First Name. “Title of Paper.” Conference Name, Location, Date of Conference.

Example : Garcia, Maria. “The Importance of Early Childhood Education.” International Conference on Education, Paris, 5-7 June 2018.

Author’s Last Name, First Name. “Title of Webpage.” Website Title, Publisher, Date of Publication, URL.

Example : Smith, John. “The Benefits of Exercise.” Healthline, Healthline Media, 1 March 2022, https://www.healthline.com/health/benefits-of-exercise.

News Article

Last Name, First Name. “Title of Article.” Name of Newspaper, Date of Publication, URL.

Example : Robinson, Sarah. “Biden Announces New Climate Change Policies.” The New York Times, 22 Jan. 2021, https://www.nytimes.com/2021/01/22/climate/biden-climate-change-policies.html.

Author, A. A. (Year of publication). Title of book. Publisher.

Example: Smith, J. (2010). The History of the World. Penguin Press.

Author, A. A., Author, B. B., & Author, C. C. (Year of publication). Title of article. Title of Journal, volume number(issue number), page range.

Example: Johnson, E., Smith, K., & Lee, M. (2019). The Effects of Climate Change on Agriculture. Environmental Science Journal, 10(2), 45-59.

Author, A. A. (Year of publication). Title of paper. In Editor First Initial. Last Name (Ed.), Title of Conference Proceedings (page numbers). Publisher.

Example: Garcia, M. (2018). The Importance of Early Childhood Education. In J. Smith (Ed.), Proceedings from the International Conference on Education (pp. 60-75). Springer.

Author, A. A. (Year, Month Day of publication). Title of webpage. Website name. URL

Example: Smith, J. (2022, March 1). The Benefits of Exercise. Healthline. https://www.healthline.com/health/benefits-of-exercise

Author, A. A. (Year, Month Day of publication). Title of article. Newspaper name. URL.

Example: Robinson, S. (2021, January 22). Biden Announces New Climate Change Policies. The New York Times. https://www.nytimes.com/2021/01/22/climate/biden-climate-change-policies.html

Chicago/Turabian style

Please note that there are two main variations of the Chicago style: the author-date system and the notes and bibliography system. I will provide examples for both systems below.

Author-Date system:

• In-text citation: (Author Last Name Year, Page Number)
• Reference list: Author Last Name, First Name. Year. Title of Book. Place of publication: Publisher.
• In-text citation: (Smith 2005, 28)
• Reference list: Smith, John. 2005. The History of America. New York: Penguin Press.

Notes and Bibliography system:

• Footnote/Endnote citation: Author First Name Last Name, Title of Book (Place of publication: Publisher, Year), Page Number.
• Bibliography citation: Author Last Name, First Name. Title of Book. Place of publication: Publisher, Year.
• Footnote/Endnote citation: John Smith, The History of America (New York: Penguin Press, 2005), 28.
• Bibliography citation: Smith, John. The History of America. New York: Penguin Press, 2005.

JOURNAL ARTICLES:

• Reference list: Author Last Name, First Name. Year. “Article Title.” Journal Title Volume Number (Issue Number): Page Range.
• In-text citation: (Johnson 2010, 45)
• Reference list: Johnson, Mary. 2010. “The Impact of Social Media on Society.” Journal of Communication 60(2): 39-56.
• Footnote/Endnote citation: Author First Name Last Name, “Article Title,” Journal Title Volume Number, Issue Number (Year): Page Range.
• Bibliography citation: Author Last Name, First Name. “Article Title.” Journal Title Volume Number, Issue Number (Year): Page Range.
• Footnote/Endnote citation: Mary Johnson, “The Impact of Social Media on Society,” Journal of Communication 60, no. 2 (2010): 39-56.
• Bibliography citation: Johnson, Mary. “The Impact of Social Media on Society.” Journal of Communication 60, no. 2 (2010): 39-56.

RESEARCH PAPERS:

• Reference list: Author Last Name, First Name. Year. “Title of Paper.” Conference Proceedings Title, Location, Date. Publisher, Page Range.
• In-text citation: (Jones 2015, 12)
• Reference list: Jones, David. 2015. “The Effects of Climate Change on Agriculture.” Proceedings of the International Conference on Climate Change, Paris, France, June 1-3, 2015. Springer, 10-20.
• Footnote/Endnote citation: Author First Name Last Name, “Title of Paper,” Conference Proceedings Title, Location, Date (Place of publication: Publisher, Year), Page Range.
• Bibliography citation: Author Last Name, First Name. “Title of Paper.” Conference Proceedings Title, Location, Date. Place of publication: Publisher, Year.
• Footnote/Endnote citation: David Jones, “The Effects of Climate Change on Agriculture,” Proceedings of the International Conference on Climate Change, Paris, France, June 1-3, 2015 (New York: Springer, 10-20).
• Bibliography citation: Jones, David. “The Effects of Climate Change on Agriculture.” Proceedings of the International Conference on Climate Change, Paris, France, June 1-3, 2015. New York: Springer, 10-20.
• In-text citation: (Author Last Name Year)
• Reference list: Author Last Name, First Name. Year. “Title of Webpage.” Website Name. URL.
• In-text citation: (Smith 2018)
• Reference list: Smith, John. 2018. “The Importance of Recycling.” Environmental News Network. https://www.enn.com/articles/54374-the-importance-of-recycling.
• Footnote/Endnote citation: Author First Name Last Name, “Title of Webpage,” Website Name, URL (accessed Date).
• Bibliography citation: Author Last Name, First Name. “Title of Webpage.” Website Name. URL (accessed Date).
• Footnote/Endnote citation: John Smith, “The Importance of Recycling,” Environmental News Network, https://www.enn.com/articles/54374-the-importance-of-recycling (accessed April 8, 2023).
• Bibliography citation: Smith, John. “The Importance of Recycling.” Environmental News Network. https://www.enn.com/articles/54374-the-importance-of-recycling (accessed April 8, 2023).

NEWS ARTICLES:

• Reference list: Author Last Name, First Name. Year. “Title of Article.” Name of Newspaper, Month Day.
• In-text citation: (Johnson 2022)
• Reference list: Johnson, Mary. 2022. “New Study Finds Link Between Coffee and Longevity.” The New York Times, January 15.
• Footnote/Endnote citation: Author First Name Last Name, “Title of Article,” Name of Newspaper (City), Month Day, Year.
• Bibliography citation: Author Last Name, First Name. “Title of Article.” Name of Newspaper (City), Month Day, Year.
• Footnote/Endnote citation: Mary Johnson, “New Study Finds Link Between Coffee and Longevity,” The New York Times (New York), January 15, 2022.
• Bibliography citation: Johnson, Mary. “New Study Finds Link Between Coffee and Longevity.” The New York Times (New York), January 15, 2022.

Harvard referencing style

Format: Author’s Last name, First initial. (Year of publication). Title of book. Publisher.

Example: Smith, J. (2008). The Art of War. Random House.

Journal article:

Format: Author’s Last name, First initial. (Year of publication). Title of article. Title of journal, volume number(issue number), page range.

Example: Brown, M. (2012). The impact of social media on business communication. Harvard Business Review, 90(12), 85-92.

Research paper:

Format: Author’s Last name, First initial. (Year of publication). Title of paper. In Editor’s First initial. Last name (Ed.), Title of book (page range). Publisher.

Example: Johnson, R. (2015). The effects of climate change on agriculture. In S. Lee (Ed.), Climate Change and Sustainable Development (pp. 45-62). Springer.

Format: Author’s Last name, First initial. (Year, Month Day of publication). Title of page. Website name. URL.

Example: Smith, J. (2017, May 23). The history of the internet. Encyclopedia Britannica. https://www.britannica.com/topic/history-of-the-internet

News article:

Format: Author’s Last name, First initial. (Year, Month Day of publication). Title of article. Title of newspaper, page number (if applicable).

Example: Thompson, E. (2022, January 5). New study finds coffee may lower risk of dementia. The New York Times, A1.

IEEE Format

Author(s). (Year of Publication). Title of Book. Publisher.

Smith, J. K. (2015). The Power of Habit: Why We Do What We Do in Life and Business. Random House.

Journal Article:

Author(s). (Year of Publication). Title of Article. Title of Journal, Volume Number (Issue Number), page numbers.

Johnson, T. J., & Kaye, B. K. (2016). Interactivity and the Future of Journalism. Journalism Studies, 17(2), 228-246.

Author(s). (Year of Publication). Title of Paper. Paper presented at Conference Name, Location.

Jones, L. K., & Brown, M. A. (2018). The Role of Social Media in Political Campaigns. Paper presented at the 2018 International Conference on Social Media and Society, Copenhagen, Denmark.

• Website: Author(s) or Organization Name. (Year of Publication or Last Update). Title of Webpage. Website Name. URL.

Example: National Aeronautics and Space Administration. (2019, August 29). NASA’s Mission to Mars. NASA. https://www.nasa.gov/topics/journeytomars/index.html

• News Article: Author(s). (Year of Publication). Title of Article. Name of News Source. URL.

Example: Johnson, M. (2022, February 16). Climate Change: Is it Too Late to Save the Planet? CNN. https://www.cnn.com/2022/02/16/world/climate-change-planet-scn/index.html

Vancouver Style

In-text citation: Use superscript numbers to cite sources in the text, e.g., “The study conducted by Smith and Johnson^1 found that…”.

Reference list citation: Format: Author(s). Title of book. Edition if any. Place of publication: Publisher; Year of publication.

Example: Smith J, Johnson L. Introduction to Molecular Biology. 2nd ed. New York: Wiley-Blackwell; 2015.

In-text citation: Use superscript numbers to cite sources in the text, e.g., “Several studies have reported that^1,2,3…”.

Reference list citation: Format: Author(s). Title of article. Abbreviated name of journal. Year of publication; Volume number (Issue number): Page range.

Example: Jones S, Patel K, Smith J. The effects of exercise on cardiovascular health. J Cardiol. 2018; 25(2): 78-84.

In-text citation: Use superscript numbers to cite sources in the text, e.g., “Previous research has shown that^1,2,3…”.

Reference list citation: Format: Author(s). Title of paper. In: Editor(s). Title of the conference proceedings. Place of publication: Publisher; Year of publication. Page range.

Example: Johnson L, Smith J. The role of stem cells in tissue regeneration. In: Patel S, ed. Proceedings of the 5th International Conference on Regenerative Medicine. London: Academic Press; 2016. p. 68-73.

In-text citation: Use superscript numbers to cite sources in the text, e.g., “According to the World Health Organization^1…”.

Reference list citation: Format: Author(s). Title of webpage. Name of website. URL [Accessed Date].

Example: World Health Organization. Coronavirus disease (COVID-19) advice for the public. World Health Organization. https://www.who.int/emergencies/disease/novel-coronavirus-2019/advice-for-public [Accessed 3 March 2023].

In-text citation: Use superscript numbers to cite sources in the text, e.g., “According to the New York Times^1…”.

Reference list citation: Format: Author(s). Title of article. Name of newspaper. Year Month Day; Section (if any): Page number.

Example: Jones S. Study shows that sleep is essential for good health. The New York Times. 2022 Jan 12; Health: A8.

Author(s). Title of Book. Edition Number (if it is not the first edition). Publisher: Place of publication, Year of publication.

Example: Smith, J. Chemistry of Natural Products. 3rd ed.; CRC Press: Boca Raton, FL, 2015.

Journal articles:

Author(s). Article Title. Journal Name Year, Volume, Inclusive Pagination.

Example: Garcia, A. M.; Jones, B. A.; Smith, J. R. Selective Synthesis of Alkenes from Alkynes via Catalytic Hydrogenation. J. Am. Chem. Soc. 2019, 141, 10754-10759.

Research papers:

Author(s). Title of Paper. Journal Name Year, Volume, Inclusive Pagination.

Example: Brown, H. D.; Jackson, C. D.; Patel, S. D. A New Approach to Photovoltaic Solar Cells. J. Mater. Chem. 2018, 26, 134-142.

Author(s) (if available). Title of Webpage. Name of Website. URL (accessed Month Day, Year).

Example: National Institutes of Health. Heart Disease and Stroke. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/heart-disease-and-stroke (accessed April 7, 2023).

News articles:

Author(s). Title of Article. Name of News Publication. Date of Publication. URL (accessed Month Day, Year).

Example: Friedman, T. L. The World is Flat. New York Times. April 7, 2023. https://www.nytimes.com/2023/04/07/opinion/world-flat-globalization.html (accessed April 7, 2023).

In AMA Style Format, the citation for a book should include the following information, in this order:

• Title of book (in italics)
• Edition (if applicable)
• Place of publication
• Year of publication

Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th ed. New York, NY: W. H. Freeman; 2000.

In AMA Style Format, the citation for a journal article should include the following information, in this order:

• Title of article
• Abbreviated title of journal (in italics)
• Year of publication; volume number(issue number):page numbers.

Chen H, Huang Y, Li Y, et al. Effects of mindfulness-based stress reduction on depression in adolescents and young adults: a systematic review and meta-analysis. JAMA Netw Open. 2020;3(6):e207081. doi:10.1001/jamanetworkopen.2020.7081

In AMA Style Format, the citation for a research paper should include the following information, in this order:

• Title of paper
• Name of journal or conference proceeding (in italics)
• Volume number(issue number):page numbers.

Bredenoord AL, Kroes HY, Cuppen E, Parker M, van Delden JJ. Disclosure of individual genetic data to research participants: the debate reconsidered. Trends Genet. 2011;27(2):41-47. doi:10.1016/j.tig.2010.11.004

In AMA Style Format, the citation for a website should include the following information, in this order:

• Title of web page or article
• Name of website (in italics)
• Date of publication or last update (if available)
• URL (website address)
• Date of access (month day, year)

Centers for Disease Control and Prevention. How to protect yourself and others. CDC. Published February 11, 2022. Accessed February 14, 2022. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html

In AMA Style Format, the citation for a news article should include the following information, in this order:

• Name of newspaper or news website (in italics)
• Date of publication

Gorman J. Scientists use stem cells from frogs to build first living robots. The New York Times. January 13, 2020. Accessed January 14, 2020. https://www.nytimes.com/2020/01/13/science/living-robots-xenobots.html

Bluebook Format

One author: Daniel J. Solove, The Future of Reputation: Gossip, Rumor, and Privacy on the Internet (Yale University Press 2007).

Two or more authors: Martha Nussbaum and Saul Levmore, eds., The Offensive Internet: Speech, Privacy, and Reputation (Harvard University Press 2010).

Journal article

One author: Daniel J. Solove, “A Taxonomy of Privacy,” University of Pennsylvania Law Review 154, no. 3 (January 2006): 477-560.

Two or more authors: Ethan Katsh and Andrea Schneider, “The Emergence of Online Dispute Resolution,” Journal of Dispute Resolution 2003, no. 1 (2003): 7-19.

One author: Daniel J. Solove, “A Taxonomy of Privacy,” GWU Law School Public Law Research Paper No. 113, 2005.

Two or more authors: Ethan Katsh and Andrea Schneider, “The Emergence of Online Dispute Resolution,” Cyberlaw Research Paper Series Paper No. 00-5, 2000.

WebsiteElectronic Frontier Foundation, “Surveillance Self-Defense,” accessed April 8, 2023, https://ssd.eff.org/.

News article

One author: Mark Sherman, “Court Deals Major Blow to Net Neutrality Rules,” ABC News, January 14, 2014, https://abcnews.go.com/Politics/wireStory/court-deals-major-blow-net-neutrality-rules-21586820.

Two or more authors: Siobhan Hughes and Brent Kendall, “AT&T Wins Approval to Buy Time Warner,” Wall Street Journal, June 12, 2018, https://www.wsj.com/articles/at-t-wins-approval-to-buy-time-warner-1528847249.

In-Text Citation: (Author’s last name Year of Publication: Page Number)

Example: (Smith 2010: 35)

Reference List Citation: Author’s last name First Initial. Title of Book. Edition. Place of publication: Publisher; Year of publication.

Example: Smith J. Biology: A Textbook. 2nd ed. New York: Oxford University Press; 2010.

Example: (Johnson 2014: 27)

Reference List Citation: Author’s last name First Initial. Title of Article. Abbreviated Title of Journal. Year of publication;Volume(Issue):Page Numbers.

Example: Johnson S. The role of dopamine in addiction. J Neurosci. 2014;34(8): 2262-2272.

Example: (Brown 2018: 10)

Reference List Citation: Author’s last name First Initial. Title of Paper. Paper presented at: Name of Conference; Date of Conference; Place of Conference.

Example: Brown R. The impact of social media on mental health. Paper presented at: Annual Meeting of the American Psychological Association; August 2018; San Francisco, CA.

Example: (World Health Organization 2020: para. 2)

Reference List Citation: Author’s last name First Initial. Title of Webpage. Name of Website. URL. Published date. Accessed date.

Example: World Health Organization. Coronavirus disease (COVID-19) pandemic. WHO website. https://www.who.int/emergencies/disease-coronavirus-2019. Updated August 17, 2020. Accessed September 5, 2021.

Example: (Smith 2019: para. 5)

Reference List Citation: Author’s last name First Initial. Title of Article. Title of Newspaper or Magazine. Year of publication; Month Day:Page Numbers.

Example: Smith K. New study finds link between exercise and mental health. The New York Times. 2019;May 20: A6.

Purpose of Research Paper Citation

The purpose of citing sources in a research paper is to give credit to the original authors and acknowledge their contribution to your work. By citing sources, you are also demonstrating the validity and reliability of your research by showing that you have consulted credible and authoritative sources. Citations help readers to locate the original sources that you have referenced and to verify the accuracy and credibility of your research. Additionally, citing sources is important for avoiding plagiarism, which is the act of presenting someone else’s work as your own. Proper citation also shows that you have conducted a thorough literature review and have used the existing research to inform your own work. Overall, citing sources is an essential aspect of academic writing and is necessary for building credibility, demonstrating research skills, and avoiding plagiarism.

Advantages of Research Paper Citation

There are several advantages of research paper citation, including:

• Giving credit: By citing the works of other researchers in your field, you are acknowledging their contribution and giving credit where it is due.
• Strengthening your argument: Citing relevant and reliable sources in your research paper can strengthen your argument and increase its credibility. It shows that you have done your due diligence and considered various perspectives before drawing your conclusions.
• Demonstrating familiarity with the literature : By citing various sources, you are demonstrating your familiarity with the existing literature in your field. This is important as it shows that you are well-informed about the topic and have done a thorough review of the available research.
• Providing a roadmap for further research: By citing relevant sources, you are providing a roadmap for further research on the topic. This can be helpful for future researchers who are interested in exploring the same or related issues.
• Building your own reputation: By citing the works of established researchers in your field, you can build your own reputation as a knowledgeable and informed scholar. This can be particularly helpful if you are early in your career and looking to establish yourself as an expert in your field.

About the author

Muhammad Hassan

Researcher, Academic Writer, Web developer

You may also like

Research Paper Conclusion – Writing Guide and...

Appendices – Writing Guide, Types and Examples

Delimitations in Research – Types, Examples and...

Scope of the Research – Writing Guide and...

Research Contribution – Thesis Guide

Research Paper Title – Writing Guide and Example

How To Cite a Research Paper: MLA, APA, and Chicago Style

• Posted on January 25, 2022

When you’re writing a research paper, you’ll use a variety of sources to find information. You might find that you end up using other people’s research papers as sources of information for your own work. You need to know how to cite a research paper properly.

Using text citations tells readers where you got your information, and help build a sense of trust, allowing the reader to feel confident that you haven’t falsified the information. You have to prove that you’ve done the research and found data to back up the claims you’re making.

Writing a paper without giving credit to people whose work you’re using is plagiarism. Unless you’re citing a direct quote you want to change the language enough, by putting the quote in your own words, so it sounds like original content. Quetext’s plagiarism checker  helps you search for similar content across the web so you can turn in a completely original paper.

Whether you’re submitting a research paper to school or for publication in a peer-reviewed journal, you’re required to cite your sources. Editors often reread the work of writers and researchers to ensure the information is factual. A teacher or professor will definitely check that your sources are accurate, so using tools like Quetext will help avoid unintentional plagiarism errors or wrongfully cited information.

Why Text Citations are Important

If you don’t have sources to back up your research, others might accuse you of spreading false information or plagiarism. Any journal publishing papers should verify what they’re printing, but ultimately, as the author, the buck stops with you.

In general, it’s a kindness to cite your sources. The people who created them did a lot of work, so it’s wrong to claim ownership of their ideas and information. But it’s also an ethical issue that can have major repercussions.

There have been cases where researchers  make up information  or falsify their sources and must face the consequences. People depend on factual information and don’t react well when they realize you lied to them or falsely paraphrase information.

That’s why it’s common knowledge to write a well-researched paper with text citations. If anyone claims your information is incorrect, you can point them to the source where you found the data. This doesn’t guarantee that the information you cited is correct, but you’ll be able to provide readers with a source of where you gathered your information.

When you’re citing other people’s research papers, make sure the source is legitimate. You should only use peer-reviewed journals so you know the article has gone through edits and fact-checking. Something identified as a research paper that is only on a blog or message board isn’t always a reliable source.

Many students like to use  Wikipedia  because there’s so much information available from one source. However, Wikipedia allows users to edit the information. What you read in a specific entry might not be true. It’s best to scroll down to the works cited and go to the original source yourself. If you can’t find a reliable, original source for the information, you shouldn’t use it.

Using the Various Citation Styles

The information used in any citation is basically the same across each style guide. The formatting and order of some elements may vary, so it’s important to know the difference between Modern Language Association (MLA), American Psychological Association (APA), and Chicago Styles.

The style you use depends on what type of writing you’re doing. All will use these basic elements in some form or another:

Source name

Volume and edition

Publication date

Page numbers

Publisher name

City and country of the publisher

URL and DOI for web pages and digital sources

The date you accessed the material

In addition to a reference list at the end of your work, you’ll also use in-text citations. Whenever you reference an idea or data that isn’t yours, you cite it. Each style has different types of in-text citations as well. Read on to find out about each citation format.

You’ll likely use the  MLA citation guide  if you’re writing papers in the humanities, such as for language arts, literary criticism, cultural studies, and more. The current edition of the MLA Handbook is the ninth because the style constantly evolves. As new technology creates new potential sources, MLA adds information to help students and researchers cite everything correctly.

The MLA Handbook has instructions on how to cite song lyrics, social media posts, and digital images, along with all of the standard research outlets. The book also gives detailed information on how to cite a research paper.

The MLA Handbook includes information about how to format your reference page. Use a 12-pt standard font like Times New Roman, so the text in italics is clearly different from the regular font. Center the title, Works Cited, at the top of the page. Your last name and page number are in the top right corner, and the reference page always comes at the end of your document.

Alphabetize citations according to the last name of the author. Left-align the citations and double-space them with no extra lines between each entry. When a citation goes beyond a single line, use a hanging indent to format it correctly. This lets the reader know it’s still the same citation continuing on.

Now that you know the basic format for the Works Cited page read on to find out how to cite a research paper for inclusion on this list.

Citing a Research Paper in MLA Style

When you’re citing a research paper in MLA style, you start with the author’s full name, putting the last name of the author first, followed by the title of the research paper in quotation marks. Next comes the the title of the journal that published the paper in italics, followed by the volume number, issue number, and date of publication.

You’ll also include the page number since the paper is in a journal with many pages. If you found the source online, include the digital object identifier or DOI. The DOI is a way to give a document a permanent web address so people reading your work can easily find the source.

MLA format also asks you to include the date you accessed online materials. Doing so gives your reader more information about when you read the research if it changed since that date. Here is an example of a research paper citation in MLA style:

Writer, Maria. “My Research Paper.” Research Journal, vol 3, no. 4, 2020, pp. 7-9. doi:12.34/mfs.12.34. Accessed 13 March 2021.

If the work wasn’t published online, you could stop your citation after the page numbers.

Sometimes you might find research papers that aren’t published in a scholarly journal. You can still use those in your work, but the MLA citation will look different. You’ll still put the last name of the author first, but instead of putting the title of the research paper in quotation marks, you’ll put it in italics.

Here is an example of an unpublished research paper citation in MLA style:

Writer, Maria. My Research Paper. 2020, http://websiteused.com . Accessed 13 March 2021.

These two examples show you how to document the source on your Works Cited page. In-text citations look different.

In-Text Citations for a Research Paper in MLA Style

When you’re working with the MLA format, an in-text reference requires a parenthetical citation.

If you refer to someone else’s research in a sentence, either with a direct quote or by paraphrasing, you need to give that author credit. At the end of the sentence where you use the information, you’ll put the author’s information in parenthesis and then put the sentence’s ending punctuation.

You use the author’s last name and the page number where you found the information for in-text citations. Then anyone reading your work can go to your Works Cited page, find the entry by the author’s last name, and access the document themselves. The page number directs them to where you got the specific information, so they don’t have to read the whole paper to find it. Here is an example of an in-text citation in MLA style:

Over 80% of the city’s garbage ended up in the ocean (Writer, 8).

You might mention the author’s name in your sentence. In that case, the parenthetical citation only needs to have the page numbers for reference. Here is an example:

According to Maria Writer, over 80% of the city’s garbage went into the ocean (8).

Researchers in the social science field, like sociology, anthropology, and psychology, use the  APA style  in their work. Like the MLA Handbook, the Publication Manual of the American Psychological Association has gone through changes over the years. It’s currently on the 7th edition.

In addition to helping you understand how to cite research, the Publication Manual of the American Psychological Association has information about how to format your paper to include tables, figures, and headings that often accompany scientific journal articles.

The Publication Manual of the American Psychological Association also tells you how to format your reference page. In MLA style, this is the Works Cited page. For APA style, it’s either the Reference List or Reference Page.

This page uses the same font style as the rest of the paper but starts on its own page with a number in the top right corner. The title of the page is bold and centered at the top and should simply read “References.”

List citations in alphabetical order by author’s last name regardless of the type of source. Each citation is double-spaced and has a hanging indent if it goes beyond one line.

Now that you understand how to properly format your APA reference page, learn how to cite a research paper to include on the list.

Citing a Research Paper in APA Style

When you use a research paper in your work, you need to include it on your APA references page at the end of your document.

An APA citation includes the same information as the MLA format but in a different order. The citation starts with the author’s last name but only uses their first initial. Then comes the year of publication in parenthesis.

The paper’s title follows, then the title of the journal in italics. You also include the journal volume, issue number, and page numbers. As with MLA citations, include a DOI if you found the research paper online. Here is an example of a published research paper cited in APA format:

Writer, M. (2020). My Research Paper. Research Journal, 3(4), 7-9. doi:12.34/mfs.12.34

If the paper isn’t published in a journal, you can still use it in your work with a proper citation. Here is an example:

Writer, M. (2020). My Research Paper [PDF]. Retrieved from http://websiteused.com

In-Text Citations for a Research Paper in APA Style

In-text citations in the APA format differ from MLA style. You still put it in parenthesis, but you include different information. For APA parentheticals, include the author’s last name and the paper’s year of publication. This method applies when you’re summarizing or paraphrasing the author’s idea. Here is an example of an in-text citation for a research paper in APA style:

Over 80% of the city’s garbage went into the ocean (Writer, 2020).

If you’re using a direct quote from the work you need to include the page number so the reader can find the quotation. Here is an example:

Maria Writer said, “Over 80% of the city’s garbage is going into the ocean” (2020, p. 8).

Chicago Style

Chicago Style  got its name from the University of Chicago, where the style originated. Writers use this format for works in the field of history, but you can also use it for the sciences, social sciences, and humanities.

MLA style has a Works Cited page, APA has References, and Chicago Style differs because it includes a Bibliography. The page comes at the end of your work with a page number in the top right corner. The title, “Bibliography,” is bold and centered at the top.

You will single-space your citations, but you’ll add an extra line between each entry. As with the other reference pages, you’ll left-align the work and use a hanging indent when a citation continues onto a second line.

Having an overview of how to format the bibliography will help you understand the citation styles for a research paper.

Citing a Research Paper in Chicago Style

Citations in Chicago Style are a mix of MLA and APA formats. It’s easiest to follow this template:

Writer, Maria. 2020. “My Research Paper.” Research Journal 3 (4): 7-9. doi:12.34/mfs.12.34.

As with other styles, you can reference an unpublished research paper as a document. Here is an example:

Writer, Maria. 2020. My Research Paper. PDF. http://websiteused.com .

In both instances, if there are multiple authors for a paper, list the rest of the authors in normal format. For example:

Author, Alan, Stanley Sample, and Maria Writer. 2020. “My Research Paper.” Research Journal 3 (4): 7-9. doi:12.34/mfs.12.34.

In-Text Citations for a Research Paper in Chicago Style

An in-text citation in Chicago Style is much simpler than both MLA and APA formats. You only need to include the last name of the author and year of publication in parenthesis with no comma in between them. For example:

Almost 80% of the city’s garbage goes into the ocean (Writer 2020).

You’ll include the page number for specificity if you’re quoting the author. Here’s an example:

Maria Writer said, “Over 80% of the city’s garbage is going into the ocean” (2020, 8).

You can also use endnotes in Chicago Style. A citation refers the reader to your source, but an endnote includes a bit of an explanation of why you used it. The information included in an endnote would disrupt the flow of your paper, but it’s still something you want the reader to know.

Make Text Citations Easy

Knowing when you need to cite a source helps you manage your research. Anytime you find information that you’re going to paraphrase, summarize, or quote in your work, you need to cite the source. The full citation will go on your reference page, but you’ll need an in-text citation where you use the information in your paper.

When you’re stating something that is  common knowledge , there’s no need to make a citation. Common knowledge is something that your reader would believe without needing proof. You can check if something is common knowledge by searching for it and finding it mentioned, without a citation, in at least five sources.

Once you learn the basics about citing a research paper in MLA, APA, and Chicago Styles, you’ll feel more confident in your work. The important thing is to pay attention to small details, like capitalization, italics and the use of abbreviations. But there’s no need to do it all on your own—Quetext has a  citation assistant  waiting to help. Give Quetext citation generator a try on your next project.

Sign Up for Quetext Today!

Click below to find a pricing plan that fits your needs.

You May Also Like

Empowering Educators: How AI Detection Enhances Teachers’ Workload

• Posted on March 14, 2024

The Ethical Dimension | Navigating the Challenges of AI Detection in Education

• Posted on March 8, 2024

How to Write a Thesis Statement & Essay Outline

• Posted on February 29, 2024 February 29, 2024

The Crucial Role of Grammar and Spell Check in Student Assignments

• Posted on February 23, 2024 February 23, 2024

Revolutionizing Education: The Role of AI Detection in Academic Integrity

• Posted on February 15, 2024

How Reliable are AI Content Detectors? Which is Most Reliable?

• Posted on February 8, 2024 February 8, 2024

What Is an Article Spinner?

• Posted on February 2, 2024 February 2, 2024

Recognizing & Avoiding Plagiarism in Your Research Paper

• Posted on January 26, 2024 January 26, 2024

Input your search keywords and press Enter.

University Library

Start your research.

• Research Process
• Find Background Info
• Find Sources through the Library
• Evaluate Your Info
• Cite Your Sources
• Evaluate, Write & Cite

• is the right thing to do  to give credit to those who had the idea
• shows that you have read and understand  what experts have had to say about your topic
• helps people find the sources  that you used in case they want to read more about the topic
• provides   evidence  for your arguments
• is professional and  standard practice   for students and scholars

What is a Citation?

A citation identifies for the reader the original source for an idea, information, or image that is referred to in a work.

• In the body of a paper, the  in-text citation  acknowledges the source of information used.
• At the end of a paper, the citations are compiled on a  References  or  Works Cited  list. A basic citation includes the author, title, and publication information of the source. 

From:  Lemieux  Library,  University  of Seattle 

Why Should You Cite?

Quoting Are you quoting two or more consecutive words from a source? Then the original source should be cited and the words or phrase placed in quotes. 

Paraphrasing If an idea or information comes from another source,  even if you put it in your own words , you still need to credit the source.  General vs. Unfamiliar Knowledge You do not need to cite material which is accepted common knowledge. If in doubt whether your information is common knowledge or not, cite it. Formats We usually think of books and articles. However, if you use material from web sites, films, music, graphs, tables, etc. you'll also need to cite these as well.

Plagiarism is presenting the words or ideas of someone else as your own without proper acknowledgment of the source. When you work on a research paper and use supporting material from works by others, it's okay to quote people and use their ideas, but you do need to correctly credit them. Even when you summarize or paraphrase information found in books, articles, or Web pages, you must acknowledge the original author.

Citation Style Help

Helpful links:

• MLA ,  Works Cited : A Quick Guide (a template of core elements)
• CSE  (Council of Science Editors)

For additional writing resources specific to styles listed here visit the  Purdue OWL Writing Lab

Citation and Bibliography Resources

• How to Write an Annotated Bibliography
• Zotero Basics
• << Previous: Evaluate Your Info
• Next: Evaluate, Write & Cite >>

Creative Commons Attribution 3.0 License except where otherwise noted.

Land Acknowledgement

The land on which we gather is the unceded territory of the Awaswas-speaking Uypi Tribe. The Amah Mutsun Tribal Band, comprised of the descendants of indigenous people taken to missions Santa Cruz and San Juan Bautista during Spanish colonization of the Central Coast, is today working hard to restore traditional stewardship practices on these lands and heal from historical trauma.

The land acknowledgement used at UC Santa Cruz was developed in partnership with the Amah Mutsun Tribal Band Chairman and the Amah Mutsun Relearning Program at the UCSC Arboretum .

Home / Guides / Citation Guides / How to Cite Sources

How to Cite Sources

Here is a complete list for how to cite sources. Most of these guides present citation guidance and examples in MLA, APA, and Chicago.

If you’re looking for general information on MLA or APA citations , the EasyBib Writing Center was designed for you! It has articles on what’s needed in an MLA in-text citation , how to format an APA paper, what an MLA annotated bibliography is, making an MLA works cited page, and much more!

MLA Format Citation Examples

The Modern Language Association created the MLA Style, currently in its 9th edition, to provide researchers with guidelines for writing and documenting scholarly borrowings.  Most often used in the humanities, MLA style (or MLA format ) has been adopted and used by numerous other disciplines, in multiple parts of the world.

MLA provides standard rules to follow so that most research papers are formatted in a similar manner. This makes it easier for readers to comprehend the information. The MLA in-text citation guidelines, MLA works cited standards, and MLA annotated bibliography instructions provide scholars with the information they need to properly cite sources in their research papers, articles, and assignments.

• Book Chapter
• Conference Paper
• Documentary
• Encyclopedia
• Google Images
• Kindle Book
• Memorial Inscription
• Museum Exhibit
• Painting or Artwork
• PowerPoint Presentation
• Sheet Music
• Thesis or Dissertation
• YouTube Video

APA Format Citation Examples

The American Psychological Association created the APA citation style in 1929 as a way to help psychologists, anthropologists, and even business managers establish one common way to cite sources and present content.

APA is used when citing sources for academic articles such as journals, and is intended to help readers better comprehend content, and to avoid language bias wherever possible. The APA style (or APA format ) is now in its 7th edition, and provides citation style guides for virtually any type of resource.

Chicago Style Citation Examples

The Chicago/Turabian style of citing sources is generally used when citing sources for humanities papers, and is best known for its requirement that writers place bibliographic citations at the bottom of a page (in Chicago-format footnotes ) or at the end of a paper (endnotes).

The Turabian and Chicago citation styles are almost identical, but the Turabian style is geared towards student published papers such as theses and dissertations, while the Chicago style provides guidelines for all types of publications. This is why you’ll commonly see Chicago style and Turabian style presented together. The Chicago Manual of Style is currently in its 17th edition, and Turabian’s A Manual for Writers of Research Papers, Theses, and Dissertations is in its 8th edition.

Citing Specific Sources or Events

• Declaration of Independence
• Gettysburg Address
• Martin Luther King Jr. Speech
• President Obama’s Farewell Address
• President Trump’s Inauguration Speech
• White House Press Briefing

Additional FAQs

• Citing Archived Contributors
• Citing a Blog
• Citing a Book Chapter
• Citing a Source in a Foreign Language
• Citing an Image
• Citing a Song
• Citing Special Contributors
• Citing a Translated Article
• Citing a Tweet

6 Interesting Citation Facts

The world of citations may seem cut and dry, but there’s more to them than just specific capitalization rules, MLA in-text citations , and other formatting specifications. Citations have been helping researches document their sources for hundreds of years, and are a great way to learn more about a particular subject area.

Ever wonder what sets all the different styles apart, or how they came to be in the first place? Read on for some interesting facts about citations!

1. There are Over 7,000 Different Citation Styles

You may be familiar with MLA and APA citation styles, but there are actually thousands of citation styles used for all different academic disciplines all across the world. Deciding which one to use can be difficult, so be sure to ask you instructor which one you should be using for your next paper.

2. Some Citation Styles are Named After People

While a majority of citation styles are named for the specific organizations that publish them (i.e. APA is published by the American Psychological Association, and MLA format is named for the Modern Language Association), some are actually named after individuals. The most well-known example of this is perhaps Turabian style, named for Kate L. Turabian, an American educator and writer. She developed this style as a condensed version of the Chicago Manual of Style in order to present a more concise set of rules to students.

3. There are Some Really Specific and Uniquely Named Citation Styles

How specific can citation styles get? The answer is very. For example, the “Flavour and Fragrance Journal” style is based on a bimonthly, peer-reviewed scientific journal published since 1985 by John Wiley & Sons. It publishes original research articles, reviews and special reports on all aspects of flavor and fragrance. Another example is “Nordic Pulp and Paper Research,” a style used by an international scientific magazine covering science and technology for the areas of wood or bio-mass constituents.

4. More citations were created on  EasyBib.com  in the first quarter of 2018 than there are people in California.

The US Census Bureau estimates that approximately 39.5 million people live in the state of California. Meanwhile, about 43 million citations were made on EasyBib from January to March of 2018. That’s a lot of citations.

5. “Citations” is a Word With a Long History

The word “citations” can be traced back literally thousands of years to the Latin word “citare” meaning “to summon, urge, call; put in sudden motion, call forward; rouse, excite.” The word then took on its more modern meaning and relevance to writing papers in the 1600s, where it became known as the “act of citing or quoting a passage from a book, etc.”

6. Citation Styles are Always Changing

The concept of citations always stays the same. It is a means of preventing plagiarism and demonstrating where you relied on outside sources. The specific style rules, however, can and do change regularly. For example, in 2018 alone, 46 new citation styles were introduced , and 106 updates were made to exiting styles. At EasyBib, we are always on the lookout for ways to improve our styles and opportunities to add new ones to our list.

Why Citations Matter

Here are the ways accurate citations can help your students achieve academic success, and how you can answer the dreaded question, “why should I cite my sources?”

They Give Credit to the Right People

Citing their sources makes sure that the reader can differentiate the student’s original thoughts from those of other researchers. Not only does this make sure that the sources they use receive proper credit for their work, it ensures that the student receives deserved recognition for their unique contributions to the topic. Whether the student is citing in MLA format , APA format , or any other style, citations serve as a natural way to place a student’s work in the broader context of the subject area, and serve as an easy way to gauge their commitment to the project.

They Provide Hard Evidence of Ideas

Having many citations from a wide variety of sources related to their idea means that the student is working on a well-researched and respected subject. Citing sources that back up their claim creates room for fact-checking and further research . And, if they can cite a few sources that have the converse opinion or idea, and then demonstrate to the reader why they believe that that viewpoint is wrong by again citing credible sources, the student is well on their way to winning over the reader and cementing their point of view.

They Promote Originality and Prevent Plagiarism

The point of research projects is not to regurgitate information that can already be found elsewhere. We have Google for that! What the student’s project should aim to do is promote an original idea or a spin on an existing idea, and use reliable sources to promote that idea. Copying or directly referencing a source without proper citation can lead to not only a poor grade, but accusations of academic dishonesty. By citing their sources regularly and accurately, students can easily avoid the trap of plagiarism , and promote further research on their topic.

They Create Better Researchers

By researching sources to back up and promote their ideas, students are becoming better researchers without even knowing it! Each time a new source is read or researched, the student is becoming more engaged with the project and is developing a deeper understanding of the subject area. Proper citations demonstrate a breadth of the student’s reading and dedication to the project itself. By creating citations, students are compelled to make connections between their sources and discern research patterns. Each time they complete this process, they are helping themselves become better researchers and writers overall.

When is the Right Time to Start Making Citations?

Make in-text/parenthetical citations as you need them.

As you are writing your paper, be sure to include references within the text that correspond with references in a works cited or bibliography. These are usually called in-text citations or parenthetical citations in MLA and APA formats. The most effective time to complete these is directly after you have made your reference to another source. For instance, after writing the line from Charles Dickens’ A Tale of Two Cities : “It was the best of times, it was the worst of times…,” you would include a citation like this (depending on your chosen citation style):

(Dickens 11).

This signals to the reader that you have referenced an outside source. What’s great about this system is that the in-text citations serve as a natural list for all of the citations you have made in your paper, which will make completing the works cited page a whole lot easier. After you are done writing, all that will be left for you to do is scan your paper for these references, and then build a works cited page that includes a citation for each one.

Need help creating an MLA works cited page ? Try the MLA format generator on EasyBib.com! We also have a guide on how to format an APA reference page .

2. Understand the General Formatting Rules of Your Citation Style Before You Start Writing

While reading up on paper formatting may not sound exciting, being aware of how your paper should look early on in the paper writing process is super important. Citation styles can dictate more than just the appearance of the citations themselves, but rather can impact the layout of your paper as a whole, with specific guidelines concerning margin width, title treatment, and even font size and spacing. Knowing how to organize your paper before you start writing will ensure that you do not receive a low grade for something as trivial as forgetting a hanging indent.

Don’t know where to start? Here’s a formatting guide on APA format .

3. Double-check All of Your Outside Sources for Relevance and Trustworthiness First

Collecting outside sources that support your research and specific topic is a critical step in writing an effective paper. But before you run to the library and grab the first 20 books you can lay your hands on, keep in mind that selecting a source to include in your paper should not be taken lightly. Before you proceed with using it to backup your ideas, run a quick Internet search for it and see if other scholars in your field have written about it as well. Check to see if there are book reviews about it or peer accolades. If you spot something that seems off to you, you may want to consider leaving it out of your work. Doing this before your start making citations can save you a ton of time in the long run.

Finished with your paper? It may be time to run it through a grammar and plagiarism checker , like the one offered by EasyBib Plus. If you’re just looking to brush up on the basics, our grammar guides  are ready anytime you are.

How useful was this post?

Click on a star to rate it!

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?

Citation Basics

Harvard Referencing

Plagiarism Basics

Plagiarism Checker

Upload a paper to check for plagiarism against billions of sources and get advanced writing suggestions for clarity and style.

Get Started

Research Skills Tutorial

• Turning A Topic Into A Research Question
• Getting Background Information About Your Topic
• Portfolio Activity 1
• Types of Information Sources
• Scholarly, Popular and Trade Information Sources
• Primary, Secondary and Tertiary Information Sources
• Current and Retrospective Information Sources
• Information Sources for Different Audiences and Purposes
• Portfolio Activity 2
• Library Databases vs. the Web
• Creating a Concept Chart
• Boolean Operators
• Refining Results by Date, Peer Review and Document Type
• Advanced Searching
• Advanced Searching with Descriptors
• Descriptor Chaining
• Citation Chaining (or Reference Mining)
• Searching Outside the SUNY Empire Library
• Searching Google
• Portfolio Activity 3
• Understanding Search Results
• Saving Search Results
• Portfolio Activity 4
• Credible Sources
• What Does the Information Source Tell You About Itself?
• Reliability
• Some More About Validity
• Portfolio Activity 5
• What Is Citing?
• What Is a Citation?
• Citation Styles
• Citing Tools and Tips
• Practice Activity 6
• Practice Activity 7 - Final Project

What Is A Citation?

When to cite.

A citation is a reference to the source of information used in your research. Any time you directly quote, paraphrase or summarize the essential elements of someone else's idea in your work, an in-text citation should follow. An in-text citation is a brief notation within the text of your paper or presentation which refers the reader to a fuller notation, or end-of-paper citation , that provides all necessary details about that source of information. Direct quotations should be surrounded by quotations marks and are generally used when the idea you want to capture is best expressed by the source.  Paraphrasing and summarizing involve rewording an essential idea from someone else's work, usually to either condense the point or to make it better fit your writing style. You do not have to cite your own ideas, unless they have been published. And you do not have to cite  common knowledge , or information that most people in your audience would know without having to look it up.

In-Text Citations

In-text citations alert the reader to an idea from an outside source.  

Parenthetical Notes

In MLA and APA styles, in-text citations usually appear as parenthetical notes (sometimes called parenthetical documentation ). They are called parenthetical notes because brief information about the source, usually the author's name, year of publication, and page number, is enclosed in parentheses as follows:  

MLA style: (Smith 263)

APA style: (Smith, 2013, p. 263)  

Parenthetical notes are inserted into the text of the paper at the end of a sentence or paragraph:>

In MLA and APA styles, in-text citations are associated with end-of-paper citations that provide full details about an information source. Note: Different source types and situations require different information within the parentheses. Refer to a style guide for the style you are using for details.

Note Numbers

In Chicago and CSE styles, in-text citations usually appear as superscript numerals, or note numbers , as follows:

These note numbers are associated with full citations that can appear as footnotes (bottom of page), endnotes (end of chapter or paper), or lists of cited references at the end of the paper.  

End-of-Paper Citations

End-of-paper citations, as well as footnotes and endnotes, include  full details about a source of information.  Citations contain different pieces of identifying information about your source depending on what type of source it is. In academic research, your sources will most commonly be articles from scholarly journals, and the citation for an article typically includes:  

• article title
• publication information (journal title, date, volume, issue, pages, etc.)
• DOI (digital object identifier).
• URL of the information source itself
• URL of the journal that published the article

There are many other types of sources you might use, including books, book chapters, films, song lyrics, musical scores, interviews, e-mails, blog entries, art works, lectures, websites and more. To determine which details are required for a citation for a particular source type, find that source type within the style guide for the citation style you are using. At the end of your research paper, full citations should be listed in order according to the citation style you are using:

• In MLA style, this list is called a W orks Cited page.  
• In APA style, it is called a References page.
• In CSE style, it is called a C ited References page.
• And, in Chicago style, there may be both a Notes page and a Bibliography page. 

Citations  In Library Databases

When you search the library's databases for articles or e-books, the list of search results you see is actually a list of full citations. Instead of being formatted according to MLA, APA, CSE, or Chicago style, these citations are formatted according to the database vendor's style. It is up to you to take the source information you find in a library database (or elsewhere) and format it according to the citation style you are using.

Accessibility Note

Please note: If you need to request accommodations with content linked to on this guide, on the basis of a disability, please contact Accessibility Resources and Services by emailing them .  Requests for accommodations should be submitted as early as possible to allow for sufficient planning. If you have questions, please visit the Accessibility Resources and Services website .

• << Previous: Why Cite?
• Next: Citation Styles >>
• Last Updated: Feb 21, 2024 1:37 PM
• URL: https://subjectguides.sunyempire.edu/researchskillstutorial

SpringShare Privacy Policy

• Safety & Security
• ITS Service Desk
• Facilities & Maintenance
• University Policies
• Web Accessibility
• Freedom of Information

© 2023 SUNY Empire State University The Torch logo is a trademark of SUNY Empire State University.

• USC Libraries
• Research Guides

Organizing Your Social Sciences Research Paper

• 11. Citing Sources
• Purpose of Guide
• Design Flaws to Avoid
• Independent and Dependent Variables
• Glossary of Research Terms
• Reading Research Effectively
• Narrowing a Topic Idea
• Broadening a Topic Idea
• Extending the Timeliness of a Topic Idea
• Academic Writing Style
• Choosing a Title
• Making an Outline
• Paragraph Development
• Research Process Video Series
• Executive Summary
• The C.A.R.S. Model
• Background Information
• The Research Problem/Question
• Theoretical Framework
• Citation Tracking
• Content Alert Services
• Evaluating Sources
• Primary Sources
• Secondary Sources
• Tiertiary Sources
• Scholarly vs. Popular Publications
• Qualitative Methods
• Quantitative Methods
• Insiderness
• Using Non-Textual Elements
• Limitations of the Study
• Common Grammar Mistakes
• Writing Concisely
• Avoiding Plagiarism
• Footnotes or Endnotes?
• Further Readings
• Generative AI and Writing
• USC Libraries Tutorials and Other Guides
• Bibliography

A citation is a formal reference to a published or unpublished source that you consulted and obtained information from while writing your research paper. It refers to a source of information that supports a factual statement, proposition, argument, or assertion or any quoted text obtained from a book, article, web site, or any other type of material . In-text citations are embedded within the body of your paper and use a shorthand notation style that refers to a complete description of the item at the end of the paper. Materials cited at the end of a paper may be listed under the heading References, Sources, Works Cited, or Bibliography. Rules on how to properly cite a source depends on the writing style manual your professor wants you to use for the class [e.g., APA, MLA, Chicago, Turabian, etc.]. Note that some disciplines have their own citation rules [e.g., law].

Citations: Overview. OASIS Writing Center, Walden University; Research and Citation. The Writing Lab and The OWL. Purdue University; Citing Sources. University Writing Center, Texas A&M University.

Reasons for Citing Your Sources

Reasons for Citing Sources in Your Research Paper

English scientist, Sir Isaac Newton, once wrote, "If I have seen further, it is by standing on the shoulders of giants.”* Citations support learning how to "see further" through processes of intellectual discovery, critical thinking, and applying a deliberate method of navigating through the scholarly landscape by tracking how cited works are propagated by scholars over time and the subsequent ways this leads to the devarication of new knowledge.

Listed below are specific reasons why citing sources is an important part of doing good research.

• Shows the reader where to find more information . Citations help readers expand their understanding and knowledge about the issues being investigated. One of the most effective strategies for locating authoritative, relevant sources about a research problem is to review materials cited in studies published by other authors. In this way, the sources you cite help the reader identify where to go to examine the topic in more depth and detail.
• Increases your credibility as an author . Citations to the words, ideas, and arguments of scholars demonstrates that you have conducted a thorough review of the literature and, therefore, you are reporting your research results or proposing recommended courses of action from an informed and critically engaged perspective. Your citations offer evidence that you effectively contemplated, evaluated, and synthesized sources of information in relation to your conceptualization of the research problem.
• Illustrates the non-linear and contested nature of knowledge creation . The sources you cite show the reader how you characterized the dynamics of prior knowledge creation relevant to the research problem and how you managed to effectively identify the contested relationships between problems and solutions proposed among scholars. Citations don't just list materials used in your study, they tell a story about how prior knowledge-making emerged from a constant state of creation, renewal, and transformation.
• Reinforces your arguments . Sources cited in your paper provide the evidence that readers need to determine that you properly addressed the “So What?” question. This refers to whether you considered the relevance and significance of the research problem, its implications applied to creating new knowledge, and its importance for improving practice. In this way, citations draw attention to and support the legitimacy and originality of your own ideas.
• Demonstrates that you "listened" to relevant conversations among scholars before joining in . Your citations tell the reader where you developed an understanding of the debates among scholars. They show how you educated yourself about ongoing conversations taking place within relevant communities of researchers before inserting your own ideas and arguments. In peer-reviewed scholarship, most of these conversations emerge within books, research reports, journal articles, and other cited works.
• Delineates alternative approaches to explaining the research problem . If you disagree with prior research assumptions or you believe that a topic has been understudied or you find that there is a gap in how scholars have understood a problem, your citations serve as the source materials from which to analyze and present an alternative viewpoint or to assert that a different course of action should be pursued. In short, the materials you cite serve as the means by which to argue persuasively against long-standing assumptions propagated in prior studies.
• Helps the reader understand contextual aspects of your research . Cited sources help readers understand the specific circumstances, conditions, and settings of the problem being investigated and, by extension, how your arguments can be fully understood and assessed. Citations place your line of reasoning within a specific contextualized framework based on how others have studied the problem and how you interpreted their findings in support of your overall research objectives.
• Frames the development of concepts and ideas within the literature . No topic in the social and behavioral sciences rests in isolation from research that has taken place in the past. Your citations help the reader understand the growth and transformation of the theoretical assumptions, key concepts, and systematic inquiries that emerged prior to your engagement with the research problem.
• Underscores what sources were most important to you . Your citations represent a set of choices made about what you determined to be the most important sources for understanding the topic. They not only list what you discovered, but why it matters and how the materials you chose to cite fit within the broader context of your research design and arguments. As part of an overall assessment of the study’s validity and reliability , the choices you make also helps the reader determine what research may have been excluded.
• Provides evidence of interdisciplinary thinking . An important principle of good research is to extend your review of the literature beyond the predominant disciplinary space where scholars have examined a topic. Citations provide evidence that you have integrated epistemological arguments, observations, and/or the methodological strategies from other disciplines into your paper, thereby demonstrating that you understand the complex, interconnected nature of contemporary research problems.
• Supports critical thinking and independent learning . Evaluating the authenticity, reliability, validity, and originality of prior research is an act of interpretation and introspective reasoning applied to assessing whether a source of information will contribute to understanding the problem in ways that are persuasive and align with your overall research objectives. Reviewing and citing prior studies represents a deliberate act of critically scrutinizing each source as part of your overall assessment of how scholars have confronted the research problem.
• Honors the achievements of others . As Susan Blum recently noted,** citations not only identify sources used, they acknowledge the achievements of scholars within the larger network of research about the topic. Citing sources is a normative act of professionalism within academe and a way to highlight and recognize the work of scholars who likely do not obtain any tangible benefits or monetary value from their research endeavors.

*Vernon. Jamie L. "On the Shoulder of Giants." American Scientist 105 (July-August 2017): 194.

**Blum, Susan D. "In Defense of the Morality of Citation.” Inside Higher Ed , January 29, 2024.

Aksnes, Dag W., Liv Langfeldt, and Paul Wouters. "Citations, Citation Indicators, and Research Quality: An Overview of Basic Concepts and Theories." Sage Open 9 (January-March 2019): https://doi.org/10.1177/2158244019829575; Blum, Susan Debra. My Word!: Plagiarism and College Culture . Ithaca, NY: Cornell University Press, 2009; Bretag, Tracey., editor. Handbook of Academic Integrity . Singapore: Springer Singapore, 2020; Ballenger, Bruce P. The Curious Researcher: A Guide to Writing Research Papers . 7th edition. Boston, MA: Pearson, 2012; D'Angelo, Barbara J. "Using Source Analysis to Promote Critical Thinking." Research Strategies 18 (Winter 2001): 303-309; Mauer, Barry and John Venecek. “Scholarship as Conversation.” Strategies for Conducting Literary Research, University of Central Florida, 2021; Why Cite? Poorvu Center for Teaching and Learning, Yale University; Citing Information. The Writing Center. University of North Carolina; Harvard Guide to Using Sources. Harvard College Writing Program. Harvard University; Newton, Philip. "Academic Integrity: A Quantitative Study of Confidence and Understanding in Students at the Start of Their Higher Education."  Assessment and Evaluation in Higher Education 41 (2016): 482-497; Referencing More Effectively. Academic Skills Centre. University of Canberra; Using Sources. Yale College Writing Center. Yale University; Vosburgh, Richard M. "Closing the Academic-practitioner Gap: Research Must Answer the “SO WHAT” Question." H uman Resource Management Review 32 (March 2022): 100633; When and Why to Cite Sources. Information Literacy Playlists, SUNY, Albany Libraries.

Structure and Writing Style

Referencing your sources means systematically showing what information or ideas you acquired from another author’s work, and identifying where that information come from . You must cite research in order to do research, but at the same time, you must delineate what are your original thoughts and ideas and what are the thoughts and ideas of others. Citations help achieve this. Procedures used to cite sources vary among different fields of study. If not outlined in your course syllabus or writing assignment, always speak with your professor about what writing style for citing sources should be used for the class because it is important to fully understand the citation style to be used in your paper, and to apply it consistently. If your professor defers and tells you to "choose whatever you want, just be consistent," then choose the citation style you are most familiar with or that is appropriate to your major [e.g., use Chicago style if its a history class; use APA if its an education course; use MLA if it is literature or a general writing course].

GENERAL GUIDELINES

1. Are there any reasons I should avoid referencing other people's work? No. If placed in the proper context, r eferencing other people's research is never an indication that your work is substandard or lacks originality. In fact, the opposite is true. If you write your paper without adequate references to previous studies, you are signaling to the reader that you are not familiar with the literature on the topic, thereby, undermining the validity of your study and your credibility as a researcher. Including references in academic writing is one of the most important ways to demonstrate your knowledge and understanding of how the research problem has been addressed. It is the intellectual packaging around which you present your thoughts and ideas to the reader.

2. What should I do if I find out that my great idea has already been studied by another researcher? It can be frustrating to come up with what you believe is a great topic only to find that it's already been thoroughly studied. However, do not become frustrated by this. You can acknowledge the prior research by writing in the text of your paper [see also Smith, 2002], then citing the complete source in your list of references. Use the discovery of prior studies as an opportunity to demonstrate the significance of the problem being investigated and, if applicable, as a means of delineating your analysis from those of others [e.g., the prior study is ten years old and doesn't take into account new variables]. Strategies for responding to prior research can include: stating how your study updates previous understandings about the topic, offering a new or different perspective, applying a different or innovative method of data gathering, and/or describing a new set of insights, guidelines, recommendations, best practices, or working solutions.

3. What should I do if I want to use an adapted version of someone else's work? You still must cite the original work. For example, maybe you are using a table of statistics from a journal article published in 1996 by author Smith, but you have altered or added new data to it. Reference the revised chart, such as, [adapted from Smith, 1996], then cite the complete source in your list of references. You can also use other terms in order to specify the exact relationship between the original source and the version you have presented, such as, "based on data from Smith [1996]...," or "summarized from Smith [1996]...." Citing the original source helps the reader locate where the information was first presented and under what context it was used as well as to evaluate how effectively you applied it to your own research.

4. What should I do if several authors have published very similar information or ideas? You can indicate that the idea or information can be found in the works of others by stating something similar to the following example: "Though many scholars have applied rational choice theory to understanding economic relations among nations [Smith, 1989; Jones, 1991; Johnson, 1994; Anderson, 2003], little attention has been given to applying the theory to examining the influence of non-governmental organizations in a globalized economy." If you only reference one author or only the most recent study, then your readers may assume that only one author has published on this topic, or more likely, they will conclude that you have not conducted a thorough literature review. Referencing all relevant authors of prior studies gives your readers a clear idea of the breadth of analysis you conducted in preparing to study the research problem. If there has been a significant number of prior studies on the topic, describe the most comprehensive and recent works because they will presumably discuss and reference the older studies. However, note in your review of the literature that there has been significant scholarship devoted to the topic so the reader knows that you are aware of the numerous prior studies.

5. What if I find exactly what I want to say in the writing of another researcher? In the social sciences, the rationale in duplicating prior research is generally governed by the passage of time, changing circumstances or conditions, or the emergence of variables that necessitate a new investigation . If someone else has recently conducted a thorough investigation of precisely the same research problem that you intend to study, then you likely will have to revise your topic, or at the very least, review this literature to identify something new to say about the problem. However, if it is someone else's particularly succinct expression, but it fits perfectly with what you are trying to say, then you can quote from the author directly, referencing the source. Identifying an author who has made the exact same point that you want to make can be an opportunity to add legitimacy to, as well as reinforce the significance of, the research problem you are investigating. The key is to build on that idea in new and innovative ways. If you are not sure how to do this, consult with a librarian .

6. Should I cite a source even if it was published long ago? Any source used in writing your paper should be cited, regardless of when it was written. However, in building a case for understanding prior research about your topic, it is generally true that you should focus on citing more recently published studies because they presumably have built upon the research of older studies. When referencing prior studies, use the research problem as your guide when considering what to cite. If a study from forty years ago investigated the same topic, it probably should be examined and considered in your list of references because the research may have been foundational or groundbreaking at the time, even if its findings are no longer relevant to current conditions or reflect current thinking [one way to determine if a study is foundational or groundbreaking is to examine how often it has been cited in recent studies using the "Cited by" feature of Google Scholar ]. However, if an older study only relates to the research problem tangentially or it has not been cited in recent studies, then it may be more appropriate to list it under further readings .

NOTE:   In any academic writing, you are required to identify which ideas, facts, thoughts, concepts, or declarative statements are yours and which are derived from the research of others. The only exception to this rule is information that is considered to be a commonly known fact [e.g., "George Washington was the first president of the United States"] or a statement that is self-evident [e.g., "Australia is a country in the Global South"]. Appreciate, however, that any "commonly known fact" is culturally constructed and shaped by social and aesthetical biases . If you are in doubt about whether or not a fact is considered to be widely understood knowledge, provide a supporting citation, or, ask your professor for clarification about how the statement should be cited.

Ballenger, Bruce P. The Curious Researcher: A Guide to Writing Research Papers . 7th edition. Boston, MA: Pearson, 2012; Blum, Susan Debra. My Word!: Plagiarism and College Culture . Ithaca, NY: Cornell University Press, 2009; Bretag, Tracey., editor. Handbook of Academic Integrity . Singapore: Springer Singapore, 2020; Carlock, Janine. Developing Information Literacy Skills: A Guide to Finding, Evaluating, and Citing Sources . Ann Arbor, MI: University of Michigan Press, 2020; Harvard Guide to Using Sources. Harvard College Writing Program. Harvard University; How to Cite Other Sources in Your Paper. The Structure, Format, Content, and Style of a Journal-Style Scientific Paper. Department of Biology. Bates College; Lunsford, Andrea A. and Robert Connors; The St. Martin's Handbook . New York: St. Martin's Press, 1989; Mills, Elizabeth Shown. Evidence Explained: Citing History Sources from Artifacts to Cyberspace . 3rd edition. Baltimore, MD: Genealogical Publishing Company, 2015; Research and Citation Resources. The Writing Lab and The OWL. Purdue University; Writing Tutorial Services, Center for Innovative Teaching and Learning. Indiana University; Why Cite? Poorvu Center for Teaching and Learning, Yale Univeraity.

Other Citation Research Guides

The following USC Libraries research guide can help you properly cite sources in your research paper:

• Citation Guide

The following USC Libraries research guide offers basic information on using images and media in research:

Listed below are particularly well-done and comprehensive websites that provide specific examples of how to cite sources under different style guidelines.

• Purdue University Online Writing Lab
• Southern Cross University Harvard Referencing Style
• University of Wisconsin Writing Center

This is a useful guide concerning how to properly cite images in your research paper.

• Colgate Visual Resources Library, Citing Images

This guide provides good information on the act of citation analysis, whereby you count the number of times a published work is cited by other works in order to measure the impact of a publication or author.

Measuring Your Impact: Impact Factor, Citation Analysis, and other Metrics: Citation Analysis [Sandy De Groote, University of Illinois, Chicago]

Automatic Citation Generators

The links below lead to systems where you can type in your information and have a citation compiled for you. Note that these systems are not foolproof so it is important that you verify that the citation is correct and check your spelling, capitalization, etc. However, they can be useful in creating basic types of citations, particularly for online sources.

• BibMe -- APA, MLA, Chicago, and Turabian styles
• DocsCite -- for citing government publications in APA or MLA formats
• EasyBib -- APA, MLA, and Chicago styles
• Son of Citation Machine -- APA, MLA, Chicago, and Turabian styles

NOTE:   Many companies that create the research databases the USC Libraries subscribe to, such as ProQuest , include built-in citation generators that help take the guesswork out of how to properly cite a work. When available, you should always utilize these features because they not only generate a citation to the source [e.g., a journal article], but include information about where you accessed the source [e.g., the database].

• << Previous: Writing Concisely
• Next: Avoiding Plagiarism >>
• Last Updated: Mar 19, 2024 11:03 AM
• URL: https://libguides.usc.edu/writingguide

Citation Help

What are citations, what is citing why is it important.

• Chicago Style
• Citation and Reference Tools
• Citations in Databases

Get help from a Librarian!

You can get help with your research, even when you can't come to campus!

Use the icon above to contact a reference librarian by chat or email. If chat is not available at the moment, email [email protected] , and a librarian will respond as quickly as possible.  Please allow at least 48 hours for responses to emails!

A citation , in college reading, writing, or speaking, is a reference to a source of information. The goal of all citations is to allow the audience (whether reading or listening) to identify and find the source of your information.  There are several different ways that information can be cited:

• In-text citation s are short notes that must be included with your text where the idea, data, or evidence from that source is used. In-text citations should match to a complete list of full citations, usually included as the last page of your paper.
• Verbal citations should be provided when you are giving a speech. You will need to mention the author and something about why the author is worthy of citing.
• Full citations provide all of the elements necessary for the reader to find the exact same source used by the writer. Full citations should be provided  for all the sources used or consulted in your research project. This will usually be in a list at the end of your paper called either a Works Cited list or References page.  It may also be on a separate sheet for speeches.

There are a variety of different formats that can be used for citations - MLA and APA are the two most commonly used at CR, but many other specialized styles exist as well.  Consult your assignment handout or ask your instructor which citation format you will be required to use. 

All citation styles will require you to include important elements from your source so that the reader can find that exact same source. Some of these important elements are author, title, publisher, place of publication, date of publication. APA and MLA styles format the citation elements slightly differently. Select the tab at the top of this guide for the style you need to find instructions, examples, and a PDF handout for that citation style that you can print.

• Next: MLA Style >>
• Last Updated: Feb 1, 2024 2:48 PM
• URL: https://redwoods.libguides.com/citations

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, automatically generate references for free.

• Knowledge Base
• Referencing

A Quick Guide to Harvard Referencing | Citation Examples

Published on 14 February 2020 by Jack Caulfield . Revised on 15 September 2023.

Referencing is an important part of academic writing. It tells your readers what sources you’ve used and how to find them.

Harvard is the most common referencing style used in UK universities. In Harvard style, the author and year are cited in-text, and full details of the source are given in a reference list .

Harvard Reference Generator

Instantly correct all language mistakes in your text

Be assured that you'll submit flawless writing. Upload your document to correct all your mistakes.

Table of contents

Harvard in-text citation, creating a harvard reference list, harvard referencing examples, referencing sources with no author or date, frequently asked questions about harvard referencing.

A Harvard in-text citation appears in brackets beside any quotation or paraphrase of a source. It gives the last name of the author(s) and the year of publication, as well as a page number or range locating the passage referenced, if applicable:

Note that ‘p.’ is used for a single page, ‘pp.’ for multiple pages (e.g. ‘pp. 1–5’).

An in-text citation usually appears immediately after the quotation or paraphrase in question. It may also appear at the end of the relevant sentence, as long as it’s clear what it refers to.

When your sentence already mentions the name of the author, it should not be repeated in the citation:

Sources with multiple authors

When you cite a source with up to three authors, cite all authors’ names. For four or more authors, list only the first name, followed by ‘ et al. ’:

Sources with no page numbers

Some sources, such as websites , often don’t have page numbers. If the source is a short text, you can simply leave out the page number. With longer sources, you can use an alternate locator such as a subheading or paragraph number if you need to specify where to find the quote:

Multiple citations at the same point

When you need multiple citations to appear at the same point in your text – for example, when you refer to several sources with one phrase – you can present them in the same set of brackets, separated by semicolons. List them in order of publication date:

Multiple sources with the same author and date

If you cite multiple sources by the same author which were published in the same year, it’s important to distinguish between them in your citations. To do this, insert an ‘a’ after the year in the first one you reference, a ‘b’ in the second, and so on:

Prevent plagiarism, run a free check.

A bibliography or reference list appears at the end of your text. It lists all your sources in alphabetical order by the author’s last name, giving complete information so that the reader can look them up if necessary.

The reference entry starts with the author’s last name followed by initial(s). Only the first word of the title is capitalised (as well as any proper nouns).

Sources with multiple authors in the reference list

As with in-text citations, up to three authors should be listed; when there are four or more, list only the first author followed by ‘ et al. ’:

Reference list entries vary according to source type, since different information is relevant for different sources. Formats and examples for the most commonly used source types are given below.

• Entire book
• Book chapter
• Translated book
• Edition of a book

Journal articles

• Print journal
• Online-only journal with DOI
• Online-only journal with no DOI
• General web page
• Online article or blog
• Social media post

Sometimes you won’t have all the information you need for a reference. This section covers what to do when a source lacks a publication date or named author.

No publication date

When a source doesn’t have a clear publication date – for example, a constantly updated reference source like Wikipedia or an obscure historical document which can’t be accurately dated – you can replace it with the words ‘no date’:

Note that when you do this with an online source, you should still include an access date, as in the example.

When a source lacks a clearly identified author, there’s often an appropriate corporate source – the organisation responsible for the source – whom you can credit as author instead, as in the Google and Wikipedia examples above.

When that’s not the case, you can just replace it with the title of the source in both the in-text citation and the reference list:

Harvard referencing uses an author–date system. Sources are cited by the author’s last name and the publication year in brackets. Each Harvard in-text citation corresponds to an entry in the alphabetised reference list at the end of the paper.

Vancouver referencing uses a numerical system. Sources are cited by a number in parentheses or superscript. Each number corresponds to a full reference at the end of the paper.

A Harvard in-text citation should appear in brackets every time you quote, paraphrase, or refer to information from a source.

The citation can appear immediately after the quotation or paraphrase, or at the end of the sentence. If you’re quoting, place the citation outside of the quotation marks but before any other punctuation like a comma or full stop.

In Harvard referencing, up to three author names are included in an in-text citation or reference list entry. When there are four or more authors, include only the first, followed by ‘ et al. ’

Though the terms are sometimes used interchangeably, there is a difference in meaning:

• A reference list only includes sources cited in the text – every entry corresponds to an in-text citation .
• A bibliography also includes other sources which were consulted during the research but not cited.

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the ‘Cite this Scribbr article’ button to automatically add the citation to our free Reference Generator.

Caulfield, J. (2023, September 15). A Quick Guide to Harvard Referencing | Citation Examples. Scribbr. Retrieved 20 March 2024, from https://www.scribbr.co.uk/referencing/harvard-style/

Is this article helpful?

Jack Caulfield

Other students also liked, harvard in-text citation | a complete guide & examples, harvard style bibliography | format & examples, referencing books in harvard style | templates & examples, scribbr apa citation checker.

An innovative new tool that checks your APA citations with AI software. Say goodbye to inaccurate citations!

University of Pittsburgh Library System

• Collections

Course & Subject Guides

Citation styles: apa, mla, chicago, turabian, ieee.

• APA 7th Edition
• Turabian 9th
• Writing & Citing Help
• Understanding Plagiarism

Quick Links

Listed below are a few quick links to resources that will aid you in citing sources.

• Sign up for a Mendeley, EndNote, or Zotero training class.
• APA 7th Edition Published in October 2019. Visit this page for links to resources and examples.
• MLA Need help with citing MLA style? Find information here along with links to books in PittCat and free online resources.
• Chicago/Turabian Need help with citing Chicago/Turabian style? Find examples here along with links to the online style manual and free online resources.

Getting Started: How to use this guide

This LibGuide was designed to provide you with assistance in citing your sources when writing an academic paper.

There are different styles which format the information differently. In each tab, you will find descriptions of each citation style featured in this guide along with links to online resources for citing and a few examples.

What is a citation and citation style?

A citation is a way of giving credit to individuals for their creative and intellectual works that you utilized to support your research. It can also be used to locate particular sources and combat plagiarism. Typically, a citation can include the author's name, date, location of the publishing company, journal title, or DOI (Digital Object Identifier).

A citation style dictates the information necessary for a citation and how the information is ordered, as well as punctuation and other formatting.

How to do I choose a citation style?

There are many different ways of citing resources from your research. The citation style sometimes depends on the academic discipline involved. For example:

• APA (American Psychological Association) is used by Education, Psychology, and Sciences
• MLA (Modern Language Association) style is used by the Humanities
• Chicago/Turabian style is generally used by Business, History, and the Fine Arts

*You will need to consult with your professor to determine what is required in your specific course.

Click the links below to find descriptions of each style along with a sample of major in-text and bibliographic citations, links to books in PittCat, online citation manuals, and other free online resources.

• APA Citation Style
• MLA Citation Style
• Chicago/Turabian Citation Style
• Tools for creating bibliographies (CItation Managers)

Writing Centers

Need someone to review your paper? Visit the Writing Center or Academic Success Center on your campus.

• Oakland Campus
• Greensburg Campus
• Johnstown Campus
• Titusville Campus
• Bradford Campus
• Next: APA 7th Edition >>
• Last Updated: Apr 27, 2023 10:27 AM
• URL: https://pitt.libguides.com/citationhelp

Purdue Online Writing Lab Purdue OWL® College of Liberal Arts

In-Text Citations: The Basics

Welcome to the Purdue OWL

This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.

Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.

Note:  This page reflects the latest version of the APA Publication Manual (i.e., APA 7), which released in October 2019. The equivalent resource for the older APA 6 style  can be found here .

Reference citations in text are covered on pages 261-268 of the Publication Manual. What follows are some general guidelines for referring to the works of others in your essay.

Note:  On pages 117-118, the Publication Manual suggests that authors of research papers should use the past tense or present perfect tense for signal phrases that occur in the literature review and procedure descriptions (for example, Jones (1998)  found  or Jones (1998)  has found ...). Contexts other than traditionally-structured research writing may permit the simple present tense (for example, Jones (1998)  finds ).

APA Citation Basics

When using APA format, follow the author-date method of in-text citation. This means that the author's last name and the year of publication for the source should appear in the text, like, for example, (Jones, 1998). One complete reference for each source should appear in the reference list at the end of the paper.

If you are referring to an idea from another work but  NOT  directly quoting the material, or making reference to an entire book, article or other work, you only have to make reference to the author and year of publication and not the page number in your in-text reference.

On the other hand, if you are directly quoting or borrowing from another work, you should include the page number at the end of the parenthetical citation. Use the abbreviation “p.” (for one page) or “pp.” (for multiple pages) before listing the page number(s). Use an en dash for page ranges. For example, you might write (Jones, 1998, p. 199) or (Jones, 1998, pp. 199–201). This information is reiterated below.

Regardless of how they are referenced, all sources that are cited in the text must appear in the reference list at the end of the paper.

In-text citation capitalization, quotes, and italics/underlining

• Always capitalize proper nouns, including author names and initials: D. Jones.
• If you refer to the title of a source within your paper, capitalize all words that are four letters long or greater within the title of a source:  Permanence and Change . Exceptions apply to short words that are verbs, nouns, pronouns, adjectives, and adverbs:  Writing New Media ,  There Is Nothing Left to Lose .

( Note:  in your References list, only the first word of a title will be capitalized:  Writing new media .)

• When capitalizing titles, capitalize both words in a hyphenated compound word:  Natural-Born Cyborgs .
• Capitalize the first word after a dash or colon: "Defining Film Rhetoric: The Case of Hitchcock's  Vertigo ."
• If the title of the work is italicized in your reference list, italicize it and use title case capitalization in the text:  The Closing of the American Mind ;  The Wizard of Oz ;  Friends .
• If the title of the work is not italicized in your reference list, use double quotation marks and title case capitalization (even though the reference list uses sentence case): "Multimedia Narration: Constructing Possible Worlds;" "The One Where Chandler Can't Cry."

Short quotations

If you are directly quoting from a work, you will need to include the author, year of publication, and page number for the reference (preceded by "p." for a single page and “pp.” for a span of multiple pages, with the page numbers separated by an en dash).

You can introduce the quotation with a signal phrase that includes the author's last name followed by the date of publication in parentheses.

If you do not include the author’s name in the text of the sentence, place the author's last name, the year of publication, and the page number in parentheses after the quotation.

Long quotations

Place direct quotations that are 40 words or longer in a free-standing block of typewritten lines and omit quotation marks. Start the quotation on a new line, indented 1/2 inch from the left margin, i.e., in the same place you would begin a new paragraph. Type the entire quotation on the new margin, and indent the first line of any subsequent paragraph within the quotation 1/2 inch from the new margin. Maintain double-spacing throughout, but do not add an extra blank line before or after it. The parenthetical citation should come after the closing punctuation mark.

Because block quotation formatting is difficult for us to replicate in the OWL's content management system, we have simply provided a screenshot of a generic example below.

Formatting example for block quotations in APA 7 style.

Quotations from sources without pages

Direct quotations from sources that do not contain pages should not reference a page number. Instead, you may reference another logical identifying element: a paragraph, a chapter number, a section number, a table number, or something else. Older works (like religious texts) can also incorporate special location identifiers like verse numbers. In short: pick a substitute for page numbers that makes sense for your source.

Summary or paraphrase

If you are paraphrasing an idea from another work, you only have to make reference to the author and year of publication in your in-text reference and may omit the page numbers. APA guidelines, however, do encourage including a page range for a summary or paraphrase when it will help the reader find the information in a longer work. 

What Are Citations?

After completing this tutorial, you will be able to:.

Navigate using your keyboard's left and right arrows or use the navigation links at the bottom of the screen. Pressing escape on your keyboard will show a slide view.

Continue with the tutorial

Last updated April 2018

Why Are Citations Important?

What Does a Citation Look Like?

A citation is typically found in two places:, in-text citations.

Reference Lists/Bibliographies

Authors use in-text citations after they have paraphrased, summarized, quoted or otherwise used another author’s work. Examples of in-text citations include parentheses, footnotes or endnotes.

Reference Lists

A reference list includes information on all of the sources an author used. It can also be called a bibliography or works cited. Each item in the list includes information such as title, author and publication date. A reference list is usually listed at the end of a paper with the exception of footnotes which are at the bottom of each page.

Reading a Citation

Knowing how to read a citation in a reference list or bibliography will help you identify different types of sources that an author used in their research. You can use a reference list from another researcher to find related sources on your topic, or to find counterpoints to your research. Let’s look at citations for three common types of sources:

Reading Citations: Article Citations

A citation for an article can include:.

Why is this important?

The journal title is often what is listed in library catalogs.

How do you know if it is an article?

The presence of two titles (article and journal) are the biggest clue that this is an article. Volume Number and Issue Number are also big clues as books will not have those pieces in a citation.

Reading Citations: Book Citations

A citation for a book can include:.

Year, edition, format, and publisher help distinguish between versions.

How do you know if it is a book?

Reading Citations: Website Citations

A citation for a website can include:.

To find and verify a website, you need to know the URL. Since websites change frequently, knowing the date accessed is similar to knowing a publication date.

How do you know if it is a website?

The date accessed and the presence of a URL are the biggest clues that you are looking at a citation for a website.

Citation Styles

Different disciplines cite in different ways which means that there are many different citation styles.

Your professor or department will tell you what style to use.

Style guides, manuals and handbooks are available both in print and online.

Citation Guides at the University Libraries

Examples of Citation Styles: Article Citations

Examples of Citation Styles: Book Citations

Knowledge Check

What are citations review, you are now able to:, do you have questions.

Design and content by the University of Minnesota Libraries Instructional Design Team: Lindsay Matts-Benson and Andrew Palahniuk. For accessibility accommodations, or to receive this information in alternative formats, contact [email protected] or 612-624-0365. The content in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License . Some images are copyright.

• Directories
• What are citations and why should I use them?

When should I use a citation?

• Why are there so many citation styles?
• Which citation style should I use?
• Chicago Notes Style
• Chicago Author-Date Style
• AMA Style (medicine)
• Bluebook (law)
• Additional Citation Styles
• Built-in Citation Tools
• Quick Citation Generators
• Citation Management Software
• Start Your Research
• Research Guides
• University of Washington Libraries
• Library Guides
• UW Libraries
• Citing Sources

Citing Sources: When should I use a citation?

A citation should be used when content that did not originate with you is used to support your writing.

Content includes:

• words (quotations, phrases, sayings, etc.)
• thoughts or ideas (summarizations and paraphrases)
• audio or visual material (photos, videos, screencaptures, powerpoint slides, social media content, audio recordings, etc.)

Here are a few pages fr om Excelsior OWL's guide to writing process to get you started:

• Summarizing sources
• Paraphrasing sources
• Using quotations

What you don't need to cite

No need to cite what is known as common knowledge.

But, what is common knowledge?  Common knowledge includes information that someone can easily trace and find the answer to.  In an academic context, common knowledge will depend on the audience, but here are some examples to get you started:

• There are 24 hours in a day.
• The President of the United States can serve up to two terms in office, each term lasting four years.
• The phone number for emergency services in the United States is 9-1-1

For more examples of how to determine if something is common knowledge, check out this resource :

• Common Knowledge & Plagiarism from Excelsior OWL

When in doubt: CITE --  You won’t be judged harshly for adding a citation when it isn’t needed.  However, skipping a citation (whether it’s an accident or not) is considered plagiarism, which can have serious consequences.

• << Previous: What are citations and why should I use them?
• Next: Why are there so many citation styles? >>
• Last Updated: Oct 24, 2023 3:46 PM
• URL: https://guides.lib.uw.edu/research/citations

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• 04 March 2024
• Clarification 05 March 2024

Millions of research papers at risk of disappearing from the Internet

You can also search for this author in PubMed   Google Scholar

You have full access to this article via your institution.

A study identified more than two million articles that did not appear in a major digital archive, despite having an active DOI. Credit: Anna Berkut/Alamy

More than one-quarter of scholarly articles are not being properly archived and preserved, a study of more than seven million digital publications suggests. The findings, published in the Journal of Librarianship and Scholarly Communication on 24 January 1 , indicate that systems to preserve papers online have failed to keep pace with the growth of research output.

“Our entire epistemology of science and research relies on the chain of footnotes,” explains author Martin Eve, a researcher in literature, technology and publishing at Birkbeck, University of London. “If you can’t verify what someone else has said at some other point, you’re just trusting to blind faith for artefacts that you can no longer read yourself.”

Eve, who is also involved in research and development at digital-infrastructure organization Crossref, checked whether 7,438,037 works labelled with digital object identifiers (DOIs) are held in archives. DOIs — which consist of a string of numbers, letters and symbols — are unique fingerprints used to identify and link to specific publications, such as scholarly articles and official reports. Crossref is the largest DOI registration agency, allocating the identifiers to about 20,000 members, including publishers, museums and other institutions.

The sample of DOIs included in the study was made up of a random selection of up to 1,000 registered to each member organization. Twenty-eight per cent of these works — more than two million articles — did not appear in a major digital archive, despite having an active DOI. Only 58% of the DOIs referenced works that had been stored in at least one archive. The other 14% were excluded from the study because they were published too recently, were not journal articles or did not have an identifiable source.

Preservation challenge

Eve notes that the study has limitations: namely that it tracked only articles with DOIs, and that it did not search every digital repository for articles (he did not check whether items with a DOI were stored in institutional repositories, for example).

Nevertheless, preservation specialists have welcomed the analysis. “It’s been hard to know the real extent of the digital preservation challenge faced by e-journals,” says William Kilbride, managing director of the Digital Preservation Coalition, headquartered in York, UK. The coalition publishes a handbook detailing good preservation practice.

“Many people have the blind assumption that if you have a DOI, it’s there forever,” says Mikael Laakso, who studies scholarly publishing at the Hanken School of Economics in Helsinki. “But that doesn’t mean that the link will always work.” In 2021, Laakso and his colleagues reported 2 that more than 170 open-access journals had disappeared from the Internet between 2000 and 2019.

Kate Wittenberg, managing director of the digital archiving service Portico in New York City, warns that small publishers are at higher risk of failing to preserve articles than are large ones. “It costs money to preserve content,” she says, adding that archiving involves infrastructure, technology and expertise that many smaller organizations do not have access to.

Eve’s study suggests some measures that could improve digital preservation, including stronger requirements at DOI registration agencies and better education and awareness of the issue among publishers and researchers.

“Everybody thinks of the immediate gains they might get from having a paper out somewhere, but we really should be thinking about the long-term sustainability of the research ecosystem,” Eve says. “After you’ve been dead for 100 years, are people going to be able to get access to the things you’ve worked on?”

Nature 627 , 256 (2024)

doi: https://doi.org/10.1038/d41586-024-00616-5

Updates & Corrections

Clarification 05 March 2024 : The headline of this story has been edited to reflect the fact that some of these papers have not entirely disappeared from the Internet. Rather, many papers are still accessible but have not been properly archived.

Eve, M. P. J. Libr. Sch. Commun. 12 , eP16288 (2024).

Article   Google Scholar  

Laakso, M., Matthias, L. & Jahn, N. J. Assoc. Inf. Sci. Technol. 72 , 1099–1112 (2021).

Download references

Reprints and permissions

• Information technology
• Scientific community

AI image generators often give racist and sexist results: can they be fixed?

News Feature 19 MAR 24

Why scientists trust AI too much — and what to do about it

Editorial 06 MAR 24

Gender bias is more exaggerated in online images than in text

News & Views 14 FEB 24

Meaningfulness in a scientific career is about more than tangible outputs

Correspondence 19 MAR 24

So … you’ve been hacked

Technology Feature 19 MAR 24

‘Global swimways’ on free-flowing rivers will protect key migratory fish species

Peer-replication model aims to address science’s ‘reproducibility crisis’

Nature Index 13 MAR 24

Numbers highlight US dominance in clinical research

Embrace AI to break down barriers in publishing for people who aren’t fluent in English

Correspondence 12 MAR 24

Chair Professor Positions in the School of Pharmaceutical Science and Technology

SPST seeks top Faculty scholars in Pharmaceutical Sciences.

Tianjin, China

Tianjin University (TJU)

Chair Professor Positions in the School of Materials Science and Engineering

SMSE consists of materials science-related majors and research, including metallic materials, ceramic materials, polymeric materials...

Chair Professor Positions in the School of Mechanical Engineering

Aims to cultivate top talents, train a top-ranking faculty team, construct first-class disciplines and foster a favorable academic environment.

Chair Professor Positions in the School of Precision Instruments and Optoelectronic Engineering

We are committed to accomplishing the mission of achieving a world-top-class engineering school.

Chair Professor Positions in the School of Earth System Science

Seeks for applicants in the following or related fields: Earth System Process/Simulation/Governance, Big Data and Smart Geography...

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

This paper is in the following e-collection/theme issue:

Published on 18.3.2024 in Vol 10 (2024)

Predicting COVID-19 Vaccination Uptake Using a Small and Interpretable Set of Judgment and Demographic Variables: Cross-Sectional Cognitive Science Study

Authors of this article:

Original Paper

• Nicole L Vike 1 , PhD   ; 
• Sumra Bari 1 , PhD   ; 
• Leandros Stefanopoulos 2, 3 * , MSc   ; 
• Shamal Lalvani 2 * , MSc   ; 
• Byoung Woo Kim 1 * , MSc   ; 
• Nicos Maglaveras 3 , PhD   ; 
• Martin Block 4 , PhD   ; 
• Hans C Breiter 1, 5 , MD   ; 
• Aggelos K Katsaggelos 2, 6, 7 , PhD  

1 Department of Computer Science, University of Cincinnati, Cincinnati, OH, United States

2 Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States

3 School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece

4 Integrated Marketing Communications, Medill School, Northwestern University, Evanston, IL, United States

5 Department of Psychiatry, Massachusetts General Hospital, Harvard School of Medicine, Boston, MA, United States

6 Department of Computer Science, Northwestern University, Evanston, IL, United States

7 Department of Radiology, Northwestern University, Evanston, IL, United States

*these authors contributed equally

Corresponding Author:

Hans C Breiter, MD

Department of Computer Science

University of Cincinnati

2901 Woodside Drive

Cincinnati, OH, 45219

United States

Phone: 1 617 413 0953

Email: [email protected]

Background: Despite COVID-19 vaccine mandates, many chose to forgo vaccination, raising questions about the psychology underlying how judgment affects these choices. Research shows that reward and aversion judgments are important for vaccination choice; however, no studies have integrated such cognitive science with machine learning to predict COVID-19 vaccine uptake .

Objective: This study aims to determine the predictive power of a small but interpretable set of judgment variables using 3 machine learning algorithms to predict COVID-19 vaccine uptake and interpret what profile of judgment variables was important for prediction.

Methods: We surveyed 3476 adults across the United States in December 2021. Participants answered demographic, COVID-19 vaccine uptake (ie, whether participants were fully vaccinated), and COVID-19 precaution questions. Participants also completed a picture-rating task using images from the International Affective Picture System. Images were rated on a Likert-type scale to calibrate the degree of liking and disliking. Ratings were computationally modeled using relative preference theory to produce a set of graphs for each participant (minimum R 2 >0.8). In total, 15 judgment features were extracted from these graphs, 2 being analogous to risk and loss aversion from behavioral economics. These judgment variables, along with demographics, were compared between those who were fully vaccinated and those who were not. In total, 3 machine learning approaches (random forest, balanced random forest [BRF], and logistic regression) were used to test how well judgment, demographic, and COVID-19 precaution variables predicted vaccine uptake . Mediation and moderation were implemented to assess statistical mechanisms underlying successful prediction.

Results: Age, income, marital status, employment status, ethnicity, educational level, and sex differed by vaccine uptake (Wilcoxon rank sum and chi-square P <.001). Most judgment variables also differed by vaccine uptake (Wilcoxon rank sum P <.05). A similar area under the receiver operating characteristic curve (AUROC) was achieved by the 3 machine learning frameworks, although random forest and logistic regression produced specificities between 30% and 38% (vs 74.2% for BRF), indicating a lower performance in predicting unvaccinated participants. BRF achieved high precision (87.8%) and AUROC (79%) with moderate to high accuracy (70.8%) and balanced recall (69.6%) and specificity (74.2%). It should be noted that, for BRF, the negative predictive value was <50% despite good specificity. For BRF and random forest, 63% to 75% of the feature importance came from the 15 judgment variables. Furthermore, age, income, and educational level mediated relationships between judgment variables and vaccine uptake .

Conclusions: The findings demonstrate the underlying importance of judgment variables for vaccine choice and uptake, suggesting that vaccine education and messaging might target varying judgment profiles to improve uptake. These methods could also be used to aid vaccine rollouts and health care preparedness by providing location-specific details (eg, identifying areas that may experience low vaccination and high hospitalization).

Introduction

In early 2020, the COVID-19 pandemic wreaked havoc worldwide, triggering rapid vaccine development efforts. Despite federal, state, and workplace vaccination mandates, many individuals made judgments against COVID-19 vaccination, leading researchers to study the psychology underlying individual vaccination preferences and what might differentiate the framework for judgment between individuals who were fully vaccinated against COVID-19 and those who were not (henceforth referred to as vaccine uptake ). A better understanding of these differences in judgment may highlight targets for public messaging and education to increase the incidence of choosing vaccination.

Multiple studies have sought to predict an individual’s intention to receive a COVID-19 vaccine or specific variables underlying vaccination choices or mitigation strategies [ 1 - 7 ], but few have predicted vaccine uptake . One such study used 83 sociodemographic variables (with education, ethnicity, internet access, income, longitude, and latitude being the most important predictors) to predict vaccine uptake with 62% accuracy [ 8 ], confirming both the importance and limitations of these variables in prediction models. Other studies have compared demographic groups between vaccinated and nonvaccinated persons; Bulusu et al [ 9 ] found that young adults (aged 18-35 years), women, and those with higher levels of education had higher odds of being vaccinated. In a study of >12 million persons, the largest percentage of those who initiated COVID-19 vaccination were White, non-Hispanic women between the ages of 50 and 64 years [ 10 ]. Demographic variables are known to affect how individuals judge what is rewarding or aversive [ 11 , 12 ] yet are not themselves variables quantifying how individuals make judgments that then frame decisions.

Judgment reflects an individual’s preferences, or the variable extent to which they approach or avoid events in the world based on the rewarding or aversive effects of these events [ 13 - 15 ]. The definition of preference in psychology differs from that in economics. In psychology, preferences are associated with “wanting” and “liking” and are framed by judgments that precede decisions, which can be quantified through reinforcement reward or incentive reward tasks [ 12 , 16 - 21 ]. In economics, preferences are relations derived from consumer choice data (refer to the axioms of revealed preference [ 22 ]) and reflect choices or decisions based on judgments that place value on behavioral options. Economist Paul Samuelson noted that decisions are “assumed to be correlative to desire or want” [ 23 ]. In this study, we focused on a set of variables that frame judgment, with the presumption that judgments precede choices [ 12 , 20 ]. Variables that frame judgment can be derived from tasks using operant key-pressing tasks that quantify “wanting” [ 24 - 33 ] or simple rating tasks that are analogous to “liking” [ 20 , 34 ]. Both operant keypress and rating tasks measure variables that quantify the average (mean) magnitude ( K ), variance ( σ ), and pattern (ie, Shannon entropy [ H ]) of reward and aversion judgments [ 35 ]. We refer to this methodology and the multiple relationships between these variables and features based on their graphical relationships as relative preference theory (RPT; Figure 1 ) [ 18 , 36 ]. RPT has been shown to produce discrete, recurrent, robust, and scalable relationships between judgment variables [ 37 ] that produce mechanistic models for prediction [ 33 ], and which have demonstrated relationships to brain circuitry [ 24 - 27 , 30 ] and psychiatric illness [ 28 ]. Of the graphs produced for RPT, 2 appear to resemble graphs derived with different variables in economics, namely, prospect theory [ 38 ] and the mean-variance function for portfolio theory described by Markowitz [ 39 ]. Given this graphical resemblance, it is important to note that RPT functions quantifying value are not the same as standard representations of preference in economics. Behavioral economic variables such as loss aversion and risk aversion [ 38 , 40 - 51 ] are not to be interpreted in the same context given that both reflect biases and bounds to human rationality. In psychology, they are grounded in judgments that precede decisions, whereas in economics, they are grounded in consumer decisions themselves. Going forward, we will focus on judgment-based loss aversion, representing the overweighting of negative judgments relative to positive ones, and judgment-based risk aversion, representing the preference for small but certain assessments over larger but less certain ones (ie, assessments that have more variance associated with them) [ 38 , 40 - 51 ]. Herein, loss aversion and risk aversion refer to ratings or judgments that precede decisions.

A number of studies have described how risk aversion and other judgment variables are important for individual vaccine choices and hesitancies [ 52 - 58 ]. Hudson and Montelpare [ 54 ] found that risk aversion may promote vaccine adherence when people perceive contracting a disease as more dangerous or likely. Trueblood et al [ 52 ] noticed that those who were more risk seeking (as measured via a gamble ladder task) were more likely to receive the vaccine even if the vaccine was described as expedited. Wagner et al [ 53 ] described how risk misperceptions (when the actual risk does not align with the perceived risk) may result from a combination of cognitive biases, including loss aversion. A complex theoretical model using historical vaccine attitudes grounded in decision-making has also been proposed to predict COVID-19 vaccination, but this model has not yet been tested [ 59 ]. To our knowledge, no study has assessed how well a model comprising variables that reflect reward and aversion judgments predicts vaccine uptake .

Goal of This Study

Given the many vaccine-related issues that occurred during the COVID-19 pandemic (eg, vaccine shortages, hospital overload, and vaccination resistance or hesitancy), it is critical to develop methods that might improve planning around such shortcomings. Because judgment variables are fundamental to vaccine choice, they provide a viable target for predicting vaccine uptake . In addition, the rating methodology used to quantify variables of judgment is independent of methods quantifying vaccine uptake or intent to vaccinate, limiting response biases within the study data.

In this study, we aimed to predict COVID-19 vaccine uptake using judgment, demographic, and COVID-19 precaution (ie, behaviors minimizing potential exposure to COVID-19) variables using multiple machine learning algorithms, including logistic regression, random forest, and balanced random forest (BRF). BRF was hypothesized to perform best given its potential benefits with handling class imbalances [ 60 ], balancing both recall and specificity, and producing Gini scores that provide relative variable importance to prediction. In this study, the need for data imbalance techniques was motivated by the importance of the specificity metric, which would reflect the proportion of participants who did not receive full vaccination; without balancing, the model might not achieve similar recall and specificity values. When there is a large difference between recall and specificity, specificity might instead reflect the size of the minority class (those who did not receive full vaccination). In general, random forest approaches have been reported to have benefits over other approaches such as principal component analysis and neural networks, in which the N-dimensional feature space or layers (in the case of neural networks) are complex nonlinear functions, making it difficult to interpret variable importance and relationships to the outcome variable. To provide greater certainty about these assumptions, we performed logistic regression in parallel with random forest and BRF. The 3 machine learning approaches used a small feature set (<20) with interpretable relationships to the predicted variable. Such interpretations may not be achievable in big data approaches that use hundreds to thousands of variables that seemingly add little significance to the prediction models. Interpretation was facilitated by (1) the Gini importance criterion associated with BRF and random forest, which provided a profile of the judgment variables most important for prediction; and (2) mediation and moderation analyses that offered insights into statistical mechanisms among judgment variables, demographic (contextual) variables, and vaccine uptake . Determining whether judgment variables are predictive of COVID-19 vaccine uptake and defining which demographic variables facilitate this prediction presents a number of behavioral targets for vaccine education and messaging—and potentially identifies actionable targets for increasing vaccine uptake .

More broadly, the prediction of vaccine uptake may aid (1) vaccine supply chain and administration logistics by indicating areas that may need more or fewer vaccines, (2) targeted governmental messaging to locations with low predicted uptake, and (3) preparation of areas that may experience high cases of infection that could ultimately impact health care preparedness and infrastructure. The proposed method could also be applied to other mandated or government-recommended vaccines (eg, influenza and human papillomavirus) to facilitate the aforementioned logistics. Locally, vaccine uptake prediction could facilitate local messaging and prepare health care institutions for vaccine rollout and potential hospital overload. Nationally, prediction might inform public health officials and government communication bodies that are responsible for messaging and vaccine rollout with the goal of improving vaccine uptake and limiting infection and hospital overload.

Recruitment

Similar recruitment procedures for a smaller population-based study have been described previously [ 61 - 63 ]. In this study, participants were randomly sampled from the general US population using an email survey database used by Gold Research, Inc. Gold Research administered questionnaires in December 2021 using recruitment formats such as (1) customer databases from large companies that participate in revenue-sharing agreements, (2) social media, and (3) direct mail. Recruited participants followed a double opt-in consent procedure that included primary participation in the study as well as secondary use of anonymized, deidentified data (ie, all identifying information was removed by Gold Research before retrieval by the research group) in secondary analyses (refer to the Ethical Considerations section for more detail). During consent procedures, participants provided demographic information (eg, age, race, and sex) to ensure that the sampled participants adequately represented the US census at the time of the survey (December 2021). Respondents were also presented with repeated test questions to screen out those providing random and illogical responses or showing flatline or speeder behavior. Participants who provided such data were flagged, and their data were removed.

Because other components of the survey required an adequate sample of participants with mental health conditions, Gold Research oversampled 15% (60,000/400,000) of the sample for mental health conditions, and >400,000 respondents were contacted to complete the questionnaire. Gold Research estimated that, of the 400,000 participants, >300,000 (>75%) either did not respond or declined to participate. Of the remaining 25% (100,000/400,000) who clicked on the survey link, >50% (52,000/100,000) did not fully complete the questionnaire. Of the ≥48,000 participants who completed the survey (ie, ≥48,000/400,000, ≥12% of the initial pool of queried persons), those who did not clear data integrity assessments were omitted. Participants who met quality assurance procedures (refer to the following section) were selected, with a limit of 4000 to 4050 total participants.

Eligible participants were required to be aged between 18 and 70 years at the time of the survey, comprehend the English language, and have access to an electronic device (eg, laptop or smartphone).

Ethical Considerations

All participants provided informed consent, which included their primary participation in the study as well as the secondary use of their anonymized, deidentified data (ie, all identifying information removed by Gold Research before retrieval by the research group) in secondary analyses. This study was approved by the Northwestern University institutional review board (approval STU00213665) for the initial project start and later by the University of Cincinnati institutional review board (approval 2023-0164) as some Northwestern University investigators moved to the University of Cincinnati. All study approvals were in accordance with the Declaration of Helsinki. All participants were compensated with US $10 for taking part. Detailed survey instructions have been published previously [ 61 - 63 ].

Quality Assurance and Data Exclusion

Three additional quality assurance measures were used to flag nonadhering participants: (1) participants who indicated that they had ≥10 clinician-diagnosed illnesses (refer to Figure S1 in Multimedia Appendix 1 [ 18 , 33 , 36 , 64 - 68 ] for a list), (2) participants who showed minimal variance in the picture-rating task (ie, all pictures were rated the same or the ratings varied only by 1 point; refer to the Picture-Rating Task section), and (3) inconsistencies between educational level and years of education and participants who completed the questionnaire in <800 seconds.

Data from 4019 participants who passed the initial data integrity assessments were anonymized and then sent to the research team. Data were further excluded if the quantitative feature set derived from the picture-rating task was incomplete or if there were extreme outliers (refer to the RPT Framework section). Using these exclusion criteria, of the 4019 participants, 3476 (86.49%) were cleared for statistical analysis, representing 0.87% (3476/400,000) of the initial recruitment pool. A flowchart of participant exclusion is shown in Figure 2 .

Questionnaire

Participants were asked to report their age, sex, ethnicity, annual household income, marital status, employment status, and educational level. Participants were asked to report whether they had received the full vaccination ( yes or no responses). At the time of the survey, participants were likely to have received either 2 doses of the Pfizer or Moderna vaccine or 1 dose of the Johnson & Johnson vaccine as per the Centers for Disease Control and Prevention guidelines. Participants were also asked to respond yes (they routinely followed the precaution) or no (they did not routinely follow the precaution) to 4 COVID-19 precaution behaviors: mask wearing, social distancing, washing or sanitizing hands, and not gathering in large groups (refer to Tables S1 and S2 in Multimedia Appendix 1 for the complete questions and sample sizes, respectively). In addition, participants completed a picture-rating task at 2 points during the survey (refer to the Picture-Rating Task section).

Picture-Rating Task

A picture-rating task was administered to quantify participants’ degree of liking and disliking a validated picture set using pictures calibrated over large samples for their emotional intensity and valence [ 69 , 70 ]. Ratings from this task have been mathematically modeled using RPT to define graphical features of reward and aversion judgments. Each feature quantifies a core aspect of judgment, including risk aversion and loss aversion. Judgment variables have been shown to meet the criteria for lawfulness [ 37 ] that produce mechanistic models for prediction [ 33 ], with published relationships to brain circuitry [ 24 - 27 , 30 ] and psychiatric illness [ 28 ]. A more complete description of these judgment variables and their computation can be found in the RPT Framework section and in Table 1 .

For this task, participants were shown 48 unique color images from the International Affective Picture System [ 69 , 70 ]. A total of 6 picture categories were used: sports, disasters, cute animals, aggressive animals, nature (beach vs mountains), and men and women dressed minimally, with 8 pictures per category (48 pictures in total; Figure 1 A). These images have been used and validated in research on human emotion, attention, and preferences [ 69 , 70 ]. The images were displayed on the participants’ digital devices with a maximum size of 1204 × 768 pixels. Below each picture was a rating scale from −3 ( dislike very much ) to +3 ( like very much ), where 0 indicated indifference ( Figure 1 A). While there was no time limit for selecting a picture rating, participants were asked to rate the images as quickly as possible and use their first impression. Once a rating was selected, the next image was displayed.

RPT Framework

Ratings from the picture-rating task were analyzed using an RPT framework. This framework fits approach and avoidance curves and derives mathematical features from graphical plots ( Figures 1 B-1D). These methods have been described at length in prior work and are briefly described in this section [ 11 , 18 , 33 , 36 ]. More complete descriptions and quality assurance procedures can be found in Multimedia Appendix 1 .

At least 15 judgment variables can be mathematically derived from this framework and are psychologically interpretable; they have been validated using both operant keypress [ 9 , 25 - 27 ] and picture-rating tasks [ 11 , 34 ]. The 15 judgment variables are loss aversion, risk aversion, loss resilience, ante, insurance, peak positive risk, peak negative risk, reward tipping point, aversion tipping point, total reward risk, total aversion risk, reward-aversion trade-off, trade-off range, reward-aversion consistency, and consistency range. Loss aversion, risk aversion, loss resilience, ante, and insurance are derived from the logarithmic or power-law fit of mean picture ratings ( K ) versus entropy of ratings ( H ); this is referred to as the value function ( Figure 1 B). Peak positive risk, peak negative risk, reward tipping point, aversion tipping point, total reward risk, and total aversion risk are derived from the quadratic fit of K versus the SD of picture ratings ( σ ); this is referred to as the limit function ( Figure 1 C). Risk aversion trade-off, trade-off range, risk aversion consistency, and consistency range are derived from the radial fit of the pattern of avoidance judgments ( H − ) versus the pattern of approach judgments ( H + ); this is referred to as the trade-off function ( Figure 1 D). Value (Figure S2A in Multimedia Appendix 1 ), limit (Figure S2B in Multimedia Appendix 1 ), and trade-off (Figure S2C in Multimedia Appendix 1 ) functions were plotted for 500 randomly sampled participants, and nonlinear curve fits were assessed for goodness of fit, yielding R 2 , adjusted R 2 , and the associated F statistic for all participants (Figure S2D in Multimedia Appendix 1 ). Only the logarithmic and quadratic fits are listed in Table S3 in Multimedia Appendix 1 . Each feature describes a quantitative component of a participant’s reward and aversion judgment (refer to Table 1 for abbreviated descriptions and Multimedia Appendix 1 for complete descriptions). Collectively, the 15 RPT features will be henceforth referred to as “judgment variables.” The summary statistics for these variables can be found in Table S3 in Multimedia Appendix 1 .

Statistical and Machine Learning Analyses

Wilcoxon rank sum tests, chi-square tests, and Gini importance plotting were performed in Stata (version 17; StataCorp) [ 72 ]. Machine learning algorithms were run in Python (version 3.9; Python Software Foundation) [ 73 ], where the scikit-learn (version 1.2.2) [ 74 ] and imbalanced-learn (version 0.10.1) [ 75 ] libraries were used. Post hoc mediation and moderation analyses were performed in R (version 4.2.0; R Foundation for Statistical Computing) [ 76 ].

Demographic and Judgment Variable Differences by Vaccination Uptake

Each of the 7 demographic variables (age, income, marital status, employment status, ethnicity, educational level, and sex) was assessed for differences using yes or no responses to receiving the full COVID-19 vaccination (2525/3476, 72.64% yes responses and 951/3476, 27.36% no responses), henceforth referred to as vaccine uptake . Ordinal (income and educational level) and continuous (age) demographic variables were analyzed using the Wilcoxon rank sum test ( α =.05). Expected and actual rank sums were reported using Wilcoxon rank sum tests. Nominal variables were analyzed using the chi-square test ( α =.05). For significant chi-square results, demographic response percentages were computed to compare the fully vaccinated and not fully vaccinated groups.

Each of the 15 judgment variables was assessed for differences across yes or no responses to vaccine uptake using the Wilcoxon rank sum test ( α =.05). The expected and actual rank sums were reported. Significant results ( α <.05) were corrected for multiple comparisons using the Benjamini-Hochberg correction, and Q values of <0.05 ( Q Hoch ) were reported.

Prediction Analyses

Logistic regression, random forest, and BRF were used to predict vaccine uptake using judgment, demographic, and COVID-19 precaution variables. Gini plots were produced for random forest and BRF to determine the importance of the judgment variables in predicting COVID-19 vaccination. The BRF algorithm balances the samples by randomly downsampling the majority class at each bootstrapped iteration to match the number of samples in the minority class. To provide greater certainty about the results, random forest and logistic regression were performed to compare with BRF results.

Two sets of BRF, random forest, and logistic regression analyses were run: (1) with the 7 demographic variables and 15 judgment variables included as predictors and (2) with the 7 demographic variables, 15 judgment variables, and 4 COVID-19 precaution behaviors included as predictors. COVID-19 precaution behaviors included yes or no responses to wearing a mask, social distancing, washing hands, and avoiding large gatherings (refer to Table S1 in Multimedia Appendix 1 for more details). The sample sizes for yes or no responses to the COVID-19 precaution behavior questions are provided in Table S2 in Multimedia Appendix 1 . For all 3 models, 10-fold cross-validation was repeated 100 times to obtain performance metrics, where data were split for training (90%) and testing (10%) for each of the 10 iterations in cross-validation. The averages of the performance metrics were reported across 100 repeats of 10-fold cross-validation for the test sets. The reported metrics included accuracy, recall, specificity, negative predictive value (NPV), precision, and area under the receiver operating characteristic curve (AUROC). For BRF, the Python toolbox imbalanced-learn was used to build the classifier, where the training set for each iteration of cross-validation was downsampled but the testing set was unchanged (ie, imbalanced). That is, downsampling only occurred with the bootstrapped samples for training the model, and balancing was not performed on the testing set. The default number of estimators was 100, and the default number of tree splits was 10; the splits were created using the Gini criterion. In separate analyses, estimators were increased to 300, and splits were increased to 15 to test model performance. Using the scikit-learn library, the same procedures used for BRF were followed for random forest without downsampling. Logistic regression without downsampling was implemented with a maximum of 100 iterations and optimization using a limited-memory Broyden-Fletcher-Goldfarb-Shanno solver. For logistic regression, model coefficients with respective SEs, z statistics, P values, and 95% CIs were reported.

Relative feature importance based on the Gini criterion (henceforth referred to as Gini importance ) was determined from BRF and random forest using the .feature_importances_ attribute from scikit-learn, and results were reported as the mean decrease in the Gini score and plotted in Stata. To test model performance using only the top predictors, two additional sets of BRF analyses were run: (1) with the top 3 features as predictors and (2) with the top 3 features and 15 judgment variables as predictors.

Post Hoc Mediation and Moderation

Given the importance of both judgment variables and demographic variables (refer to the Results section), we evaluated post hoc how age, income, and educational level (ie, the top 3 predictors) might statistically influence the relationship between the 15 judgment variables and COVID-19 vaccine uptake . To identify statistical mechanisms influencing our prediction results, we used mediation and moderation, which can (1) determine the directionality between variables and (2) assess variable influence in statistical relationships. Mediation is used to determine whether one variable, the mediator, statistically improves the relationship between 2 other variables (independent variables [IVs] and dependent variables [DVs]) [ 77 - 80 ]. When mediating variables improve a relationship, the mediator is said to sit in the statistical pathway between the IVs and DVs [ 77 , 80 , 81 ]. Moderation is used to test whether the interaction between an IV and a moderating variable predicts a DV [ 81 , 82 ].

For mediation, primary and secondary mediations were performed. Primary mediations included each of the 15 judgment behaviors as the IV, each of the 3 demographic variables (age, income, and educational level) as the mediator, and vaccine uptake as the DV. Secondary mediations held the 15 judgment behaviors as the mediator, the 3 demographic variables as the IV, and vaccine uptake as the DV. For moderation, the moderating variable was each of the 3 demographic variables (age, income, and educational level), the IV was each of the 15 judgment behaviors, and the DV was vaccine uptake . The mathematical procedures for mediation and moderation can be found in Multimedia Appendix 1 .

Demographic Assessment

Of the 400,000 persons queried by Gold Research, Inc, 48,000 (12%) completed the survey, and 3476 (0.87%) survived all quality assurance procedures. Participants were predominately female, married, and White individuals; employed full time with some college education; and middle-aged (mean age 51.40, SD 14.92 years; Table 2 ). Of the 3476 participants, 2525 (72.64%) reported receiving a full dose of a COVID-19 vaccine, and 951 (27.36%) reported not receiving a full dose. Participants who indicated full vaccination were predominately female, married, White individuals, and retired; had some college education; and were older on average (mean age 54.19, SD 14.13 years) when compared to the total cohort. Participants who indicated that they did not receive the full vaccine were also predominately female, married, and White individuals. In contrast to those who received the full vaccination, those not fully vaccinated were predominately employed full time, high school graduates, and of average age (mean age 43.98, SD 14.45 years; median age 45, IQR 32-56 years) when compared to the total cohort. Table 2 summarizes the demographic group sample size percentages for the total cohort, those fully vaccinated, and those not fully vaccinated.

When comparing percentages between vaccination groups, a higher percentage of male individuals were fully vaccinated, and a higher percentage of female individuals were not fully vaccinated ( Table 2 ). In addition, a higher percentage of married, White and Asian or Pacific Islander, and retired individuals indicated receiving the full vaccine when compared to the percentages of those who did not receive the vaccine ( Table 2 ). Conversely, a higher percentage of single, African American, and unemployed individuals indicated not receiving the full vaccine ( Table 2 ).

Analysis of Machine Learning Features

Demographic variable differences by vaccine uptake.

Age, income level, and educational level significantly differed between those who did and did not receive the vaccine (Wilcoxon rank sum test α <.05; Table 3 ). Those who indicated full vaccination were, on average, older (median age 59 y), had a higher annual household income (median reported income level US $50,000-$75,000), and had higher levels of education (the median reported educational level was a bachelor’s degree).

Chi-square tests revealed that marital status, employment status, sex, and ethnicity also varied by full vaccine uptake (chi-square α <.05; Table 3 ).

a N/A: not applicable.

Judgment Variable Differences by Vaccine Uptake

In total, 10 of the 15 judgment variables showed nominal rank differences ( α <.05), and 9 showed significant rank differences after correction for multiple comparisons ( Q Hoch <0.05) between those who indicated full vaccination and those who indicated that they did not receive the full vaccination ( Table 4 ). The 10 features included loss aversion, risk aversion, loss resilience, ante, insurance, peak positive risk, peak negative risk, total reward risk, total aversion risk, and trade-off range. Those who indicated full vaccination exhibited lower loss aversion, ante, peak positive risk, peak negative risk, total reward risk, and total aversion risk as well as higher risk aversion, loss resilience, insurance, and trade-off range when compared to the expected rank sum. Those who did not receive the full vaccination exhibited lower risk aversion, loss resilience, insurance, and trade-off range and higher loss aversion, ante, peak positive risk, peak negative risk, total reward risk, and total aversion risk when compared to the expected rank sum.

Machine Learning Results: Predicting Vaccination Uptake

Prediction results.

With the inclusion of demographic and judgment variables, the BRF classifier with the highest accuracy (68.9%) and precision (86.7%) in predicting vaccine uptake resulted when the number of estimators was set to 300 and the number of splits was set to 10 ( Table 5 ). With the addition of 4 COVID-19 precaution behaviors, the BRF classifier with the highest accuracy (70.8%) and precision (87.8%) to predict vaccine uptake occurred when the number of estimators was set to 300 and the number of splits was set to 10. It is notable that specificity was consistently >72%, precision was >86%, and the AUROC was >75% but the NPV was consistently <50%. For random forest and logistic regression, recall and accuracy values were higher than those for BRF, but specificity was always <39%, indicating a lower performance in predicting those who did not receive the vaccine. Precision was also lower, yet the AUROC was consistent with that of the BRF results.

a A total of 15 judgment variables ( Table 4 ), 7 demographic variables ( Table 3 ), and 4 COVID-19 precaution behavior (covid_beh) variables (Table S1 in Multimedia Appendix 1 ) were included in balanced random forest, random forest, and logistic regression models to predict COVID-19 vaccine uptake . We used 10-fold cross-validation, where the data were split 90-10 for each of the 10 iterations.

b NPV: negative predictive value.

c AUROC: area under the receiver operating characteristic curve.

d BRF: balanced random forest.

e N/A: not applicable.

Feature Importance for BRF and Random Forest

Regarding BRF, Gini importance was highest for age, educational level, and income in both BRF classifiers (both without [ Figures 3 A and 3B] and with [ Figures 3 C and 3D] inclusion of the COVID-19 precaution behaviors; refer to the clusters outlined in red in Figures 3 B and 3D). For both BRF classifiers, the top 3 predictors (age, income, and educational level) had a combined effect of 23.4% on the Gini importance for prediction. Following these predictors, the 15 judgment variables had similar importance scores for both BRF classifiers (range 0.037-0.049; refer to the clusters outlined in black in Figures 3 B and 3D). These 15 predictors had a combined effect of 62.9% to 68.7% on the Gini importance for prediction, indicating that judgment variables were collectively the most important for prediction outcomes. The least important features for predicting vaccination status were demographic variables regarding employment status, marital status, ethnicity, sex, and the 4 COVID-19 precaution behaviors. These predictors only contributed 7.3% to the Gini importance for prediction. As a follow-up analysis, BRF analyses were run using the top 3 features from both the Gini importance plots (age, educational level, and income; Table S4 in Multimedia Appendix 1 ) and the top 3 features plus 15 judgment variables (Table S5 in Multimedia Appendix 1 ). The results did not outperform those presented in Table 5 .

For random forest, the Gini importance was highest for age and educational level ( Figure 4 ). These top 2 predictors had a combined effect of 16.5% to 16.8% for the 2 models ( Figures 4 A and 4C). Following these predictors, the 15 judgment variables and the income variable had similar Gini importance, with a combined effect of 69.4% to 75.5% for Gini importance. The least important predictors mirrored those of the BRF results.

Logistic Regression Model Statistics

Both model 1 (demographic and judgment variables) and model 2 (demographic, judgment, and COVID-19 precaution behavior variables) were significant ( P <.001). The model statistics are provided in Tables 6 (model 1) and 7 (model 2). In model 1, age, income, marital status, employment status, sex, educational level, ante, aversion tipping point, reward-aversion consistency, and consistency range were significant ( α <.05). In model 2, age, income, marital status, employment status, sex, educational level, risk aversion, ante, peak negative risk, mask wearing, and not gathering in large groups were significant ( α <.05).

a Overall model: P <.001; pseudo- R 2 =0.149; log-likelihood=−1736.8; log-likelihood null=−2039.7.

a Overall model: P <.001; pseudo- R 2 =0.206; log-likelihood=−1620.0; log-likelihood null=−2039.7.

Because judgment variables and demographic variables (age, income, and educational level) were important predictors, we evaluated post hoc whether demographics statistically mediated or moderated the relationship between each of the 15 judgment variables and binary responses to COVID-19 vaccination.

For primary mediations, age significantly mediated the statistical relationship between 11 judgment variables and vaccine uptake ( α <.05; Table 8 ), income mediated 8 relationships α < <.05; Table 8 ), and educational level mediated 9 relationships ( α <.05; Table 8 ). In total, 7 judgment variables overlapped across the 3 models: loss resilience, ante, insurance, peak positive risk, peak negative risk, risk aversion trade-off, and consistency range. Of these, 5 significantly differed between vaccine uptake (those fully vaccinated and those not): loss resilience, ante, insurance, peak positive risk, and peak negative risk ( Table 3 ). Thus, 2 judgment features did not differ by vaccine uptake but were connected with uptake by significant mediation.

For the secondary mediation analyses, 5 judgment variables mediated the statistical relationship between age and vaccine uptake ; these variables overlapped with the 11 findings of the primary mediation analyses. Furthermore, 4 judgment variables mediated the statistical relationship between income and vaccine uptake ; these variables overlapped with the 8 findings of the primary mediation analyses. Finally, 4 judgment variables mediated the statistical relationship between educational level and vaccine uptake ; these variables overlapped with the 9 findings of the primary mediation analyses. In all secondary analyses, approximately half of the judgment variables were involved in mediation as compared to the doubling of judgment variable numbers observed in the primary mediation analyses. In the secondary mediation analyses, the same 4 judgment variables were found in both primary and secondary mediation results, indicating a mixed mediation framework.

From the moderation analyses, only 2 interactions out of a potential 45 were observed. Age interacted with risk aversion trade-off, and income interacted with loss resilience to statistically predict vaccine uptake ( α <.05; Table 8 ). The 2 moderation results overlapped with the mediation results, indicating mixed mediation-moderation relationships [ 78 , 80 , 81 ].

Principal Findings

Relatively few studies have sought to predict COVID-19 vaccine uptake using machine learning approaches [ 8 , 59 ]. Given that a small set of studies has assessed the psychological basis that may underlie vaccine uptake and choices [ 6 , 52 , 53 , 56 , 58 , 59 , 83 ], but none have used computational cognition variables based on reward and aversion judgment to predict vaccine uptake , we sought to assess whether variables quantifying human judgment predicted vaccine uptake . This study found that 7 demographic and 15 judgment variables predicted vaccine uptake with balanced and moderate recall and specificity, moderate accuracy, high AUROC, and high precision using a BRF framework. Other machine learning approaches (random forest and logistic regression) produced higher accuracies but lower specificities, indicating a lower prediction of those who did not receive the vaccine. The BRF also had challenges predicting the negative class, as demonstrated by the relatively low NPV despite having higher specificity than random forest and logistic regression. Feature importance analyses from both BRF and random forest showed that the judgment variables collectively dominated the Gini importance scores. Furthermore, demographic variables acted as statistical mediators in the relationship between judgment variables and vaccine uptake . These mediation findings support the interpretation of the machine learning results that demographic factors, together with judgment variables, predict COVID-19 vaccine uptake .

Interpretation of Judgment Differences Between Vaccinated and Nonvaccinated Individuals

Those who were fully vaccinated had lower values for loss aversion, ante, peak positive risk, peak negative risk, total reward risk, and total aversion risk, along with higher values for risk aversion, loss resilience, insurance, and trade-off range (refer to Table 1 for variable descriptions). Lower loss aversion corresponds to less overweighting of bad outcomes relative to good ones [ 84 ] and a potential willingness to obtain a vaccine with uncertain outcomes. A lower ante suggests that individuals are less willing to engage in risky behaviors surrounding potential infection, which is also consistent with the 4 other judgment variables that define relationships between risk and value (peak positive risk, peak negative risk, total reward risk, and total aversion risk). In participants who indicated full vaccination, lower peak positive risk and peak negative risk were related to individuals having a lower risk that they must overcome to make a choice to either approach or avoid, as per the decision utility equation by Markowitz [ 39 , 71 ]. The lower total reward risk and total aversion risk indicate that the interactions between reward, aversion, and the risks associated with them did not scale significantly; namely, higher reward was not associated with higher risk, and higher negative outcomes were not associated with the uncertainty of them. For these participants, the ability of the vaccine to increase the probability of health and reduce the probability of harm from illness did not have to overcome high obstacles in their vaccine choice. Higher risk aversion in vaccinated participants suggests that these participants viewed contracting COVID-19 as a larger risk and, therefore, were more likely to receive the full dose. These findings are consistent with those of a study by Lepinteur et al [ 58 ], who found that risk-averse individuals were more likely to accept the COVID-19 vaccination, indicating that the perceived risk of contracting COVID-19 was greater than any risk from the vaccine. Hudson and Montelpare [ 54 ] also found that risk aversion may promote vaccine adherence when people perceive contracting a disease as more dangerous or likely. Higher loss resilience in the vaccinated group was also consistent with the perspective that vaccination would improve their resilience and act as a form of insurance against negative consequences. The higher trade-off range suggests that vaccinated individuals have a broader portfolio of preferences and are more adaptive to bad things occurring, whereas a lower trade-off indicates a restriction in preferences and less adaptability in those who did not receive the vaccine.

Comparison of Prediction Algorithms

When testing these judgment variables (with demographic and COVID-19 precaution behavior variables) in a BRF framework to predict vaccine uptake , we observed a high AUROC of 0.79, where an AUROC of 0.8 is often the threshold for excellent model performance in machine learning [ 85 , 86 ]. The similarity of our reported recall and specificity values with the BRF suggests a balance between predicting true positives and true negatives. The high precision indicates a high certainty in predicting those who were fully vaccinated. The BRF model was successful in identifying those who received the full vaccine (positive cases; indicated by high precision and moderate recall) and those who did not (negative cases; indicated by the specificity). However, NPV was low, indicating a higher rate of false prediction of those who did not receive a full dose counterbalanced by a higher specificity that reflects a higher rate of predicting true negatives. These observations are reflected in the moderate accuracy, which measures the number of correct predictions. A comparison of random forest, logistic regression, and BRF revealed that random forest and logistic regression models produced less balance between recall (high) and specificity (low), which could be interpreted as a bias toward predicting the majority class (ie, those who received the vaccine). That being said, the NPV for BRF was lower than that for random forest and logistic regression, where a low NPV indicates a low probability that those predicted to have not received the vaccine truly did not receive the vaccine when taking both classes into account. Together, the results from all 3 machine learning approaches reveal challenges in predicting the negative class (ie, those who did not receive the vaccine). Overall, the 3 models achieved high accuracy, recall, precision, and AUROC. BRF produced a greater balance between recall and specificity, and the outcome of the worst-performing metric (ie, NPV) was still higher than the specificities for the random forest and logistic regression models.

Feature Importance

Of the 3 prediction algorithms, random forest and BRF had very similar Gini importance results, whereas logistic regression elevated most demographic variables and a minority of judgment variables. This observation could be due to the large variance in each of the judgment variables, which could present challenges for achieving a good fit with logistic regression. In contrast, the demographic and COVID-19 precaution variables had low variance and could be more easily fit in a linear model, hence their significance in the logistic regression results. In comparison to logistic regression, decision trees (eg, BRF and random forest) use variable variance as additional information to optimize classification, potentially leading to a higher importance of judgment variables over most demographic and all COVID-19 precaution variables.

Focusing on the model with balanced recall and specificity (ie, the BRF classifiers [with and without COVID-19 precaution behaviors]), the top predictors were 3 demographic variables (age, income, and educational level), with distributions that varied by vaccine uptake in manners consistent with those of other reports. Namely, older individuals, those identifying as male and White individuals, and those who indicated a higher income and educational level corresponded to those who were or intended to be vaccinated [ 2 , 5 , 87 ]. Despite their saliency, these 3 variables together only contributed 23% to the prediction, corresponding to approximately one-third of the contribution from the 15 judgment variables (63%-69%). The individual Gini importance scores for the 15 judgment variables only ranged from 0.039 to 0.049 but were the dominant set of features behind the moderate accuracy, high precision, and high AUROC. The 18% difference between the accuracy and precision measures suggests that variables other than those used in this study may improve prediction, including contextual variables that may influence vaccine choices. Variables may include political affiliation [ 7 ], longitude and latitude [ 8 ], access to the internet [ 8 ], health literacy [ 54 ], and presence of underlying conditions [ 9 ]. Future work should seek to include these types of variables.

In the second BRF classifier, the 4 COVID-19 precaution behaviors only contributed 6.6% to the prediction. This low contribution could be due to these variables being binary, unlike the other demographic variables, which included a range of categories. In addition, COVID-19 precaution behaviors are specific to the context of the COVID-19 pandemic and do not promote interpretation beyond their specific context. The 15 judgment variables represent a contrast to this as they are empirically computed from a set of functions across many picture categories. An individual with higher risk aversion will generally tolerate higher amounts of uncertainty regarding a potential upside or gain as opposed to settling for what they have. This does not depend on what stimulus category they observe or the stimulus-response condition. Instead, it is a general feature of the bounds to their judgment and is part of what behavioral economists such as Kahneman consider as bounds to human rationality [ 84 ].

Mechanistic Relationships Between Judgment and Demographic Variables

The Gini score plots were clear sigmoid-like graphs ( Figure 3 ), with only 3 of the 7 demographic variables ranking above the judgment variables. This observation was consistent in both BRF classifiers (with and without COVID-19 precaution behaviors), raising the possibility of a statistically mechanistic relationship among the top 3 demographic variables, the 15 judgment variables, and vaccine uptake . Indeed, we observed 28 primary mediation effects and 13 secondary mediation effects in contrast to 2 moderation relationships, which also happened to overlap with mediation findings, suggesting mixed mediation-moderation relationships [ 81 , 88 ]. The observation that most judgment variables were significant in mediation relationships but not in moderation relationships argues that prediction depended on the directional relationship between judgment and demographic variables to predict vaccine uptake . Furthermore, there were more significant primary mediations (when judgment variables were the IVs) compared to secondary mediations, suggesting the importance of judgment variables as IVs and demographic variables as mediators. Mathematically, judgment variables (IVs) influenced vaccine uptake (DV), and this relationship was stronger when demographic variables were added to the equation. The 13 secondary mediations all overlapped with the 28 primary mediations, where demographic variables were IVs and judgment variables were mediators, suggesting that demographic variables influenced vaccine uptake (DV) and that this relationship became stronger with the addition of judgment variables. This overlap of primary and secondary mediations for 4 of the judgment variables suggests that both judgment and demographic variables influenced the choice of being vaccinated within a mixed mediation framework because adding either one of them to the mediation model regressions made the relationships stronger [ 49 ]. The lack of moderation results and a considerable number of overlapping primary and secondary mediation results imply that the relationship between judgment variables and vaccine uptake did not depend purely on their interaction with age, income, or educational level (ie, moderation) but, instead, depended on the direct effects of these 3 demographic variables to strengthen the relationship between judgment variables and vaccine uptake . This type of analysis of statistical mechanisms is helpful for understanding contextual effects on our biases and might be important for considering how best to target or message those with higher loss aversion, ante, peak positive risk, peak negative risk, total reward risk, and total aversion risk (ie, in those who were not fully vaccinated).

Model Utility

The developed model is automatable and may have applications in public health. The picture-rating task can be deployed on any smart device or computer, making it accessible to much of the US population or regional populations. The ratings from this task can be automatically processed, and the results can be stored in local or national databases. This method of data collection is novel in that persons cannot bias their responses as the rating task has no perceivable relation to vaccination choices. Government and public health bodies can access these data to determine predicted vaccine uptake rates locally or nationally, which can be used to (1) prepare vaccine rollouts and supply chain demand, (2) prepare health care institutions in areas that may experience low vaccine adherence and potentially higher infection rates, and (3) determine which areas may need more targeted messaging to appeal to specific judgment profiles. For use case 3, messaging about infection risks or precaution behaviors could be framed to address those with lower risk aversion, who, in this study, tended to forgo vaccination. Given that such individualized data would not be available a priori, it would be more plausible to collect data from similarly sized cohorts in geographic regions of concern to obtain regional judgment behavior profiles and, thus, target use cases 1 to 3. Further development of this model with different population samples might also improve our understanding of how certain judgment variables may be targeted with different types of messaging, offering a means to potentially improve vaccine uptake . This model might also be applied to other mandated or recommended vaccines such as those for influenza or human papillomavirus, ultimately improving preparation and messaging efforts. However, future work would be needed to model these varying vaccine choices.

Given the use of demographic variables in the proposed model, specific demographic populations could be assessed or considered for messaging. If particular demographic groups are predicted to have a low vaccine uptake rate, messaging can be targeted to those specific groups. For example, we observed that a higher percentage of female individuals were not fully vaccinated when compared to male individuals. This could be related to concerns about the COVID-19 vaccine affecting fertility or pregnancy. To improve uptake in this population, scientifically backed messaging could be used to confirm the safety of the vaccine in this context. Lower rates of vaccination have been reported in Black communities, which was also observed in this study. Researchers have identified targetable issues related to this observation, which include engagement of Black faith leaders and accessibility of vaccination clinics in Black communities, to name a few [ 89 ].

In summary, this model could be used to predict vaccine uptake at the local and national levels and further assess the demographic and judgment features that may underlie these choices.

Limitations

This study has a number of limitations that should be considered. First, there are the inherent limitations of using an internet survey—namely, the uncontrolled environment in which participants provide responses. Gold Research, Inc, and the research team applied stringent exclusion criteria, including the evaluation of the judgment graphs given that random responses produce graphs with extremely low R 2 fits (eg, <0.1). This was not the case in our cohort of 3476 participants, but this cannot perfectly exclude random or erroneous responses to other questionnaire components. Second, participants with mental health conditions were oversampled to meet the criteria for other survey components not discussed in this paper. This oversampling could potentially bias the results, and future work should use a general population sample to verify these findings. Third, demographic variability and the resulting confounds are inherent in population surveys, and other demographic factors not collected in this study may be important for prediction (eg, religion and family size). Future work might consider collecting a broader array of demographic factors to investigate and include in predictive modeling. Fourth, we used a limited set of 7 demographic variables and 15 judgment variables; however, a larger set of judgment variables is potentially computable and could be considered for future studies. There is also little information on how post–COVID-19 effects, including socioeconomic effects, affect COVID-19 vaccination choices.

Conclusions

To our knowledge, there has been minimal research on how biases in human judgment might contribute to the psychology underlying individual vaccination preferences and what differentiates individuals who were fully vaccinated against COVID-19 from those who were not. This population study of several thousand participants demonstrated that a small set of demographic variables and 15 judgment variables predicted vaccine uptake with moderate to high accuracy and high precision and AUROC, although a large range of specificities was achieved depending on the classification method used. In an age of big data machine learning approaches, this study provides an option for using fewer but more interpretable variables. Age, income, and educational level were independently the most important predictors of vaccine uptake , but judgment variables collectively dominated the importance rankings and contributed almost two-thirds to the prediction of COVID-19 vaccination for the BRF and random forest models. Age, income, and educational level significantly mediated the statistical relationship between judgment variables and vaccine uptake , indicating a statistically mechanistic relationship grounding the prediction results. These findings support the hypothesis that small sets of judgment variables might provide a target for vaccine education and messaging to improve uptake. Such education and messaging might also need to consider contextual variables (ie, age, income, and educational level) that mediate the effect of judgment variables on vaccine uptake . Judgment and demographic variables can be readily collected using any digital device, including smartphones, which are accessible worldwide. Further development and use of this model could (1) improve vaccine uptake , (2) better prepare vaccine rollouts and health care institutions, (3) improve messaging efforts, and (4) have applications for other mandated or government-recommended vaccines.

Acknowledgments

The authors thank Carol Ross, Angela Braggs-Brown, Tom Talavage, Eric Nauman, and Marc Cahay at the University of Cincinnati (UC) College of Engineering and Applied Sciences, who significantly impacted the transfer of research funding to UC. Funding for this work was provided in part to HCB by the Office of Naval Research (awards N00014-21-1-2216 and N00014-23-1-2396) and to HCB from a Jim Goetz donation to the UC College of Engineering and Applied Sciences. Finally, the authors thank the anonymous reviewers for their constructive input, which substantially improved the manuscript. The opinions expressed in this paper are those of the authors and are not necessarily representative of those of their respective institutions.

Data Availability

The data set and corresponding key used in this study are available in Multimedia Appendix 2 .

Conflicts of Interest

A provisional patent has been submitted by the following authors (NLV, SB, HCB, SL, LS, and AKK): “Methods of predicting vaccine uptake,” provisional application # 63/449,460.

Supplementary material.

• Ezati Rad R, Kahnouji K, Mohseni S, Shahabi N, Noruziyan F, Farshidi H, et al. Predicting the COVID-19 vaccine receive intention based on the theory of reasoned action in the south of Iran. BMC Public Health. Feb 04, 2022;22(1):229. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Mewhirter J, Sagir M, Sanders R. Towards a predictive model of COVID-19 vaccine hesitancy among American adults. Vaccine. Mar 15, 2022;40(12):1783-1789. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Romate J, Rajkumar E, Greeshma R. Using the integrative model of behavioural prediction to understand COVID-19 vaccine hesitancy behaviour. Sci Rep. Jun 04, 2022;12(1):9344. [ CrossRef ] [ Medline ]
• Kalam MA, Davis TPJ, Shano S, Uddin MN, Islam MA, Kanwagi R, et al. Exploring the behavioral determinants of COVID-19 vaccine acceptance among an urban population in Bangladesh: implications for behavior change interventions. PLoS One. 2021;16(8):e0256496. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Koesnoe S, Siddiq TH, Pelupessy DC, Yunihastuti E, Awanis GS, Widhani A, et al. Using integrative behavior model to predict COVID-19 vaccination intention among health care workers in Indonesia: a nationwide survey. Vaccines (Basel). May 04, 2022;10(5):719. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Hudson A, Hall PA, Hitchman SC, Meng G, Fong GT. Cognitive predictors of COVID-19 mitigation behaviors in vaccinated and unvaccinated general population members. Vaccine. Jun 19, 2023;41(27):4019-4026. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Dhanani LY, Franz B. A meta-analysis of COVID-19 vaccine attitudes and demographic characteristics in the United States. Public Health. Jun 2022;207:31-38. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Cheong Q, Au-Yeung M, Quon S, Concepcion K, Kong JD. Predictive modeling of vaccination uptake in US counties: a machine learning-based approach. J Med Internet Res. Nov 25, 2021;23(11):e33231. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Bulusu A, Segarra C, Khayat L. Analysis of COVID-19 vaccine uptake among people with underlying chronic conditions in 2022: a cross-sectional study. SSM Popul Health. Jun 2023;22:101422. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Painter EM, Ussery EN, Patel A, Hughes MM, Zell ER, Moulia DL, et al. Demographic characteristics of persons vaccinated during the first month of the COVID-19 vaccination program - United States, December 14, 2020-January 14, 2021. MMWR Morb Mortal Wkly Rep. Feb 05, 2021;70(5):174-177. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Azcona EA, Kim BW, Vike NL, Bari S, Lalvani S, Stefanopoulos L, et al. Discrete, recurrent, and scalable patterns in human judgement underlie affective picture ratings. arXiv. Preprint posted online March 12, 2022. 2022.:2203.06448. [ FREE Full text ] [ CrossRef ]
• Breiter HC, Block M, Blood AJ, Calder B, Chamberlain L, Lee N, et al. Redefining neuromarketing as an integrated science of influence. Front Hum Neurosci. Feb 12, 2014;8:1073. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Schneirla TC. An evolutionary and developmental theory of biphasic processes underlying approach and withdrawal. In: Jones MR, editor. Nebraska Symposium on Motivation. Lincoln, Nebraska. University of Nebraska Press; 1959;1-42.
• Schneirla TC. Aspects of stimulation and organization in approach/withdrawal processes underlying vertebrate behavioral development. In: Advances in the Study of Behavior. Cambridge, MA. Academic Press; 1965;1-74.
• Lewin K. Psycho-sociological problems of a minority group. J Personality. Mar 1935;3(3):175-187. [ CrossRef ]
• Herrnstein RJ. Secondary reinforcement and rate of primary reinforcement. J Exp Anal Behav. Jan 1964;7(1):27-36. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Baum WM. On two types of deviation from the matching law: bias and undermatching. J Exp Anal Behav. Jul 1974;22(1):231-242. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Kim BW, Kennedy DN, Lehár J, Lee MJ, Blood AJ, Lee S, et al. Recurrent, robust and scalable patterns underlie human approach and avoidance. PLoS One. May 26, 2010;5(5):e10613. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Berridge KC, Robinson TE. The mind of an addicted brain: neural sensitization of wanting versus liking. Curr Dir Psychol Sci. 1995;4(3):71-76. [ FREE Full text ] [ CrossRef ]
• Montague PR. Free will. Curr Biol. Jul 22, 2008;18(14):R584-R585. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Dai X, Brendl CM, Ariely D. Wanting, liking, and preference construction. Emotion. Jun 2010;10(3):324-334. [ CrossRef ] [ Medline ]
• Mas-Colell A, Whinston MD, Green JR. Microeconomic Theory. Oxford, UK. Oxford University Press; 1995.
• Marshall A. Principles of Economics. Buffalo, NY. Prometheus Books; 1997.
• Aharon I, Etcoff N, Ariely D, Chabris CF, O'Connor E, Breiter HC. Beautiful faces have variable reward value: fMRI and behavioral evidence. Neuron. Nov 08, 2001;32(3):537-551. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Viswanathan V, Lee S, Gilman JM, Kim BW, Lee N, Chamberlain L, et al. Age-related striatal BOLD changes without changes in behavioral loss aversion. Front Hum Neurosci. Apr 30, 2015;9:176. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Perlis RH, Holt DJ, Smoller JW, Blood AJ, Lee S, Kim BW, et al. Association of a polymorphism near CREB1 with differential aversion processing in the insula of healthy participants. Arch Gen Psychiatry. Aug 2008;65(8):882-892. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Gasic GP, Smoller JW, Perlis RH, Sun M, Lee S, Kim BW, et al. BDNF, relative preference, and reward circuitry responses to emotional communication. Am J Med Genet B Neuropsychiatr Genet. Sep 05, 2009;150B(6):762-781. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Makris N, Oscar-Berman M, Jaffin SK, Hodge SM, Kennedy DN, Caviness VS, et al. Decreased volume of the brain reward system in alcoholism. Biol Psychiatry. Aug 01, 2008;64(3):192-202. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Elman I, Ariely D, Mazar N, Aharon I, Lasko NB, Macklin ML, et al. Probing reward function in post-traumatic stress disorder with beautiful facial images. Psychiatry Res. Jun 30, 2005;135(3):179-183. [ CrossRef ] [ Medline ]
• Strauss MM, Makris N, Aharon I, Vangel MG, Goodman J, Kennedy DN, et al. fMRI of sensitization to angry faces. Neuroimage. Jun 18, 2005;26(2):389-413. [ CrossRef ] [ Medline ]
• Levy B, Ariely D, Mazar N, Chi W, Lukas S, Elman I. Gender differences in the motivational processing of facial beauty. Learn Motiv. May 2008;39(2):10.1016/j.lmot.2007.09.002. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Yamamoto R, Ariely D, Chi W, Langleben DD, Elman I. Gender differences in the motivational processing of babies are determined by their facial attractiveness. PLoS One. Jun 24, 2009;4(6):e6042. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Viswanathan V, Sheppard JP, Kim BW, Plantz CL, Ying H, Lee MJ, et al. A quantitative relationship between signal detection in attention and approach/avoidance behavior. Front Psychol. Feb 21, 2017;8:122. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Stefanopoulos L, Lalvani S, Kim BW, Vike NL, Bari S, Emanuel A, et al. Predicting depression history from a short reward/aversion task with behavioral economic features. In: Proceedings of the International Conference on Biomedical and Health Informatics 2022. 2022. Presented at: ICBHI 2022; November 24-26, 2022; Concepcion, Chile.
• Shannon CE, Weaver W. The Mathematical Theory of Communication. Urbana, IL. The University of Illinois Press; 1949.
• Livengood SL, Sheppard JP, Kim BW, Malthouse EC, Bourne JE, Barlow AE, et al. Keypress-based musical preference is both individual and lawful. Front Neurosci. May 02, 2017;11:136. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Feynman R, Wilczek F. The Character of Physical Law. New York, NY. Modern Library; 1965.
• Kahneman D, Tversky A. Prospect theory: an analysis of decision under risk. Econometrica. Mar 1979;47(2):263-292. [ CrossRef ]
• Markowitz H. Portfolio selection*. J Finance. Apr 30, 2012;7(1):77-91. [ CrossRef ]
• Nagaya K. Why and under what conditions does loss aversion emerge? Jpn Psychol Res. Oct 15, 2021;65(4):379-398. [ CrossRef ]
• Tversky A, Kahneman D. Judgment under uncertainty: heuristics and biases. Science. Sep 27, 1974;185(4157):1124-1131. [ CrossRef ] [ Medline ]
• Macoveanu J, Rowe JB, Hornboll B, Elliott R, Paulson OB, Knudsen GM, et al. Serotonin 2A receptors contribute to the regulation of risk-averse decisions. Neuroimage. Dec 2013;83:35-44. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Macoveanu J, Rowe JB, Hornboll B, Elliott R, Paulson OB, Knudsen GM, et al. Playing it safe but losing anyway--serotonergic signaling of negative outcomes in dorsomedial prefrontal cortex in the context of risk-aversion. Eur Neuropsychopharmacol. Aug 2013;23(8):919-930. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Schultz W. Dopamine signals for reward value and risk: basic and recent data. Behav Brain Funct. Apr 23, 2010;6:24. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Manssuer L, Ding Q, Zhang Y, Gong H, Liu W, Yang R, et al. Risk and aversion coding in human habenula high gamma activity. Brain. Jun 01, 2023;146(6):2642-2653. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Thrailkill EA, DeSarno M, Higgins ST. Intersections between environmental reward availability, loss aversion, and delay discounting as potential risk factors for cigarette smoking and other substance use. Prev Med. Dec 2022;165(Pt B):107270. [ CrossRef ] [ Medline ]
• Vrijen C, Hartman CA, Oldehinkel AJ. Reward-related attentional bias at age 16 predicts onset of depression during 9 years of follow-up. J Am Acad Child Adolesc Psychiatry. Mar 2019;58(3):329-338. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Hansen A, Turpyn CC, Mauro K, Thompson JC, Chaplin TM. Adolescent brain response to reward is associated with a bias toward immediate reward. Dev Neuropsychol. Aug 2019;44(5):417-428. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Morales S, Miller NV, Troller-Renfree SV, White LK, Degnan KA, Henderson HA, et al. Attention bias to reward predicts behavioral problems and moderates early risk to externalizing and attention problems. Dev Psychopathol. May 2020;32(2):397-409. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Wang S, Krajbich I, Adolphs R, Tsuchiya N. The role of risk aversion in non-conscious decision making. Front Psychol. 2012;3:50. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Chen X, Voets S, Jenkinson N, Galea JM. Dopamine-dependent loss aversion during effort-based decision-making. J Neurosci. Jan 15, 2020;40(3):661-670. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Trueblood JS, Sussman AB, O’Leary D. The role of risk preferences in responses to messaging about COVID-19 vaccine take-up. Soc Psychol Personal Sci. Mar 11, 2021;13(1):311-319. [ CrossRef ]
• Wagner CE, Prentice JA, Saad-Roy CM, Yang L, Grenfell BT, Levin SA, et al. Economic and behavioral influencers of vaccination and antimicrobial use. Front Public Health. Dec 21, 2020;8:614113. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Hudson A, Montelpare WJ. Predictors of vaccine hesitancy: implications for COVID-19 public health messaging. Int J Environ Res Public Health. Jul 29, 2021;18(15):8054. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Horne Z, Powell D, Hummel JE, Holyoak KJ. Countering antivaccination attitudes. Proc Natl Acad Sci U S A. Aug 18, 2015;112(33):10321-10324. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Benin AL, Wisler-Scher DJ, Colson E, Shapiro ED, Holmboe ES. Qualitative analysis of mothers' decision-making about vaccines for infants: the importance of trust. Pediatrics. May 2006;117(5):1532-1541. [ CrossRef ] [ Medline ]
• Noyman-Veksler G, Greenberg D, Grotto I, Shahar G. Parents' malevolent personification of mass vaccination solidifies vaccine hesitancy. J Health Psychol. Oct 2021;26(12):2164-2172. [ CrossRef ] [ Medline ]
• Lepinteur A, Borga LG, Clark AE, Vögele C, D'Ambrosio C. Risk aversion and COVID-19 vaccine hesitancy. Health Econ. Aug 2023;32(8):1659-1669. [ CrossRef ] [ Medline ]
• Becchetti L, Candio P, Salustri F. Vaccine uptake and constrained decision making: the case of Covid-19. Soc Sci Med. Nov 2021;289:114410. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Fernández A, García S, Galar M, Prati RC, Krawczyk B, Herrera F. Learning from Imbalanced Data Sets. Cham, Switzerland. Springer International Publishing; 2018.
• Bari S, Vike NL, Stetsiv K, Woodward S, Lalvani S, Stefanopoulos L, et al. The prevalence of psychotic symptoms, violent ideation, and disruptive behavior in a population with SARS-CoV-2 infection: preliminary study. JMIR Form Res. Aug 16, 2022;6(8):e36444. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Woodward SF, Bari S, Vike N, Lalvani S, Stetsiv K, Kim BW, et al. Anxiety, post-COVID-19 syndrome-related depression, and suicidal thoughts and behaviors in COVID-19 survivors: cross-sectional study. JMIR Form Res. Oct 25, 2022;6(10):e36656. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Vike NL, Bari S, Stetsiv K, Woodward S, Lalvani S, Stefanopoulos L, et al. The Relationship Between a History of High-risk and Destructive Behaviors and COVID-19 Infection: Preliminary Study. JMIR Form Res. 2023;7:e40821. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Lee S, Lee MJ, Kim BW, Gilman JM, Kuster JK, Blood AJ, et al. The commonality of loss aversion across procedures and stimuli. PLoS One. Sep 22, 2015;10(9):e0135216. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Tversky A, Kahneman D. Advances in prospect theory: cumulative representation of uncertainty. J Risk Uncertainty. Oct 1992;5(4):297-323. [ CrossRef ]
• Sheppard JP, Livengood SL, Kim BW, Lee MJ, Blood AJ. Connecting prospect and portfolio theories through relative preference behavior. In: Proceedings of the 14th Annual Meeting on Society for NeuroEconomics. 2016. Presented at: SNE '16; August 28-30, 2016;102-103; Berlin, Germany. URL: https://staging.neuroeconomics.org/wp-content/uploads/2016/08/AbstractBookSNE2016.pdf
• Zhang R, Brennan TJ, Lo AW. The origin of risk aversion. Proc Natl Acad Sci U S A. Dec 16, 2014;111(50):17777-17782. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Iacobucci D. Mediation analysis and categorical variables: the final frontier. J Consum Psychol. Apr 12, 2012;22(4):582-594. [ CrossRef ]
• Lang PJ, Bradley MM, Cuthbert MM. Motivated attention: affect, activation and action. In: Lang PJ, Simons RF, Balaban MT, editors. Attention and Orienting: Sensory and Motivational Processes. Hillsdale, NJ. Lawrence Erlbaum Associates; 1997;97-136.
• Lang PJ, Bradley MM, Cuthbert BN. International affective picture system (IAPS): affective ratings of pictures and instruction manual. Technical Report A-8. University of Florida. 2008. URL: https://www.scirp.org/reference/referencespapers?referenceid=755311 [accessed 2021-06-01]
• Markowitz H. The Utility of Wealth. J Political Econ. Apr 1952;60(2):151-158. [ CrossRef ]
• StataCorp. Stata statistical software: release 17. StataCorp LLC. College Station, TX. StataCorp LLC; 2021. URL: https://www.stata.com/company/ [accessed 2024-02-23]
• Van Rossum G, Drake FL. Python 3 Reference Manual. Scotts Valley, CA. CreateSpace Independent Publishing Platform; 2009.
• Pedregosa F, Varoquaux G, Gramfort A, Michel V, Thirion B, Grisel O, et al. Scikit-learn: machine learning in python. J Mach Learn Res. 2011;12(85):2825-2830. [ FREE Full text ]
• Lemaître G, Nogueira F, Aridas CK. Imbalanced-learn: a python toolbox to tackle the curse of imbalanced datasets in machine learning. J Mach Learn Res. 2017;18(17):1-5. [ FREE Full text ]
• R Core Team. R: a language and environment for statistical computing. R Foundation for Statistical Computing. 2019. URL: https://www.r-project.org/ [accessed 2024-02-23]
• David A. Kenny's homepage. David A. Kenny. URL: http://davidakenny.net/cm/mediate.htm [accessed 2024-02-22]
• MacKinnon DP, Fairchild AJ, Fritz MS. Mediation analysis. Annu Rev Psychol. 2007;58:593-614. [ FREE Full text ] [ CrossRef ] [ Medline ]
• MacKinnon DP, Cheong J, Pirlott AG. Statistical mediation analysis. In: Cooper H, Camic PM, Long DL, Panter AT, Rindskopf D, Sher KJ, editors. APA Handbook of Research Methods in Psychology. Washington, DC. American Psychological Association; 2012;313-331.
• Mackinnon DP. Introduction to Statistical Mediation Analysis. New York, NY. Lawrence Erlbaum Associates; 2008.
• Baron RM, Kenny DA. The moderator–mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. J Pers Soc Psychol. 1986;51(6):1173-1182. [ CrossRef ]
• Hayes AF. Introduction to Mediation, Moderation, and Conditional Process Analysis: A Regression-Based Approach. New York, NY. Guilford Press; 2018.
• Charpentier CJ, Aylward J, Roiser JP, Robinson OJ. Enhanced risk aversion, but not loss aversion, in unmedicated pathological anxiety. Biol Psychiatry. Jun 15, 2017;81(12):1014-1022. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Kahneman D, Tversky A. On the interpretation of intuitive probability: a reply to Jonathan Cohen. Cognition. Jan 1979;7(4):409-411. [ CrossRef ]
• Mandrekar JN. Receiver operating characteristic curve in diagnostic test assessment. J Thorac Oncol. Sep 2010;5(9):1315-1316. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Watt J, Borhani R, Katsaggelos AK. Machine Learning Refined: Foundations, Algorithms, and Applications. Cambridge, UK. Cambridge University Press; 2016.
• Viswanath K, Bekalu M, Dhawan D, Pinnamaneni R, Lang J, McLoud R. Individual and social determinants of COVID-19 vaccine uptake. BMC Public Health. Apr 28, 2021;21(1):818. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Judd CM, Kenny DA, McClelland GH. Estimating and testing mediation and moderation in within-subject designs. Psychol Methods. Jun 2001;6(2):115-134. [ CrossRef ] [ Medline ]
• Abdul-Mutakabbir JC, Casey S, Jews V, King A, Simmons K, Hogue MD, et al. A three-tiered approach to address barriers to COVID-19 vaccine delivery in the Black community. Lancet Glob Health. Jun 2021;9(6):e749-e750. [ FREE Full text ] [ CrossRef ] [ Medline ]

Abbreviations

Edited by A Mavragani; submitted 11.04.23; peer-reviewed by ME Visier Alfonso, L Lapp; comments to author 18.05.23; revised version received 08.08.23; accepted 10.01.24; published 18.03.24.

©Nicole L Vike, Sumra Bari, Leandros Stefanopoulos, Shamal Lalvani, Byoung Woo Kim, Nicos Maglaveras, Martin Block, Hans C Breiter, Aggelos K Katsaggelos. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 18.03.2024.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Public Health and Surveillance, is properly cited. The complete bibliographic information, a link to the original publication on https://publichealth.jmir.org, as well as this copyright and license information must be included.

Generate accurate APA citations for free

• Knowledge Base
• APA Style 7th edition
• APA format for academic papers and essays

APA Formatting and Citation (7th Ed.) | Generator, Template, Examples

Published on November 6, 2020 by Raimo Streefkerk . Revised on January 17, 2024.

The 7th edition of the APA Publication Manual provides guidelines for clear communication , citing sources , and formatting documents. This article focuses on paper formatting.

Generate accurate APA citations with Scribbr

Throughout your paper, you need to apply the following APA format guidelines:

• Set page margins to 1 inch on all sides.
• Double-space all text, including headings.
• Indent the first line of every paragraph 0.5 inches.
• Use an accessible font (e.g., Times New Roman 12pt., Arial 11pt., or Georgia 11pt.).
• Include a page number on every page.

Let an expert format your paper

Our APA formatting experts can help you to format your paper according to APA guidelines. They can help you with:

• Margins, line spacing, and indentation
• Font and headings
• Running head and page numbering

Table of contents

How to set up apa format (with template), apa alphabetization guidelines, apa format template [free download], page header, headings and subheadings, reference page, tables and figures, frequently asked questions about apa format.

Scribbr Citation Checker New

The AI-powered Citation Checker helps you avoid common mistakes such as:

• Missing commas and periods
• Incorrect usage of “et al.”
• Ampersands (&) in narrative citations
• Missing reference entries

References are ordered alphabetically by the first author’s last name. If the author is unknown, order the reference entry by the first meaningful word of the title (ignoring articles: “the”, “a”, or “an”).

Why set up APA format from scratch if you can download Scribbr’s template for free?

Student papers and professional papers have slightly different guidelines regarding the title page, abstract, and running head. Our template is available in Word and Google Docs format for both versions.

• Student paper: Word | Google Docs
• Professional paper: Word | Google Docs

In an APA Style paper, every page has a page header. For student papers, the page header usually consists of just a page number in the page’s top-right corner. For professional papers intended for publication, it also includes a running head .

A running head is simply the paper’s title in all capital letters. It is left-aligned and can be up to 50 characters in length. Longer titles are abbreviated .

APA headings have five possible levels. Heading level 1 is used for main sections such as “ Methods ” or “ Results ”. Heading levels 2 to 5 are used for subheadings. Each heading level is formatted differently.

Want to know how many heading levels you should use, when to use which heading level, and how to set up heading styles in Word or Google Docs? Then check out our in-depth article on APA headings .

The title page is the first page of an APA Style paper. There are different guidelines for student and professional papers.

Both versions include the paper title and author’s name and affiliation. The student version includes the course number and name, instructor name, and due date of the assignment. The professional version includes an author note and running head .

For more information on writing a striking title, crediting multiple authors (with different affiliations), and writing the author note, check out our in-depth article on the APA title page .

The abstract is a 150–250 word summary of your paper. An abstract is usually required in professional papers, but it’s rare to include one in student papers (except for longer texts like theses and dissertations).

The abstract is placed on a separate page after the title page . At the top of the page, write the section label “Abstract” (bold and centered). The contents of the abstract appear directly under the label. Unlike regular paragraphs, the first line is not indented. Abstracts are usually written as a single paragraph without headings or blank lines.

Directly below the abstract, you may list three to five relevant keywords . On a new line, write the label “Keywords:” (italicized and indented), followed by the keywords in lowercase letters, separated by commas.

APA Style does not provide guidelines for formatting the table of contents . It’s also not a required paper element in either professional or student papers. If your instructor wants you to include a table of contents, it’s best to follow the general guidelines.

Place the table of contents on a separate page between the abstract and introduction. Write the section label “Contents” at the top (bold and centered), press “Enter” once, and list the important headings with corresponding page numbers.

The APA reference page is placed after the main body of your paper but before any appendices . Here you list all sources that you’ve cited in your paper (through APA in-text citations ). APA provides guidelines for formatting the references as well as the page itself.

Creating APA Style references

Play around with the Scribbr Citation Example Generator below to learn about the APA reference format of the most common source types or generate APA citations for free with Scribbr’s APA Citation Generator .

Formatting the reference page

Write the section label “References” at the top of a new page (bold and centered). Place the reference entries directly under the label in alphabetical order.

Finally, apply a hanging indent , meaning the first line of each reference is left-aligned, and all subsequent lines are indented 0.5 inches.

Tables and figures are presented in a similar format. They’re preceded by a number and title and followed by explanatory notes (if necessary).

Use bold styling for the word “Table” or “Figure” and the number, and place the title on a separate line directly below it (in italics and title case). Try to keep tables clean; don’t use any vertical lines, use as few horizontal lines as possible, and keep row and column labels concise.

Keep the design of figures as simple as possible. Include labels and a legend if needed, and only use color when necessary (not to make it look more appealing).

Check out our in-depth article about table and figure notes to learn when to use notes and how to format them.

The easiest way to set up APA format in Word is to download Scribbr’s free APA format template for student papers or professional papers.

Alternatively, you can watch Scribbr’s 5-minute step-by-step tutorial or check out our APA format guide with examples.

APA Style papers should be written in a font that is legible and widely accessible. For example:

• Times New Roman (12pt.)
• Arial (11pt.)
• Calibri (11pt.)
• Georgia (11pt.)

The same font and font size is used throughout the document, including the running head , page numbers, headings , and the reference page . Text in footnotes and figure images may be smaller and use single line spacing.

You need an APA in-text citation and reference entry . Each source type has its own format; for example, a webpage citation is different from a book citation .

Use Scribbr’s free APA Citation Generator to generate flawless citations in seconds or take a look at our APA citation examples .

Yes, page numbers are included on all pages, including the title page , table of contents , and reference page . Page numbers should be right-aligned in the page header.

To insert page numbers in Microsoft Word or Google Docs, click ‘Insert’ and then ‘Page number’.

APA format is widely used by professionals, researchers, and students in the social and behavioral sciences, including fields like education, psychology, and business.

Be sure to check the guidelines of your university or the journal you want to be published in to double-check which style you should be using.

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the “Cite this Scribbr article” button to automatically add the citation to our free Citation Generator.

Streefkerk, R. (2024, January 17). APA Formatting and Citation (7th Ed.) | Generator, Template, Examples. Scribbr. Retrieved March 20, 2024, from https://www.scribbr.com/apa-style/format/

Is this article helpful?

Raimo Streefkerk

Other students also liked, apa title page (7th edition) | template for students & professionals, creating apa reference entries, beginner's guide to apa in-text citation, unlimited academic ai-proofreading.

✔ Document error-free in 5minutes ✔ Unlimited document corrections ✔ Specialized in correcting academic texts

Help | Advanced Search

Computer Science > Computation and Language

Title: uni-smart: universal science multimodal analysis and research transformer.

Abstract: In scientific research and its application, scientific literature analysis is crucial as it allows researchers to build on the work of others. However, the fast growth of scientific knowledge has led to a massive increase in scholarly articles, making in-depth literature analysis increasingly challenging and time-consuming. The emergence of Large Language Models (LLMs) has offered a new way to address this challenge. Known for their strong abilities in summarizing texts, LLMs are seen as a potential tool to improve the analysis of scientific literature. However, existing LLMs have their own limits. Scientific literature often includes a wide range of multimodal elements, such as molecular structure, tables, and charts, which are hard for text-focused LLMs to understand and analyze. This issue points to the urgent need for new solutions that can fully understand and analyze multimodal content in scientific literature. To answer this demand, we present Uni-SMART (Universal Science Multimodal Analysis and Research Transformer), an innovative model designed for in-depth understanding of multimodal scientific literature. Through rigorous quantitative evaluation across several domains, Uni-SMART demonstrates superior performance over leading text-focused LLMs. Furthermore, our exploration extends to practical applications, including patent infringement detection and nuanced analysis of charts. These applications not only highlight Uni-SMART's adaptability but also its potential to revolutionize how we interact with scientific literature.

Submission history

Access paper:.

• Download PDF
• HTML (experimental)
• Other Formats

References & Citations

• Google Scholar
• Semantic Scholar

BibTeX formatted citation

Bibliographic and Citation Tools

Code, data and media associated with this article, recommenders and search tools.

• Institution

arXivLabs: experimental projects with community collaborators

arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website.

Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them.

Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs .