literature review 1.1

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Chapter 1: Introduction

Learning objectives.

At the conclusion of this chapter, you will be able to:

Identify the purpose of the literature review in the research process
Distinguish between different types of literature reviews

1.1 What is a Literature Review?

Pick up nearly any book on research methods and you will find a description of a literature review. At a basic level, the term implies a survey of factual or nonfiction books, articles, and other documents published on a particular subject. Definitions may be similar across the disciplines, with new types and definitions continuing to emerge. Generally speaking, a literature review is a:

“comprehensive background of the literature within the interested topic area…” ( O’Gorman & MacIntosh, 2015, p. 31 ).
“critical component of the research process that provides an in-depth analysis of recently published research findings in specifically identified areas of interest.” ( House, 2018, p. 109 ).
“written document that presents a logically argued case founded on a comprehensive understanding of the current state of knowledge about a topic of study” ( Machi & McEvoy, 2012, p. 4 ).

As a foundation for knowledge advancement in every discipline, it is an important element of any research project. At the graduate or doctoral level, the literature review is an essential feature of thesis and dissertation, as well as grant proposal writing. That is to say, “A substantive, thorough, sophisticated literature review is a precondition for doing substantive, thorough, sophisticated research…A researcher cannot perform significant research without first understanding the literature in the field.” ( Boote & Beile, 2005, p. 3 ). It is by this means, that a researcher demonstrates familiarity with a body of knowledge and thereby establishes credibility with a reader. An advanced-level literature review shows how prior research is linked to a new project, summarizing and synthesizing what is known while identifying gaps in the knowledge base, facilitating theory development, closing areas where enough research already exists, and uncovering areas where more research is needed. ( Webster & Watson, 2002, p. xiii )

A graduate-level literature review is a compilation of the most significant previously published research on your topic. Unlike an annotated bibliography or a research paper you may have written as an undergraduate, your literature review will outline, evaluate and synthesize relevant research and relate those sources to your own thesis or research question. It is much more than a summary of all the related literature.

It is a type of writing that demonstrate the importance of your research by defining the main ideas and the relationship between them. A good literature review lays the foundation for the importance of your stated problem and research question.

Literature reviews:

define a concept
map the research terrain or scope
systemize relationships between concepts
identify gaps in the literature ( Rocco & Plathotnik, 2009, p. 128 )

The purpose of a literature review is to demonstrate that your research question is meaningful. Additionally, you may review the literature of different disciplines to find deeper meaning and understanding of your topic. It is especially important to consider other disciplines when you do not find much on your topic in one discipline. You will need to search the cognate literature before claiming there is “little previous research” on your topic.

Well developed literature reviews involve numerous steps and activities. The literature review is an iterative process because you will do at least two of them: a preliminary search to learn what has been published in your area and whether there is sufficient support in the literature for moving ahead with your subject. After this first exploration, you will conduct a deeper dive into the literature to learn everything you can about the topic and its related issues.

Literature Review Tutorial

A video titled "Literature Reviews: An overview for graduate students." Video here: https://www.lib.ncsu.edu/tutorials/litreview/. Transcript available here: https://siskel.lib.ncsu.edu/RIS/instruction/litreview/litreview.txt

1.2 Literature Review Basics

An effective literature review must:

Methodologically analyze and synthesize quality literature on a topic
Provide a firm foundation to a topic or research area
Provide a firm foundation for the selection of a research methodology
Demonstrate that the proposed research contributes something new to the overall body of knowledge of advances the research field’s knowledge base. ( Levy & Ellis, 2006 ).

All literature reviews, whether they are qualitative, quantitative or both, will at some point:

Introduce the topic and define its key terms
Establish the importance of the topic
Provide an overview of the amount of available literature and its types (for example: theoretical, statistical, speculative)
Identify gaps in the literature
Point out consistent finding across studies
Arrive at a synthesis that organizes what is known about a topic
Discusses possible implications and directions for future research

1.3 Types of Literature Reviews

There are many different types of literature reviews, however there are some shared characteristics or features. Remember a comprehensive literature review is, at its most fundamental level, an original work based on an extensive critical examination and synthesis of the relevant literature on a topic. As a study of the research on a particular topic, it is arranged by key themes or findings, which may lead up to or link to the research question. In some cases, the research question will drive the type of literature review that is undertaken.

The following section includes brief descriptions of the terms used to describe different literature review types with examples of each. The included citations are open access, Creative Commons licensed or copyright-restricted.

1.3.1 Types of Review

1.3.1.1 conceptual.

Guided by an understanding of basic issues rather than a research methodology. You are looking for key factors, concepts or variables and the presumed relationship between them. The goal of the conceptual literature review is to categorize and describe concepts relevant to your study or topic and outline a relationship between them. You will include relevant theory and empirical research.

Examples of a Conceptual Review:

Education : The formality of learning science in everyday life: A conceptual literature review. ( Dohn, 2010 ).
Education : Are we asking the right questions? A conceptual review of the educational development literature in higher education. ( Amundsen & Wilson, 2012 ).

Figure 1.1 shows a diagram of possible topics and subtopics related to the use of information systems in education. In this example, constructivist theory is a concept that might influence the use of information systems in education. A related but separate concept the researcher might want to explore are the different perspectives of students and teachers regarding the use of information systems in education.

1.3.1.2 Empirical

An empirical literature review collects, creates, arranges, and analyzes numeric data reflecting the frequency of themes, topics, authors and/or methods found in existing literature. Empirical literature reviews present their summaries in quantifiable terms using descriptive and inferential statistics.

Examples of an Empirical Review:

Nursing : False-positive findings in Cochrane meta-analyses with and without application of trial sequential analysis: An empirical review. ( Imberger, Thorlund, Gluud, & Wettersley, 2016 ).
Education : Impediments of e-learning adoption in higher learning institutions of Tanzania: An empirical review ( Mwakyusa & Mwalyagile, 2016 ).

1.3.1.3 Exploratory

Unlike a synoptic literature review, the purpose here is to provide a broad approach to the topic area. The aim is breadth rather than depth and to get a general feel for the size of the topic area. A graduate student might do an exploratory review of the literature before beginning a synoptic, or more comprehensive one.

Examples of an Exploratory Review:

Education : University research management: An exploratory literature review. ( Schuetzenmeister, 2010 ).
Education : An exploratory review of design principles in constructivist gaming learning environments. ( Rosario & Widmeyer, 2009 ).

1.3.1.4 Focused

A type of literature review limited to a single aspect of previous research, such as methodology. A focused literature review generally will describe the implications of choosing a particular element of past research, such as methodology in terms of data collection, analysis and interpretation.

Examples of a Focused Review:

Nursing : Clinical inertia in the management of type 2 diabetes mellitus: A focused literature review. ( Khunti, Davies, & Khunti, 2015 ).
Education : Language awareness: Genre awareness-a focused review of the literature. ( Stainton, 1992 ).

1.3.1.5 Integrative

Critiques past research and draws overall conclusions from the body of literature at a specified point in time. Reviews, critiques, and synthesizes representative literature on a topic in an integrated way. Most integrative reviews are intended to address mature topics or emerging topics. May require the author to adopt a guiding theory, a set of competing models, or a point of view about a topic. For more description of integrative reviews, see Whittemore & Knafl (2005).

Examples of an Integrative Review:

Nursing : Interprofessional teamwork and collaboration between community health workers and healthcare teams: An integrative review. ( Franklin, Bernhardt, Lopez, Long-Middleton, & Davis, 2015 ).
Education : Exploring the gap between teacher certification and permanent employment in Ontario: An integrative literature review. ( Brock & Ryan, 2016 ).

1.3.1.6 Meta-analysis

A subset of a systematic review, that takes findings from several studies on the same subject and analyzes them using standardized statistical procedures to pool together data. Integrates findings from a large body of quantitative findings to enhance understanding, draw conclusions, and detect patterns and relationships. Gather data from many different, independent studies that look at the same research question and assess similar outcome measures. Data is combined and re-analyzed, providing a greater statistical power than any single study alone. It’s important to note that not every systematic review includes a meta-analysis but a meta-analysis can’t exist without a systematic review of the literature.

Examples of a Meta-Analysis:

Education : Efficacy of the cooperative learning method on mathematics achievement and attitude: A meta-analysis research. ( Capar & Tarim, 2015 ).
Nursing : A meta-analysis of the effects of non-traditional teaching methods on the critical thinking abilities of nursing students. ( Lee, Lee, Gong, Bae, & Choi, 2016 ).
Education : Gender differences in student attitudes toward science: A meta-analysis of the literature from 1970 to 1991. ( Weinburgh, 1995 ).

1.3.1.7 Narrative/Traditional

An overview of research on a particular topic that critiques and summarizes a body of literature. Typically broad in focus. Relevant past research is selected and synthesized into a coherent discussion. Methodologies, findings and limits of the existing body of knowledge are discussed in narrative form. Sometimes also referred to as a traditional literature review. Requires a sufficiently focused research question. The process may be subject to bias that supports the researcher’s own work.

Examples of a Narrative/Traditional Review:

Nursing : Family carers providing support to a person dying in the home setting: A narrative literature review. ( Morris, King, Turner, & Payne, 2015 ).
Education : Adventure education and Outward Bound: Out-of-class experiences that make a lasting difference. ( Hattie, Marsh, Neill, & Richards, 1997 ).
Education : Good quality discussion is necessary but not sufficient in asynchronous tuition: A brief narrative review of the literature. ( Fear & Erikson-Brown, 2014 ).
Nursing : Outcomes of physician job satisfaction: A narrative review, implications, and directions for future research. ( Williams & Skinner, 2003 ).

1.3.1.8 Realist

Aspecific type of literature review that is theory-driven and interpretative and is intended to explain the outcomes of a complex intervention program(s).

Examples of a Realist Review:

Nursing : Lean thinking in healthcare: A realist review of the literature. ( Mazzacato, Savage, Brommels, 2010 ).
Education : Unravelling quality culture in higher education: A realist review. ( Bendermacher, Egbrink, Wolfhagen, & Dolmans, 2017 ).

1.3.1.9 Scoping

Tend to be non-systematic and focus on breadth of coverage conducted on a topic rather than depth. Utilize a wide range of materials; may not evaluate the quality of the studies as much as count the number. One means of understanding existing literature. Aims to identify nature and extent of research; preliminary assessment of size and scope of available research on topic. May include research in progress.

Examples of a Scoping Review:

Nursing : Organizational interventions improving access to community-based primary health care for vulnerable populations: A scoping review. ( Khanassov, Pluye, Descoteaux, Haggerty, Russell, Gunn, & Levesque, 2016 ).
Education : Interdisciplinary doctoral research supervision: A scoping review. ( Vanstone, Hibbert, Kinsella, McKenzie, Pitman, & Lingard, 2013 ).
Nursing : A scoping review of the literature on the abolition of user fees in health care services in Africa. ( Ridde, & Morestin, 2011 ).

1.3.1.10 Synoptic

Unlike an exploratory review, the purpose is to provide a concise but accurate overview of all material that appears to be relevant to a chosen topic. Both content and methodological material is included. The review should aim to be both descriptive and evaluative. Summarizes previous studies while also showing how the body of literature could be extended and improved in terms of content and method by identifying gaps.

Examples of a Synoptic Review:

Education : Theoretical framework for educational assessment: A synoptic review. ( Ghaicha, 2016 ).
Education : School effects research: A synoptic review of past efforts and some suggestions for the future. ( Cuttance, 1981 ).

1.3.1.11 Systematic Review

A rigorous review that follows a strict methodology designed with a presupposed selection of literature reviewed. Undertaken to clarify the state of existing research, the evidence, and possible implications that can be drawn from that. Using comprehensive and exhaustive searching of the published and unpublished literature, searching various databases, reports, and grey literature. Transparent and reproducible in reporting details of time frame, search and methods to minimize bias. Must include a team of at least 2-3 and includes the critical appraisal of the literature. For more description of systematic reviews, including links to protocols, checklists, workflow processes, and structure see “ A Young Researcher’s Guide to a Systematic Review “.

Examples of a Systematic Review:

Education : The potentials of using cloud computing in schools: A systematic literature review ( Hartmann, Braae, Pedersen, & Khalid, 2017 )
Nursing : Is butter back? A systematic review and meta-analysis of butter consumption and risk of cardiovascular disease, diabetes, and total mortality. ( Pimpin, Wu, Haskelberg, Del Gobbo, & Mozaffarian, 2016 ).
Education : The use of research to improve professional practice: a systematic review of the literature. ( Hemsley-Brown & Sharp, 2003 ).
Nursing : Using computers to self-manage type 2 diabetes. ( Pal, Eastwood, Michie, Farmer, Barnard, Peacock, Wood, Inniss, & Murray, 2013 ).

1.3.1.12 Umbrella/Overview of Reviews

Compiles evidence from multiple systematic reviews into one document. Focuses on broad condition or problem for which there are competing interventions and highlights reviews that address those interventions and their effects. Often used in recommendations for practice.

Examples of an Umbrella/Overview Review:

Education : Reflective practice in healthcare education: An umbrella review. ( Fragknos, 2016 ).
Nursing : Systematic reviews of psychosocial interventions for autism: an umbrella review. ( Seida, Ospina, Karkhaneh, Hartling, Smith, & Clark, 2009 ).

For a brief discussion see “ Not all literature reviews are the same ” (Thomson, 2013).

1.4 Why do a Literature Review?

The purpose of the literature review is the same regardless of the topic or research method. It tests your own research question against what is already known about the subject.

1.4.1 First – It’s part of the whole. Omission of a literature review chapter or section in a graduate-level project represents a serious void or absence of critical element in the research process.

The outcome of your review is expected to demonstrate that you:

can systematically explore the research in your topic area
can read and critically analyze the literature in your discipline and then use it appropriately to advance your own work
have sufficient knowledge in the topic to undertake further investigation

1.4.2 Second – It’s good for you!

You improve your skills as a researcher
You become familiar with the discourse of your discipline and learn how to be a scholar in your field
You learn through writing your ideas and finding your voice in your subject area
You define, redefine and clarify your research question for yourself in the process

1.4.3 Third – It’s good for your reader. Your reader expects you to have done the hard work of gathering, evaluating and synthesizes the literature. When you do a literature review you:

Set the context for the topic and present its significance
Identify what’s important to know about your topic – including individual material, prior research, publications, organizations and authors.
Demonstrate relationships among prior research
Establish limitations of existing knowledge
Analyze trends in the topic’s treatment and gaps in the literature

1.4.4 Why do a literature review?

To locate gaps in the literature of your discipline
To avoid reinventing the wheel
To carry on where others have already been
To identify other people working in the same field
To increase your breadth of knowledge in your subject area
To find the seminal works in your field
To provide intellectual context for your own work
To acknowledge opposing viewpoints
To put your work in perspective
To demonstrate you can discover and retrieve previous work in the area

1.5 Common Literature Review Errors

Graduate-level literature reviews are more than a summary of the publications you find on a topic. As you have seen in this brief introduction, literature reviews are a very specific type of research, analysis, and writing. We will explore these topics more in the next chapters. Some things to keep in mind as you begin your own research and writing are ways to avoid the most common errors seen in the first attempt at a literature review. For a quick review of some of the pitfalls and challenges a new researcher faces when he/she begins work, see “ Get Ready: Academic Writing, General Pitfalls and (oh yes) Getting Started! ”.

As you begin your own graduate-level literature review, try to avoid these common mistakes:

Accepts another researcher’s finding as valid without evaluating methodology and data
Contrary findings and alternative interpretations are not considered or mentioned
Findings are not clearly related to one’s own study, or findings are too general
Insufficient time allowed to define best search strategies and writing
Isolated statistical results are simply reported rather than synthesizing the results
Problems with selecting and using most relevant keywords, subject headings and descriptors
Relies too heavily on secondary sources
Search methods are not recorded or reported for transparency
Summarizes rather than synthesizes articles

In conclusion, the purpose of a literature review is three-fold:

to survey the current state of knowledge or evidence in the area of inquiry,
to identify key authors, articles, theories, and findings in that area, and
to identify gaps in knowledge in that research area.

A literature review is commonly done today using computerized keyword searches in online databases, often working with a trained librarian or information expert. Keywords can be combined using the Boolean operators, “and”, “or” and sometimes “not” to narrow down or expand the search results. Once a list of articles is generated from the keyword and subject heading search, the researcher must then manually browse through each title and abstract, to determine the suitability of that article before a full-text article is obtained for the research question.

Literature reviews should be reasonably complete, and not restricted to a few journals, a few years, or a specific methodology or research design. Reviewed articles may be summarized in the form of tables, and can be further structured using organizing frameworks such as a concept matrix.

A well-conducted literature review should indicate whether the initial research questions have already been addressed in the literature, whether there are newer or more interesting research questions available, and whether the original research questions should be modified or changed in light of findings of the literature review.

The review can also provide some intuitions or potential answers to the questions of interest and/or help identify theories that have previously been used to address similar questions and may provide evidence to inform policy or decision-making. ( Bhattacherjee, 2012 ).

Read Abstract 1. Refer to Types of Literature Reviews. What type of literature review do you think this study is and why? See the Answer Key for the correct response.

Nursing : To describe evidence of international literature on the safe care of the hospitalised child after the World Alliance for Patient Safety and list contributions of the general theoretical framework of patient safety for paediatric nursing.

An integrative literature review between 2004 and 2015 using the databases PubMed, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Scopus, Web of Science and Wiley Online Library, and the descriptors Safety or Patient safety, Hospitalised child, Paediatric nursing, and Nursing care.

Thirty-two articles were analysed, most of which were from North American, with a descriptive approach. The quality of the recorded information in the medical records, the use of checklists, and the training of health workers contribute to safe care in paediatric nursing and improve the medication process and partnerships with parents.

General information available on patient safety should be incorporated in paediatric nursing care. ( Wegner, Silva, Peres, Bandeira, Frantz, Botene, & Predebon, 2017 ).

Read Abstract 2. Refer to Types of Literature Reviews. What type of lit review do you think this study is and why? See the Answer Key for the correct response.

Education : The focus of this paper centers around timing associated with early childhood education programs and interventions using meta-analytic methods. At any given assessment age, a child’s current age equals starting age, plus duration of program, plus years since program ended. Variability in assessment ages across the studies should enable everyone to identify the separate effects of all three time-related components. The project is a meta-analysis of evaluation studies of early childhood education programs conducted in the United States and its territories between 1960 and 2007. The population of interest is children enrolled in early childhood education programs between the ages of 0 and 5 and their control-group counterparts. Since the data come from a meta-analysis, the population for this study is drawn from many different studies with diverse samples. Given the preliminary nature of their analysis, the authors cannot offer conclusions at this point. ( Duncan, Leak, Li, Magnuson, Schindler, & Yoshikawa, 2011 ).

Test Yourself

See Answer Key for the correct responses.

The purpose of a graduate-level literature review is to summarize in as many words as possible everything that is known about my topic.

A literature review is significant because in the process of doing one, the researcher learns to read and critically assess the literature of a discipline and then uses it appropriately to advance his/her own research.

Read the following abstract and choose the correct type of literature review it represents.

Nursing: E-cigarette use has become increasingly popular, especially among the young. Its long-term influence upon health is unknown. Aim of this review has been to present the current state of knowledge about the impact of e-cigarette use on health, with an emphasis on Central and Eastern Europe. During the preparation of this narrative review, the literature on e-cigarettes available within the network PubMed was retrieved and examined. In the final review, 64 research papers were included. We specifically assessed the construction and operation of the e-cigarette as well as the chemical composition of the e-liquid; the impact that vapor arising from the use of e-cigarette explored in experimental models in vitro; and short-term effects of use of e-cigarettes on users’ health. Among the substances inhaled by the e-smoker, there are several harmful products, such as: formaldehyde, acetaldehyde, acroleine, propanal, nicotine, acetone, o-methyl-benzaldehyde, carcinogenic nitrosamines. Results from experimental animal studies indicate the negative impact of e-cigarette exposure on test models, such as ascytotoxicity, oxidative stress, inflammation, airway hyper reactivity, airway remodeling, mucin production, apoptosis, and emphysematous changes. The short-term impact of e-cigarettes on human health has been studied mostly in experimental setting. Available evidence shows that the use of e-cigarettes may result in acute lung function responses (e.g., increase in impedance, peripheral airway flow resistance) and induce oxidative stress. Based on the current available evidence, e-cigarette use is associated with harmful biologic responses, although it may be less harmful than traditional cigarettes. (J ankowski, Brożek, Lawson, Skoczyński, & Zejda, 2017 ).

Meta-analysis
Exploratory

Education: In this review, Mary Vorsino writes that she is interested in keeping the potential influences of women pragmatists of Dewey’s day in mind while presenting modern feminist re readings of Dewey. She wishes to construct a narrowly-focused and succinct literature review of thinkers who have donned a feminist lens to analyze Dewey’s approaches to education, learning, and democracy and to employ Dewey’s works in theorizing on gender and education and on gender in society. This article first explores Dewey as both an ally and a problematic figure in feminist literature and then investigates the broader sphere of feminist pragmatism and two central themes within it: (1) valuing diversity, and diverse experiences; and (2) problematizing fixed truths. ( Vorsino, 2015 ).

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Writing a Literature Review

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A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

An introductory paragraph that explains what your working topic and thesis is
A forecast of key topics or texts that will appear in the review
Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
Critically Evaluate: Mention the strengths and weaknesses of your sources
Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

Summarize the key findings you have taken from the literature and emphasize their significance
Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
Qualitative versus quantitative research
Empirical versus theoretical scholarship
Divide the research by sociological, historical, or cultural sources
Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

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Module 11 - Writing Your Literature Review

Module 1 - Introduction
Module 2 - UNE Induction
Module 3 - Research Integrity and Ethics
Module 4 - Getting Organised
Module 5 - Data Management
Module 6 - Research Software
Module 7 - The Research Question
Module 8 - Deciding Where To Search
Module 9 - Evaluating Sources
Module 10 - Writing Skills
Module 12 - Publishing
Module 13 - Communicating Your Research
Module 14 - Tracking Your Research Impact
Module 15 - Pathways and Training
Workbook, Resources and Evaluation

Writing Your Literature Review

A literature review is more than a summary of past research or an annotated bibliography. It is a work of synthesis which provides the context for your own investigations. In your literature review, you should:

Clarify your understanding of the field
Justify the theoretical and methodological approach of your research
Place your research within a broader context
Identify gaps in the current knowledge on your topic
Evaluate the results of previous research
Define key concepts and ideas
Identify research in related areas that is general or transferable to your topic
Identify relevant methodological issues

Learning outcomes

Upon completion of this module, you will be able to:

Compare the different types of literature reviews and select the appropriate review format for your field of research
Identify, track and troubleshoot literature review searches relevant to your research topic
Assess literature sources for authenticity
Categorise literature using a chosen method (e.g. thematic categories)
Use note making skills to summarise each source of literature
Critically evaluate sources of literature for their strengths, weaknesses and contributions to your research topic
Synthesise multiple sources of information to inform your position
Determine gaps in the literature search, relevant to your topic
Begin constructing your literature review

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11.1 Types of literature reviews

This content was adapted from Griffith University .

A literature review ensures that you are at least familiar with the body of research in your field before starting your own investigations. Writing a literature review also provides practice in critical thinking. Once you have applied critical thinking skills to the findings of past researchers, you are in a better position to apply these same skills to your own work.

You need to think of your literature review as a process – the steps you need to go through to identify and work with the literature, through to the final, written version (Figure 11). As you work through each of the steps, you should be writing all the time: taking notes, summarising sources, reflecting on your reading, keeping a journal of your ideas, and sharing your ideas with your supervisors and fellow researchers.

Figure 11. The process of a literature review

11.1.1 Narrative or traditional literature reviews

Critique and summarise a body of literature about the thesis topic
Literature is researched from the relevant databases and is generally very selective in the material used
Criteria for literature selection for a narrative review is not always made open to the reader
These reviews are very useful in gathering and synthesising the literature located
Principle purpose of a narrative review is to give the author and reader a comprehensive overview of the topic and to highlight significant areas of research, help identify gaps in the research and help to refine and define research questions
Narrative approach differs from a systematic approach in the notation of search methods criteria for selection. This can leave narrative reviews open to suggestions of bias

11.1.2 Systematic reviews

SAGE Research Methods , defines a systematic review as "A review of the literature that is conducted in a methodical manner based on a pre-specified protocol with the aim of synthesising the retrieved information, often by means of a meta-analysis."

11.1.3 Scoping Reviews

Similar to a systematic literature review
Key difference is that there are no restrictions on the materials sourced
Purpose is to find ALL the materials on the topic
When undertaking a scoping review it is important to systematise your search strategies to ensure you can replicate your searches and to attend to any gaps that appear in results
When reading and sorting the results, apply some of the measures used in a systematic review so that your search results are sorted by key themes and are well organised

11.1.4 Cochrane Reviews

Cochrane Reviews are systematic reviews of primary research in human health care and health policy
Internationally recognised as the highest standard in evidence-based health care
Investigate the effects of interventions for prevention, treatment and rehabilitation
Assess the accuracy of a diagnostic test for a given condition in a specific patient group and setting

11.1.5 Campbell Collaboration

Campbell Collaboration is an international research network that produces systematic reviews of the effects of social interventions in Crime & Justice, Education, International Development, and Social Welfare

If you have not done so already, talk to your supervisor about the type of literature review you need to write. You should also take time to decide what the boundaries/limits of your literature review will be – it is very easy to get caught in a cycle of sourcing literature that goes beyond the scope of your study. By setting boundaries (in consultation with your supervisors) your literature review process will be focused and you are less likely to be overwhelmed by the volume of information available.

11.2 Identify the literature

Refer to the mind map you created in Workbook Activity 7.1 (Formulating your research question) and use the topics, themes and concepts you identified to begin sourcing literature.

Are you getting too few results?
Or perhaps too many?
Maybe not the right kind of results?

If you answered yes to any of the above questions, experiment with the search parameters to see if you can change the results you are returning. Try the following:

Use synonyms (refer your answers in Workbook Activity 7.2 Developing key search terms )
Use faceted searching, for example limit the year range or publication type (this is often in the left hand column)
Use the advanced search to only look in a certain area, for example search just the title, abstract, and subject headings instead of the whole article

Feeling a little lost? Revisit Module 7 (The Research Question) for more ideas on how to refine your search parameters. You can also attend a Library workshop on ' search skills for researchers '.

11.2.1 Keep track of your searches

Now is a good time to review your account settings with databases you regularly use ( Module 8 Deciding where to search ) or, based on your searches in 11.2 ( Identify the literature ), set up a new account in a recently discovered database. Remember, you can set alerts so you receive emails about:

Table of Contents
Author citation alerts
Document citation alerts
Search alerts

Now is also a good time to update your records of searches running across databases – you may choose to set up a new record specifically for your literature review searches. Remember, these records should detail the:

Day searched
Database searched
Search query run
Limiters applied during the search

Feeling a little lost? Revisit Module 7 The Research Question for more ideas on how to refine your search parameters.

11.3 Validate the literature

Before progressing further with sources of information, you should perform the T.R.A.A.P test to ensure the information is current (timely), relevant, accurate, authorship is reputable, and that it serves a clear purpose for the topic and your literature review.

Feeling a little lost? Revisit Module 9 Evaluating Sources to refresh your T.R.A.A.P skills.

11.4 Categorise the literature

Once your initial search has identified some of the literature that is relevant for your study, the next step is to categorise the literature. Recall from Module 7 Activity 6 (Keeping a track of your database searches) that the sources may be categorised in a number of different ways. Can you think of a way to categorise the sources you are using for your own research? The method you choose will depend on the type of literature that is relevant for the study or the particular focus of the study.

Consider what you already know about your topic and your specific research question(s) (refer to your workbook activities for Module 7 The Research Question ):

What are the major themes that have relevance for your own work? Start to identify the work related to your particular field of research
Who are the key authorities, experts or writers – the giants – in your field of research?
Note any areas of consensus or disagreement between different writers

Remember, you can also attend a Library workshop on ' search skills for researchers '.

11.5 Summarise the literature

Choose one of the sources you have categorised and write a summary of the source.

Revisit Module 10 Writing Skills and your Workbook activities to assist in finding the best way to write summaries to suit you.

11.6 Evaluate, synthesise, and determine gaps in the literature

It is important to not only describe the content of the sources that you read but also to develop a critical stance on the literature that you review. Remember when evaluating literature, you are considering the strengths of the study, the significance and contribution of the information to your field of research and identifying the limitations, flaws or weaknesses.

Revisit Module 9 Evaluating Sources to refresh your memory on evaluating literature.

Using the same source as used in activity 5 (Summarise the literature) , evaluate the research/article/source using the questions from Module 9 as a guide.

Once you have categorised, summarised, and evaluated a number of the identified texts, start to take note of any patterns you observe in what you have read and any gaps where you can insert your own study. You may find that there is a gap where the research is incomplete; you may find a need to apply a new theory to an old problem; or you may establish a need to look at a topic from a new angle or perspective.

11.7 The product: The structure of the traditional literature review

Your literature review may be a chapter on its own, it may be embedded in different chapters, or it may be separated into chapters organised around different topics or themes. For a thesis by publication, each publication/manuscript will include its own literature review, and the introduction to the whole thesis will need to include its own review of the literature that pulls together the themes in each publication/manuscript.

Each of these different formats will have a basic generic structure of introduction, body and conclusion.

11.7.1 Introduction

In the introduction section of the literature review, you should define the general topic and provide an appropriate context for reviewing the literature. Summarise the overall trends that have emerged from your review of the literature and highlight the significance of your review. Establish your reason for reviewing the literature and outline the scope and organisation of the current review.

Find a thesis in your discipline in Research UNE ( RUNE ) or ask your supervisors to recommend a good thesis to look at. How is the literature review structured? Is it a stand-alone review? Embedded in chapters? Thesis by publication? Read the introduction of the literature review. Can you identify any of the following elements in the introduction?

The general topic or area of concern
Overall trends in the published literature
Significance of the present review
The writer’s purpose for reviewing the literature
The scope and organisation of the review

11.7.2 Body

In the body of the literature review, group the literature (research studies, reviews, theoretical articles, case studies, etc.) according to common denominators.

For example, you may group the studies in terms of qualitative versus quantitative approaches, major findings, conclusions of authors or chronology of previous work.

Arrange the literature review following a logical sequence.

For example, you may decide to begin by reviewing the theoretical literature before moving on to the empirical research. As you present the research, critically evaluate the studies, discussing strengths, weaknesses and limitations.

You can help the reader by using appropriate headings and subheadings to indicate the topics and subtopics of different sections of the review, and by using transition signals and linking words to make explicit the logical connections between your ideas. See the fact sheet on Connecting your ideas for more information on transition words.

Using the same thesis as in the previous activity, skim through the body of the review. Can you identify a distinct pattern of organisation? What principle was used to organise the review? How do you think you will organise your own literature review?

11.7.3 Conclusion

In the conclusion section of the literature review, you should

Summarise the major contributions of the studies/ research to the body of knowledge under review
Maintain the focus that you established in the introduction
Evaluate the current state of knowledge, pointing out major flaws in methodology or gaps in research, inconsistencies in theory and findings, and areas pertinent to future study
Make explicit the links between the review and your own research project to justify your study

Using the same thesis as in the previous activities, read the concluding section of the literature review. How does the writer identify the gaps in the literature that the review has highlighted? How does the writer justify the present study?

11.8 Summary

Hopefully by now, you have an idea about how you can get started on your own literature review. If you have already started, assess your own draft. For example, what logic have you used to structure the review? Have you used signposts to guide the reader? Are there clear links between the literature review and your own study? Repeat this process until you are satisfied with your draft. Perhaps you can exchange drafts with another Masters/PhD student for additional feedback, before submitting your draft to your supervisors.

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Module 1: Types of Reviews

Conducting a Literature Review

All reviews follow a familiar process:

Find and examine existing literature reviews.
Formulate a research question.
Search for sources.
Assess the quality of your results and select your sources.
Synthesize the important information from your sources.
Analyze what you’ve found.

Find and Examine Existing Literature Reviews

Prior to starting your own research, you will want to look at existing literature reviews – this is especially important so that you don’t duplicate existing work. It can also be helpful to look at the approaches taken for literature reviews similar to your own topic or discipline. Below are some examples of locating existing reviews.

Search in academic journal articles – All published articles have literature reviews. They are a key component of an academic journal article as they create the foundation for new research and establish credibility for the authors. Authors need to demonstrate to peer reviewers and readers that they have a good command of the existing literature, and they have identified a gap they will fill with the present study.
Identify clusters of citations in published articles – Sometimes, literature reviews are clearly labelled as such with a descriptive heading, but more often, they are presented as part of the introduction or background section at the beginning of the article. The telltale sign that you are looking at the literature review is the presence of clusters of citations.
Search for “literature review” articles – While most literature reviews are done in the context of laying the groundwork for an original study, some are published as articles in their own right. When searching for this type of article you can limit part of your search strategy to look for the term “ literature review ” in the title of the article. See Figure 1.1 below.

Formulate a Research Question

In general, your research question will tackle the problem you are trying to address by conducting the review. Since constructing a research question can be an in-depth process, we go over it in more detail in Module 2: Formulating a Research Question and Searching for Sources .

Conduct Your Review Using the SALSA Framework

Once you have a research question, there are four stages you can follow when conducting your chosen review. These are known as the SALSA Framework : s earch, a ppraisa l, s ynthesis and a nalysis.

Here is a quick summary of the SALSA steps.

Wait, What happened to the “L” in SALSA?

Did you notice the missing L? We did too! The authors, Grant and Booth (2009) created a simple analytical framework for conducting reviews: S earch, A ppraisal, S ynthesis and A nalysis. SASA, however, doesn’t make a memorable acronym, and Academics love a good acronym, so they derived the “L” from the last letter of appraisal: S earch, A ppraisa L , S ynthesis and A nalysis (SALSA).

The examining and combining of information with other information to produce a final interpretation, theory or conclusion.

An academic journal or scholarly journal is a periodical publication in which research and scholarship relating to a particular academic discipline is published. Academic journals serve as permanent and transparent forums for the presentation, scrutiny, and discussion of research. They are usually peer-reviewed.

Advanced Research Skills: Conducting Literature and Systematic Reviews Copyright © 2021 by Kelly Dermody; Cecile Farnum; Daniel Jakubek; Jo-Anne Petropoulos; Jane Schmidt; and Reece Steinberg is licensed under a Creative Commons Attribution 4.0 International License , except where otherwise noted.

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4. Literature Reviews
4.1. Introduction to Literature Reviews
4.2. What is a Literature Review?
4.3. How to Get Started
4.4. Where to Find the Literature
4.5. Evaluating Sources
4.6. Documenting Sources
4.7. Synthesizing Sources
4.8. Writing the Literature Review
4.9. Concluding Thoughts on Literature Reviews
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Introduction to Literature Reviews

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Learning Objectives

At the conclusion of this chapter, you will be able to:

Identify the purpose of the literature review in the research process;
Distinguish between different types of literature reviews.

What is a Literature Review?

“comprehensive background of the literature within the interested topic area…” ( O’Gorman & MacIntosh, 2015, p. 31 [https://edtechbooks.org/-EaoJ] ).
“critical component of the research process that provides an in-depth analysis of recently published research findings in specifically identified areas of interest.” ( House, 2018, p. 109 [https://edtechbooks.org/-EaoJ] ).
“written document that presents a logically argued case founded on a comprehensive understanding of the current state of knowledge about a topic of study” ( Machi & McEvoy, 2012, p. 4 [https://edtechbooks.org/-EaoJ] ).

As a foundation for knowledge advancement in every discipline, it is an important element of any research project. At the graduate or doctoral level, the literature review is an essential feature of thesis and dissertation, as well as grant proposal writing. That is to say, “A substantive, thorough, sophisticated literature review is a precondition for doing substantive, thorough, sophisticated research…A researcher cannot perform significant research without first understanding the literature in the field.” ( Boote & Beile, 2005, p. 3 [https://edtechbooks.org/-EaoJ] ). It is by this means, that a researcher demonstrates familiarity with a body of knowledge and thereby establishes credibility with a reader. An advanced-level literature review shows how prior research is linked to a new project, summarizing and synthesizing what is known while identifying gaps in the knowledge base, facilitating theory development, closing areas where enough research already exists, and uncovering areas where more research is needed. ( Webster & Watson, 2002, p. xiii [https://edtechbooks.org/-EaoJ] )

Literature reviews do the following:

define a concept
map the research terrain or scope
systemize relationships between concepts
identify gaps in the literature ( Rocco & Plathotnik, 2009, p. 128 [https://edtechbooks.org/-EaoJ] )

In the context of a research study, the purpose of a literature review is to demonstrate that your research question is meaningful. Additionally, you may review the literature of different disciplines to find deeper meaning and understanding of your topic. It is especially important to consider other disciplines when you do not find much on your topic in one discipline. You will need to search the cognate literature before claiming there is “little previous research” on your topic.

Literature Review Tutorial

Literature Review Basics

An effective literature review must:

Methodologically analyze and synthesize quality literature on a topic
Provide a firm foundation to a topic or research area
Provide a firm foundation for the selection of a research methodology
Demonstrate that the proposed research contributes something new to the overall body of knowledge of advances the research field’s knowledge base. ( Levy & Ellis, 2006 [https://edtechbooks.org/-EaoJ] ).

All literature reviews, whether they are qualitative, quantitative or both, will at some point:

Introduce the topic and define its key terms
Establish the importance of the topic
Provide an overview of the amount of available literature and its types (for example: theoretical, statistical, speculative)
Identify gaps in the literature
Point out consistent finding across studies
Arrive at a synthesis that organizes what is known about a topic
Discusses possible implications and directions for future research

Types of Literature Reviews

There are many different types of literature reviews, however there are some shared characteristics or features that all share. Remember a comprehensive literature review is, at its most fundamental level, an original work based on an extensive critical examination and synthesis of the relevant literature on a topic. As a study of the research on a particular topic, it is arranged by key themes or findings, which may lead up to or link to the research question. In some cases, the research question will drive the type of literature review that is undertaken.

Guided by an understanding of basic issues rather than a research methodology, the writer of a conceptual literature review is looking for key factors, concepts or variables and the presumed relationship between them. The goal of the conceptual literature review is to categorize and describe concepts relevant to the study or topic and outline a relationship between them, including relevant theory and empirical research.

Examples of a Conceptual Review:

The formality of learning science in everyday life: A conceptual literature review ( Dohn, 2010 [https://edtechbooks.org/-EaoJ] ).
Are we asking the right questions? A conceptual review of the educational development literature in higher education ( Amundsen & Wilson, 2012 [https://edtechbooks.org/-EaoJ] ).

Examples of an Empirical Review:

Impediments of e-learning adoption in higher learning institutions of Tanzania: An empirical review ( Mwakyusa & Mwalyagile, 2016 [https://edtechbooks.org/-EaoJ] ).
Exploratory

The purpose of an exploratory review is to provide a broad approach to the topic area. The aim is breadth rather than depth and to get a general feel for the size of the topic area. A graduate student might do an exploratory review of the literature before beginning a more comprehensive one (e.g., synoptic).

Examples of an Exploratory Review:

University research management: An exploratory literature review ( Schuetzenmeister, 2010 [https://edtechbooks.org/-EaoJ] ).
An exploratory review of design principles in constructivist gaming learning environments ( Rosario & Widmeyer, 2009 [https://edtechbooks.org/-EaoJ] ).

This type of literature review is limited to a single aspect of previous research, such as methodology. A focused literature review generally will describe the implications of choosing a particular element of past research, such as methodology in terms of data collection, analysis, and interpretation.

Examples of a Focused Review:

Language awareness: Genre awareness-a focused review of the literature ( Stainton, 1992 [https://edtechbooks.org/-EaoJ] ).

Integrative

An integrative review critiques past research and draws overall conclusions from the body of literature at a specified point in time. As such, it reviews, critiques, and synthesizes representative literature on a topic in an integrated way. Most integrative reviews may require the author to adopt a guiding theory, a set of competing models, or a point of view about a topic. For more description of integrative reviews, see Whittemore & Knafl (2005) [https://edtechbooks.org/-EaoJ] .

Examples of an Integrative Review:

Exploring the gap between teacher certification and permanent employment in Ontario: An integrative literature review ( Brock & Ryan, 2016 [https://edtechbooks.org/-EaoJ] ).
Meta-analysis

A subset of a systematic review, a meta-analysis takes findings from several studies on the same subject and analyzes them using standardized statistical procedures to pool together data. As such, it integrates findings from a large body of quantitative findings to enhance understanding, draw conclusions, and detect patterns and relationships. By gathering data from many different, independent studies that look at the same research question and assess similar outcome measures, data can be combined and re-analyzed, providing greater statistical power than any single study alone. It’s important to note that not every systematic review includes a meta-analysis but a meta-analysis can’t exist without a systematic review of the literature.

Examples of a Meta-Analysis:

Efficacy of the cooperative learning method on mathematics achievement and attitude: A meta-analysis research ( Capar & Tarim, 2015 [https://edtechbooks.org/-EaoJ] ).
Gender differences in student attitudes toward science: A meta-analysis of the literature from 1970 to 1991 ( Weinburgh, 1995 [https://edtechbooks.org/-EaoJ] ).

Narrative/Traditional

A narrative or traditional review provides an overview of research on a particular topic that critiques and summarizes a body of literature. Typically broad in focus, these reviews select and synthesize relevant past research into a coherent discussion. Methodologies, findings and limits of the existing body of knowledge are discussed in narrative form. This requires a sufficiently focused research question, and the process may be subject to bias that supports the researcher’s own work.

Examples of a Narrative/Traditional Review:

Adventure education and Outward Bound: Out-of-class experiences that make a lasting difference ( Hattie, Marsh, Neill, & Richards, 1997 [https://edtechbooks.org/-EaoJ] ).
Good quality discussion is necessary but not sufficient in asynchronous tuition: A brief narrative review of the literature ( Fear & Erikson-Brown, 2014 [https://edtechbooks.org/-EaoJ] ).

This specific type of literature review is theory-driven and interpretative and is intended to explain the outcomes of a complex intervention program(s).

Examples of a Realist Review:

Unravelling quality culture in higher education: A realist review ( Bendermacher, Egbrink, Wolfhagen, & Dolmans, 2017 [https://edtechbooks.org/-EaoJ] ).

This type of review tends to be a non-systematic approach that focuses on breadth of coverage rather than depth. It utilizes a wide range of materials and may not evaluate the quality of the studies as much as count the number. Thus, it aims to identify the nature and extent of research in an area by providing a preliminary assessment of size and scope of available research and may also include research in progress.

Examples of a Scoping Review:

Interdisciplinary doctoral research supervision: A scoping review ( Vanstone, Hibbert, Kinsella, McKenzie, Pitman, & Lingard, 2013 [https://edtechbooks.org/-EaoJ] ).

In contrast to an exploratory review, the purpose of a synoptic review is to provide a concise but accurate overview of all material that appears to be relevant to a chosen topic. Both content and methodological material is included. The review should aim to be both descriptive and evaluative as it summarizes previous studies while also showing how the body of literature could be extended and improved in terms of content and method by identifying gaps.

Examples of a Synoptic Review:

Theoretical framework for educational assessment: A synoptic review ( Ghaicha, 2016 [https://edtechbooks.org/-EaoJ] ).
School effects research: A synoptic review of past efforts and some suggestions for the future ( Cuttance, 1981 [https://edtechbooks.org/-EaoJ] ).

Systematic Review

A rigorous review that follows a strict methodology designed with a presupposed selection of literature reviewed, systematic reviews are undertaken to clarify the state of existing research, evidence, and possible implications that can be drawn. Using comprehensive and exhaustive searching of the published and unpublished literature, searching various databases, reports, and grey literature, these reviews seek to produce transparent and reproducible results that report details of time frame and methods to minimize bias. Generally, these reviews must include teams of at least 2-3 to allow for the critical appraisal of the literature. For more description of systematic reviews, including links to protocols, checklists, workflow processes, and structure see “ A Young Researcher’s Guide to a Systematic Review [https://edtechbooks.org/-oF] “.

Examples of a Systematic Review:

The potentials of using cloud computing in schools: A systematic literature review ( Hartmann, Braae, Pedersen, & Khalid, 2017 [https://edtechbooks.org/-EaoJ] ).
The use of research to improve professional practice: a systematic review of the literature ( Hemsley-Brown & Sharp, 2003 [https://edtechbooks.org/-EaoJ] ).

Umbrella/Overview of Reviews

An umbrella review compiles evidence from multiple systematic reviews into one document. It therefore focuses on broad conditions or problems for which there are competing interventions and highlights reviews that address those interventions and their effects, thereby allowing for recommendations for practice. For a brief discussion see “ Not all literature reviews are the same [https://edtechbooks.org/-xZ] ” (Thomson, 2013).

Examples of an Umbrella/Overview Review:

Reflective practice in healthcare education: An umbrella review ( Fragknos, 2016 [https://edtechbooks.org/-EaoJ] ).

Why do a Literature Review?

The purpose of the literature review is the same regardless of the topic or research method. It tests your own research question against what is already known about the subject.

First – It’s part of the whole.

Omission of a literature review chapter or section in a graduate-level project represents a serious void or absence of a critical element in the research process.

The outcome of your review is expected to demonstrate that you:

can systematically explore the research in your topic area
can read and critically analyze the literature in your discipline and then use it appropriately to advance your own work
have sufficient knowledge in the topic to undertake further investigation

Second – It’s good for you!

You improve your skills as a researcher
You become familiar with the discourse of your discipline and learn how to be a scholar in your field
You learn through writing your ideas and finding your voice in your subject area
You define, redefine and clarify your research question for yourself in the process

Third – It’s good for your reader.

Your reader expects you to have done the hard work of gathering, evaluating, and synthesizing the literature. When you do a literature review you:

Set the context for the topic and present its significance
Identify what’s important to know about your topic – including individual material, prior research, publications, organizations and authors.
Demonstrate relationships among prior research
Establish limitations of existing knowledge
Analyze trends in the topic’s treatment and gaps in the literature

So, why should you do a literature review?

To locate gaps in the literature of your discipline
To avoid reinventing the wheel
To carry on where others have already been
To identify other people working in the same field
To increase your breadth of knowledge in your subject area
To find the seminal works in your field
To provide intellectual context for your own work
To acknowledge opposing viewpoints
To put your work in perspective
To demonstrate you can discover and retrieve previous work in the area

Common Literature Review Errors

As you begin your own graduate-level literature review, try to avoid these common mistakes:

Accepting another researcher’s finding as valid without evaluating methodology and data
Ignoring contrary findings and alternative interpretations
Providing findings that are not clearly related to one’s own study or that are too general
Allowing insufficient time to defining best search strategies and writing
Reporting rather than synthesizing isolated statistical results
Choosing problematic or irrelevant keywords, subject headings and descriptors
Relying too heavily on secondary sources
Failing to transparently report search methods
Summarizing rather than synthesizing articles

In conclusion, the purpose of a literature review is three-fold:

to survey the current state of knowledge or evidence in the area of inquiry,
to identify key authors, articles, theories, and findings in that area, and
to identify gaps in knowledge in that research area.

Literature reviews should be reasonably complete and not restricted to a few journals, a few years, or a specific methodology or research design. Reviewed articles may be summarized in the form of tables and can be further structured using organizing frameworks such as a concept matrix.

Test Yourself

The purpose of a graduate-level literature review is to summarize in as many words as possible everything that is known about my topic.

Read the following abstract and choose the correct type of literature review it represents.

The focus of this paper centers around timing associated with early childhood education programs and interventions using meta-analytic methods. At any given assessment age, a child’s current age equals starting age, plus duration of program, plus years since program ended. Variability in assessment ages across the studies should enable everyone to identify the separate effects of all three time-related components. The project is a meta-analysis of evaluation studies of early childhood education programs conducted in the United States and its territories between 1960 and 2007. The population of interest is children enrolled in early childhood education programs between the ages of 0 and 5 and their control-group counterparts. Since the data come from a meta-analysis, the population for this study is drawn from many different studies with diverse samples. Given the preliminary nature of their analysis, the authors cannot offer conclusions at this point. ( Duncan, Leak, Li, Magnuson, Schindler, & Yoshikawa, 2011 [https://edtechbooks.org/-EaoJ] ).

In this review, Mary Vorsino writes that she is interested in keeping the potential influences of women pragmatists of Dewey’s day in mind while presenting modern feminist re readings of Dewey. She wishes to construct a narrowly-focused and succinct literature review of thinkers who have donned a feminist lens to analyze Dewey’s approaches to education, learning, and democracy and to employ Dewey’s works in theorizing on gender and education and on gender in society. This article first explores Dewey as both an ally and a problematic figure in feminist literature and then investigates the broader sphere of feminist pragmatism and two central themes within it: (1) valuing diversity, and diverse experiences; and (2) problematizing fixed truths. ( Vorsino, 2015 [https://edtechbooks.org/-EaoJ] ).

Linda Frederiksen is the Head of Access Services at Washington State University Vancouver. She has a Master of Library Science degree from Emporia State University in Kansas. Linda is active in local, regional and national organizations, projects and initiatives advancing open educational resources and equitable access to information.

Sue F. Phelps is the Health Sciences and Outreach Services Librarian at Washington State University Vancouver. Her research interests include information literacy, accessibility of learning materials for students who use adaptive technology, diversity and equity in higher education, and evidence based practice in the health sciences

Brigham Young University

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Undertaking a literature review: a step-by-step approach

Affiliation.

1 School of Nursing and Midwifery, University of Dublin,Trinity College, Dublin.
PMID: 18399395
DOI: 10.12968/bjon.2008.17.1.28059

Nowadays, most nurses, pre- and post-qualification, will be required to undertake a literature review at some point, either as part of a course of study, as a key step in the research process, or as part of clinical practice development or policy. For student nurses and novice researchers it is often seen as a difficult undertaking. It demands a complex range of skills, such as learning how to define topics for exploration, acquiring skills of literature searching and retrieval, developing the ability to analyse and synthesize data as well as becoming adept at writing and reporting, often within a limited time scale. The purpose of this article is to present a step-by-step guide to facilitate understanding by presenting the critical elements of the literature review process. While reference is made to different types of literature reviews, the focus is on the traditional or narrative review that is undertaken, usually either as an academic assignment or part of the research process.

Publication types

Choice Behavior
Data Collection / methods*
Data Interpretation, Statistical*
Databases, Bibliographic
Evidence-Based Medicine
Information Storage and Retrieval
Meta-Analysis as Topic
Nursing Research / education
Nursing Research / organization & administration*
Professional Competence
Research Design*
Review Literature as Topic*

Literature Reviews for Education and Nursing Graduate Students

(13 reviews)

Linda Frederiksen, Washington State University Vancouver

Sue F. Phelps, Washington State University Vancouver

Publisher: Rebus Community

Language: English

Formats Available

Conditions of use.

Learn more about reviews.

Reviewed by Yolanda Griffiths, Professor of Occupational Therapy, Drake University on 12/15/21

Comprehensiveness rating: 5 see less

The authors were thorough and very organized in stepping readers through the process of conducting and writing a literature review. Each area is appropriately indexed and examples are provided in a variety of ways. The synthesis section is especially useful as students often do not understand what this means. Perhaps some content on plagiarism would benefit this section as well. The flow of the material easily guides users logically through each topic.

Content Accuracy rating: 5

The content is accurate and unbiased. The content is presented in an easy to understand way with videos, and examples.

Relevance/Longevity rating: 5

The relevance of the content is classic and the text should be pertinent for many years. The links included in the text are very useful and should be easy for authors to check periodically. Using a digital media is more relevant to today's students than print textbooks. Each section addresses a reasonable chunk of information.

Clarity rating: 5

The book is user friendly, written in an easy to understand manner, and graphics or links add to the understanding of the content. Definitions are clearly written. Such as clarifying the types of literature reviews will be useful for students. Providing a test yourself section at the end of sections allows the reader to check if any content was confusing or not clear.

Consistency rating: 5

The text is consistently laid out in a logical manner which helps to unpack content which may be new or unfamiliar to the reader/student.

Modularity rating: 5

The amount of content allocated to each chapter is appropriate and will be easy to assign readings. The chapter headings are clear and the embedded videos, charts and test questions enlighten each subunit. The hyperlinking in the table of contents helps to navigate the chapters well.

Organization/Structure/Flow rating: 5

The organization of the content is logical and easy to understand the process of completing a literature review. The book is laid out much like a road map where students can see the big picture as well as the supporting parts to the process. The references by chapter are very useful.

Interface rating: 5

The graphics were clear, and the non-serif font aids in eye fatigue. One recommendation is to lower the brightness of the bold blue text in the table of contents to reduce eye fatigue. There was no problem to play the videos and the audio was clear. All links worked well.

Grammatical Errors rating: 5

There were no grammatical errors. There were a few typos such as 1.3.1.8 needs a space between "A specific", 2.3 in the phrase "Articles by the type of periodical in which an article it is published" perhaps remove the word "it", in the table on page 41. under Nursing , the word clinical is spelled "Cclinical", remove the capital C.

Cultural Relevance rating: 5

No evidence of cultural bias or insensitivity.

I am very excited to use this textbook in my doctoral level occupational therapy class. The inclusion of concise explanations of PICO and SPICE will be very useful. This will be a wonderful resource for graduate students and being mindful of costs for textbooks is compassionate.

Reviewed by Susan Bassett, Instructor, Nursing Graduate Program, Eastern New Mexico University on 11/9/21

Each chapter presented a different aspect of doing a literature review. This was organized and orderly. The index/table of contents was very detailed which allowed the reader to easily use this book as a reference while conducting a literature... read more

The content appeared to be entirely accurate. It did a good job of combining information for both education and nursing students. The authors addressed pertinent points of research study development as well as the specific methodology of approaching a research-focused literature review.

The text was up-to-date in methodology, which should not change frequently. The many links to websites were very helpful and yet were basic enough that they should be relevant for years. If they do need updating, the are clearly presented and should be easily updated. The breakdown to very small "chunks" of information per section will help in easily updating specific parts of information.

The book presented a rather complex topic in an extremely straight-forward, easy to read, clear manner. Each small "chunk" of information was identified per section numbering which correlated with movement through the content. The writing was professional and yet not overwhelmed with discipline-specific terminology. Where potentially new terminology was presented, it was immediately followed with definitions and examples.

The book was well-organized and moved along the structure set out early in the book. Content was gradually unfolded, as divided per chapter. There was a bit of repetition (probably about three examples) where the authors attempted to tie information together. Although this stood out to a reader, it seemed more useful in organizing than detrimental in repetition.

The book was subdivided into chapters and then into many small modules of discrete information. It could easily be assigned in part. It could also readily be used as a reference for students to go back and easily find processes or pieces of information they might need later.

I found the continual clear and succinct organization of information to be a defining highlight of this book. When presenting early steps of the research process and then linking these steps with how to conduct a literature review and subsequenty organize and write a literature review, this book is presenting numerous procews steps that must work in tandem. This book did that in a clear and easily readable fashion.

The one feature that did distract me was within the bullet points of 1.3.1. "Types of Reviews". There was a mix of complete and incomplete sentences that worked to convey information succinctly, but distracted me as a reader.

Grammatical Errors rating: 4

I did find several spelling and grammaticl errors (1.3.1.8, , 1.3.1.9, 2.1.1, 2.3, 2.3.1.1, , 2.3.1.4, 2.3 Table A., p. 41, p. 53, p. 54). Although small errors (a few letters or spacing) they should be corrected.

I did not find any mistakes in cultural appropriateness The content did repeatedly talk about bias reduction in the process of writing a literature review

I thought this book was very well-written and contained great information for my students. The links provided were very appropriate and helpful. The Table "Guide to searching for literature at various stages of the scholarly communication process” was particularly helpful. I will immediately begin using portions of the content in this book to support my research class. Additionally, I will recommend the entire book as a reference for the dedicated student (or one intending to go forward to a doctoral level of education in nursing). Thank you for collating all this information and helpful links into one clear, easily readable and understandable document.

Reviewed by Leah Nillas, Associate Professor, Illinois Wesleyan University on 9/6/21

Comprehensiveness rating: 4 see less

This book addresses the basic steps in the process of writing a literature review research. Chapter 2 (What is a Literature Review?) needs to be retitled. I think Chapter 1 (Introduction) clearly defines and characterizes literature review as a research category. Chapter 2 focuses more on the creation of information, information cycle, and selecting appropriate sources. Chapter 7 (Synthesizing Sources) and Chapter 8 (Writing the Lit Review) can still be improved to incorporate specific strategies in synthesizing research literature and examples of writing styles through analysis of a variety of published examples. Writing a synthesis is a challenging skill for most novice researchers.

Information shared is accurate. I did not notice any content error.

Relevance/Longevity rating: 4

Main content is up-to-date. A few citations maybe dated but they are necessary in illustrating different examples of literature reviews. It will be easy to include additional relevant examples of research work that are published recently.

I like how this text is written. Tone is reader friendly and narrative is accessible to novice researchers.

Clearly consistent throughout the chapters.

Clear and purposeful "chunking" of information per chapter.

Readers can easily follow the organization of topics and content.

No obvious interface issues. Appropriate use of multimedia tools.

No grammatical errors.

Text is culturally sensitive. Additional readings, references, or examples can easily be added to incorporate research conducted by diverse authors or literature reviews which focus on diversity and inclusion issues in education and nursing.

This is a good introductory literature review text even for undergraduate education students. Clear discussion of the nature of the research and the writing process. The use of videos and images is helpful in providing multimodal approach in explaining topics or processes. Writing style and tone make the text accessible to novice researchers.

Reviewed by Rebecca Scheckler, Assistant Professor, Radford University on 7/6/20

Two missing topics were inter-library loan and how to avoid plagiarism in writing up the literature review. This second is such an important topic that it deserves its own chapter. read more

Two missing topics were inter-library loan and how to avoid plagiarism in writing up the literature review. This second is such an important topic that it deserves its own chapter.

It is accurate. I found no inaccuracies.

This book is very relevant. Every advanced undergraduate or graduate students requires such a book

I found the book clear. The videos interspersed within the book added much to the clarity. There are lots of good diagrams that add to the clarity. They are not all original but their sources are all cited. The section on boolean searches, usage of asterisks and quotes in searches is very helpful and appropriate although often left out of discussion of searches.

The book is consistent in terminology and framework.

The chapters were cohesive.

Organization/Structure/Flow rating: 4

I like the links to within the text to the references and other matter. What is needed are back links to the text from the references. I also would have liked links from the exercises to the answers of the exercises.

Interface rating: 4

See navigation links mentioned above. The grey literature link is broken.

I saw no grammatical problems. There are many bulleted lists rather than text which is appropriate to this topic.

There could be more attention to cultural context in the frequent examples.

I wondered why nursing and education were combined. They are similar in nature but not identical. separation them out into two books might be appropriate.

Reviewed by Lisa Shooman, Associate Professor, Worcester State University on 6/29/20

Overall, this book provides a very comprehensive and thorough roadmap for creating a literature review. The videos assist the reader in crystallizing the information presented in the text. There is an effective index and glossary that provide... read more

The content is detailed, clearly explained, error-free, and unbiased. My students would greatly benefit from the lucid information presented in this text to guide them with developing a literature review. I would be eager to adopt this book for my students.

The content is timely and will not be quickly out-of-date. The quiz questions at the end of each chapter are relevant and will aid students with the consolidation of the material. The online format allows for updating, and the version history at the end of the text clearly indicated that the book was updated recently.

The text is clear and not ridden with any excess jargon /technical terminology. Pictures, graphics, and videos further elucidate the text. There are helpful questions that stimulate thought and lists that help to organize information.

The internal consistency in the text is excellent. However, Chapter 1.1 and Chapter 2 have the same title and it would benefit the reader to have different titles that would highlight the differences between these two sections. Chapter 1.1 is an overview and Chapter 2 dives into more depth.

The text is efficiently divided into smaller reading sections that are demarcated by numbers. The subsections in each chapter can be assigned at different points in the course. The text is organized logically and systematically that assists the reader with comprehension and provides a roadmap for creating an effective literature review.

The entire text is presented coherently and concisely. The organization of the text takes the reader through the process of creating an effective literature review. It can be used by multiple health professions, although the length of the text is relatively short it includes a considerable depth of the material. Other disciplines that would benefit from using this test in their courses may include occupational therapy, physical therapy, and speech and language pathology students.

The interface of the text is simple and easy to follow. The cover of the text would benefit from photos, color, and graphic design to appeal to the modern digital reader.

No grammatical or spelling errors are noted.

No cultural biases existed in the text in any way. There are no individuals highlighted in the book, and due to the technical nature of the subject matter, the text is inclusive to a variety of races, ethnicities, and backgrounds. No offensive statements are included in this book.

The authors should consider including other health professionals in the title and provide examples that can relate to other health professionals throughout the text. Other health professionals that can benefit from reading this text include occupational therapy, physical therapy, and speech and language pathology students. Literature reviews are relevant for many health professionals in their master's and doctorate programs and the text could serve a wider audience.

Reviewed by Ellen Rearick, Assistant Professor, Framingham State University on 6/1/20

This text covers all areas and the process of the integrative review appropriately. It is an engaging text for graduate students new to these assignments. read more

This text covers all areas and the process of the integrative review appropriately. It is an engaging text for graduate students new to these assignments.

This text is well done, very accurate

This text is relevant. The updates needed regarding APA format should be relatively easy to implement.

This text is clear and provides users with definitions and examples of the variety of reviews.

Very well written using consistent terminology throughout.

The text's reading sections are easily accessible and users will find them organized. Each chapter and its sections are presented in the sequence of the process of an integrative review.

Very clear and logical order.

The navigation of this text was problem-free.

No grammatical errors noted.

No issues with cultural insensitivity noted.

This was a well-organized text using videos to reinforce content that would benefit any education or nursing graduate student new to the integrative review process.

Reviewed by Ruth Stoltzfus, Professor of Nursing; Dir., Grad Programs in Nursing, Goshen College on 6/1/19

This text provides everything a graduate student needs to write a literature review in a concise manner. If you look at the digital pdf, there are many strategies to help the reader learn the process - videos, diagrams, and also text. read more

I found no evidence of bias and no errors.

This book has long-term relevance. The content will not quickly out-date.

I really liked the way the textbook is structured. The author is concise which makes the textbook easy to read.

I found no inconsistencies in terminology or other aspects related to the content.

I will adopt this text for a research course I use and will likely assign only specific chapters. I plan to recommend the textbook to another faculty who teaches a comprehensive research course with the idea of assigning only specific sections to read..

The textbook begins with an introduction to the subject matter. Subsequent chapters develop specific aspects related to lit reviews. The textbook provides a nice "how to" for each element of a lit review. Chapters are also organized in a smooth, easy to follow format.

I only looked at the digital pdf and print pdf versions. The print pdf indicates that there are videos to watch, but of course since it is a print pdf, there is no linkage. I think this would be obvious to a savvy reader - that a print pdf will be limited in what the reader can access.

I found no grammatical errors in my quick read.

I found no evidence of cultural bias or insensitivity.

This is the first open textbook that I have encountered. I was expecting it to be flat and boring! However, it was neither of those. There were color diagrams, color photos, and even videos embedded in the textbook.

I have adopted this book for the Research Lit Review course that I am teaching soon. I am impressed!

Reviewed by Melissa Wells, Assistant Professor, University of Mary Washington on 5/1/19

This book helps students in education and nursing complete a literature review, which may be the first time these students are tackling such a task. The chapters break down the process into defining the special genre of a literature review; providing tips to get started; suggesting where students can find literature to review; explaining how to evaluate sources; detailing the process of documenting sources; giving advice for synthesizing sources; and finally, putting all of these pieces together into a final literature review. Most significantly, the text provides specific examples of ideas presented in the context of both nursing and education, which makes the content directly relatable to the student's course of study. The conclusion recaps the main points of each chapter in bullet form. The text is lacking both an index and a glossary, which would be additions that could strengthen the text.

Content Accuracy rating: 4

The text explains 11 different types of literature reviews that students may encounter or be asked to create. Also, the text is framed to work with multiple methodologies; for example, steps for writing a research question or a hypothesis to frame the literature review are provided. One inconsistency I noted was in diagram 6.2: the APA citation is incorrectly capitalized for the journal title (which should use sentence, not title, capitalization).

The text also includes external links to sources, such as a videos, which provide students with multiple modalities in which to digest the information. An example of a literature review for both education and nursing is provided at the end of the book; instead of embedding these in the text, the hyperlinks refer the reader to the external site. This will be easy to change to a new example in the future, but checks will need to be done to ensure that all such external sources remain actively accessible.

Each chapter opens with learning objectives to help frame the content with which the reader is about to engage. Throughout the text, the language is approachable and reader-friendly. For example, when the text explains more factual components (i.e., what makes a literature review or what the basics of an effective literature review include), this information is presented in bullet points with hyperlinks to the original sources.

Each chapter follows a similar construction, which makes it accessible to the reader. For example, chapters end with a "Practice" and "Check Yourself" section to apply new learning and self-check responses (an answer key is provided in an appendix). Examples in these exercises are either related to nursing or education, continuing with the stated theme of the text.

When I used this text with my own students, I assigned chapters in isolation, since they had already taken a research methods course and were applying that knowledge to create a research proposal in a specific area of study in my course.

The book is organized in such a way that logically walks the reader through the literature review writing process. Clear headings (which are hyperlinked in the table of contents) also allow the reader to jump to specific parts with which they need additional support.

The interface of this document offered a lot of flexibility. Options allowed users to access the text online, or as a download in multiple file types (EPUB, Digital PDF, MOBI, XHTML, Pressbooks XML, Wordpress XML, and Open Document). These formats provide the reader with an opportunity to pick the interface that works best for them.

I did not see any grammatical errors in the text.

Cultural Relevance rating: 4

No culturally insensitive/offensive content was noted. A variety of examples of research topics were included from both nursing and education. Of the images/video thumbnails embedded in the text that involved people, all depicted White people except for 2 images; therefore, more intentional selection of culturally diverse visuals would be helpful in future versions of this text.

I feel this text was helpful to my students as they wrote their own literature reviews. The only weakness in their papers that I noted was their organization of their literature review based on themes/topic, which was addressed in Chapters 7- 8. I now know to focus more on this part of literature review writing with future students. This text is approachable and field-specific, and I will be using it again!

Reviewed by Bernita (Bernie) Missal, Professor, Bethel University on 12/14/18

This book includes all areas that a graduate student needs to begin a literature review. However metasynthesis could have also been included in types of literature review. read more

This book includes all areas that a graduate student needs to begin a literature review. However metasynthesis could have also been included in types of literature review.

This book is accurate although missing qualitative research.

Although content is up to date, some of the article examples need to be updated. (Example: articles published in 1981 and 1992 need to be updated to more recent articles.)

The book is clear and easy to follow. Bullet points were used throughout the book with short paragraphs which helps the student.

Each chapter follows the same format with narrative followed by practice and test questions.

Clear subheadings are used throughout the book.

This book is presented in a logical way and easy for the student to follow.

Images are clear and appropriate for the content.

No specific grammar issues were seen.

It would be helpful for students to include additional examples of cultural studies throughout the book

This book is an excellent resource for graduate students. It has helpful information for the preparation and process for a literature review. Examples of written literature reviews in chapter 8 or in an appendix would be helpful for students.

Reviewed by Nancyruth Leibold, Associate Professor, Southwest Minnesota State University on 6/19/18

The text is overall comprehensive, yet it breaks the information up into manageable parts. See the table of contents for an overview of the topics. The text is very quantitative driven in that the focus is on reviewing quantitative studies. The book included information about PICO statements, but did not include PICO(T) or the time variable, which is not always used in every case. Population was included in the PICO explanation, but a bit more information on the population or aggregate narrowing could improve the PICO section. These items do not hinder use of the book, but these items would need further inclusion by the faculty member using the text as specific to the discipline.

The content in the book is very accurate.

The content in the book is current and should not be obsolete within a short period of time. Any updates would be easy to add.

The text is clear and easy to understand.

The internal organization and terminology of the book is consistent and logical

The text is set up in small reading sessions. The videos and learning activities are well done and break up some of the content, so there is a variety of presentation. The tutorials, figures, practice and self-test areas are also fantastic in that they are quality and sprinkled throughout the text.

The topics in the book are presented in clear and organized fashion. I particularly like the upbeat and personal writing tone of the book. This tone makes it seem like the authors are speaking to me.

The text is free of any significant interface issues. The book is available in many formats. I used the book online and I did have one navigational problem and that is when clicking on a video, it does not open in a new tab and so the book is lost and have to start over going in the start to the book. One easy solution to this is to right click your mouse and then select open in new tab to watch videos. That way, your place in the book is not lost.

No grammar problems present.

The book is not culturally insensitive or offensive in any way.

Overall, this is a well written textbook and I recommend it!

Reviewed by Marjorie Webb, Professor, Metropolitan State University on 6/19/18

From the Introduction to the Conclusion, the text covers the step-by-step process of conducting a literature review. The text includes topics such as, “Where to find the Literature” and “Synthesizing Sources” that will be useful to graduate... read more

The content in the text, including texts, links, and diagrams, is accurate and unbiased. Again, it will aid the graduate nursing student in the long process of conducting a literature review.

The text is current and this type of material does not become dated quickly. The authors did use internet links in the text which will need to be monitored periodically to ensure they are still available. Updates to the text will be relatively easy and straightforward. If media styles change, there may be some challenges to updating.

The text is clear and easy to read. Technical terminology is defined and/or explained.

The text is internally consistent.

The text is organized in sections which facilitates assigning readings based on the subject matter for the class time. It would be pretty easy to divide up this text into easily readable units based on headings and subheadings.

This text is structured well. The topics flow in an organized manner and really help the student see the process of a literature review. The authors discuss the both theory and purpose of the review and the day-to-day logistics of actually performing the review. The day-today organization is not always included in other texts.

The interface is well-done with no distractions.

There was no indication of cultural bias.

I think this text is appropriate for graduate nursing students. Some students struggle with the difference between writing about a topic (generally undergraduate writing) and synthesizing literature on a given topic (generally graduate writing). Chapters seven and eight focus on preparing the graduate student to make the jump to graduate-level writing and should really benefit new graduate students.

Reviewed by Susanna Thornhill, Associate Professor , George Fox University on 3/27/18

This book is fairly comprehensive and offers step-by-step instructions for conceptualizing/researching a literature review. The Table of Contents is well-organized to reflect the book's progression, from establishing the basics of why to write a literature review and the various types of literature reviews, to getting started with formulating a research idea/question, finding and evaluating sources, synthesizing sources, and guidelines on writing the literature review, itself. I found this text to be a straightforward guide for my graduate students in education, and while I worried at first that the merging of education and nursing topics would prove distracting to my education students, I don't believe this was the case.

One thing that was not comprehensive in this book was discussion of qualitative research and methodologies as a valid means of conceptualizing research aims. I hoped for a more balanced discussion between methodological branches as it applied to literature reviews; this book overly favored quantitative methodologies and studies in terms of its direction to readers about how to conceptualize/choose a topic and design a research question in relation to it. Variables that cannot be measured are not inherently un-researchable, which is the conclusion put forth in this textbook. This might serve nursing students better than education students in terms of their discipline's requirements, but it still represents an element that could be improved.

Finally, while the background on what a literature review is, how to conceptualize research, and how to search for and synthesize research was all valuable, the chapter on actually writing the literature review was a bit thin, simply offering tips for introduction, body, and conclusion and some questions for self-evaluation. Some of the most difficult work for students writing a literature review is achieving proper focus, organization, hierarchy of themes, balance in treatment of related topics, etc. None of these issues were discussed in the chapter pertaining to the writing of a literature review.

I did not have any concerns about the book's accuracy. Content was accurate, albeit biased to quantitative and positivist views of research. I would have liked to see it include additional prompts to support students in conceptualizing and valuing qualitative research; this is an area where I had to supplement course readings with additional texts.

The only significant error I could discern in the text was a lack of an Answer Key corresponding to the questions posed at the end of each chapter.

Content is up-to-date and seems like it will hold meaning well over the next few years. The only things I anticipate might go out-of-date is technological information on things like citation managers, search guidelines, and database information. This is easily updatable with future versions of the text. In my view, ERIC is not the best database for educational research and I have confirmed this with educational librarians who support my students, yet it is the only one identified in this text as the best subject-specific source of educational research; this could be revised for additional relevance.

I noticed no issues with the book's clarity. The authors write in a clear and straightforward style, making the text easy to read. Overall, they did well writing for students across two disciplines by avoiding nursing or education-specific terms that would have been problematic to readers in the other discipline.

The book is internally consistent and did not have issues with terminology or framework.

No issues with the book's modularity. Chapter headings and sub-headings were appropriately paced and spaced. I assigned this textbook to my graduate students as a whole text that I wanted them to read at the beginning of a course, but it has been easy to refer them back to particular topics as the course has continued.

In future iterations of the book, I suggest hyperlinking the Answer Key to the exercises at the end of each chapter and/or listing the Answer Key in the Table of Contents for easy referral.

I found the book's organization to be straightforward and sensible. The Table of Contents offers a helpful snapshot of the scope of the book and the authors write in a direct and clear style, which contributes to an appropriate flow for the text.

I did not note any navigation problems with any links. All charts/images loaded well in my iBook app. The authors did a nice job of pulling relevant content and links in to support their ideas; it provided an easy way to seek more information if I wanted it, without feeling like the text was loaded down with unnecessary information.

I only found a few small typos in the text, with no grammar issues. The book is obviously written by two very detail-oriented librarians. I appreciated the clarity of the text and lack of errors.

The text was not culturally insensitive; a variety of topics across nursing and education were discussed as examples, which yielded a fairly balanced text regarding cultural considerations.

Reviewed by Alicia Rossiter, Assistant Professor, University of South Florida on 3/27/18

I believe the book gives a comprehensive overview on how to complete a literature view at the graduate level. It begins with an overview of the purpose of a literature review and moves through the steps to completing the review process. read more

I believe the book was accurate and unbiased. It was easy to read but comprehensive.

Content within the text is relevant and supports the literature view process. It did discuss the various databases for searches which may need updating to include new sites, search engines but otherwise relevant and useful information.

The text is easy to read, provides appropriate examples, includes a section on putting the process into practice as well as a "test yourself" section to ensure the content is understood.

The text is consistent throughout in regards to terminology, framework, and set up.

The text is easy to read and content is leveled for the reader but not over simplified. Content is chunked into sections making it easy for the reader to digest the content. The chapters are well laid out and flow from chapter to chapter. Each chapter contains learning objectives, content sections, practice section, and test yourself section. Well organized and great visuals.

Topics are presented in a logical, clear fashion that flow from chapter to chapter and build as the reader moves through the process.

The text is free of interface issues. I could not get the videos to play but other visuals were appropriate and useful to support content.

The text contains no grammatical errors.

The text is not culturally offensive. There was no evidence of bias or cultural insensitivity.

I think this would be a great resource for graduate student learning to navigate the literature review process. It is easy to read, straightforward, and guides the individual through the process from start to finish. I will recommend this text to my graduate students in evidence-based practice and research courses as a recommended reference.

Chapter 1: Introduction
Chapter 2: What is a Literature Review?
Chapter 3: How to Get Started
Chapter 4: Where to Find the Literature
Chapter 5: Evaluating Sources
Chapter 6: Documenting Sources
Chapter 7: Synthesizing Sources
Chapter 8: Writing the Literature Review

Ancillary Material

About the book.

Literature Reviews for Education and Nursing Graduate Students is an open textbook designed for students in graduate-level nursing and education programs. Its intent is to recognize the significant role the literature review plays in the research process and to prepare students for the work that goes into writing one. Developed for new graduate students and novice researchers just entering into the work of a chosen discipline, each of the eight chapters covers a component of the literature review process. Students will learn how to form a research question, search existing literature, synthesize results and write the review. The book contains examples, checklists, supplementary materials, and additional resources. Literature Reviews for Education and Nursing Graduate Students is written by two librarians with expertise guiding students through research and writing assignments, and is openly licensed.

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Literature Review

What is a literature review.

Students are often unsure of how to write a literature review. This is usually because, unlike other stages of a thesis such as Methods and Results, they have never written a literature review before.

FAQs about literature reviews

In the table below, you will find some of the questions that students ask, and some suggested answers.

Examples of literature reviews: organisation

Here you will find some examples from past Honours theses. The first set of examples shows part of the Table of Contents, so that you can see the kind of information included in a literature review. What can you notice about how the students have organised their reviews?

From the School of Biotechnology and Biomolecular Sciences

1. INTRODUCTION ............................................... 1

1.1 HEPATITIS C VIRUS................................. 1

1.1.1 Genome ................................................ 1 1.1.2 Pathogenesis.......................................... 2 1.1.3 Transmission.......................................... 3 1.1.4 Epidemiology.......................................... 5 1.1.5 Treatment.............................................. 5

1.2 QUASISPECIES............................................ 7

1.2.1 Quasispecies and Treatment Outcome....... 7

1.3 METHODS TO ANLAYSE QUASISPECIES........... 8

1.3.1 Cloning and Sequencing........................... 9 1.3.2 Heteroduplex Mobility Analysis (HMA)........ 9 1.3.3 Capillary Electrophoresis......................... 11

1.4 HYPOTHESIS AND AIMS ............................... 11

(Oon 2005, p.ii)

What organisational approach has the student taken in example A?

From the School of Photovoltaic and Renewable Energy Engineering

2. LITERATURE REVIEW .......................................... 2-1

2.1 CLASSIC DIFFUSION CONCEPT....................... 2-1

2.1.1diffusion mechanisms................................ 2-1 2.1.2 Fick’s law .................................................. 2-4

2.2 BORON DIFFUSION ........................................ 2-9

2.2.1 diffusivity ................................................ 2-9 2.2.2 segregation coefficient ............................. 2-10 2.2.3 silicon self-interstitial and diffusion rate....... 2-12 2.2.4 formation of boron rich layer (brl).............. 2-12 2.2.5 boron diffusion systems............................. 2-14

2.3 BORON NITRIDE SOLID SOURCE DIFFUSION..... 2-15

2.3.1 benefits and challenges.............................. 2-15 2.3.2 diffusion process........................................ 2-16

2.4 SOLAR CELL CHARACTERISATION..................... 2-18

What organisational approach has the student taken in example B?

Examples of literature reviews: language

Here you will find some more examples of literature reviews, showing how the students refer to and comment on previous research. Look at the following examples and see how the students summarise a number of studies and contrast differing findings. Also notice the use of evaluative language to show the student's evaluation of the previous research.

Summarising language
Contrast language
Evaluative language

"Several studies [5, 6, 7] have reported the benefits of using boron solid sources over other types of boron diffusion source. … On the contrary, Warabisako et al [9] demonstrated that obtaining high efficiencies with boron solid source was no easy task. They reported severe degradation of bulk minority carrier lifetime after boron solid source diffusion" (Chen, 2003, pp.2-14-2-15).

"On evaluation of the studies performed thus far, genotype 1b RdRp proteins have been studied extensively while RdRp proteins from other genotypes have been somewhat ignored. Kim et al. was the only group to have published a 3a RdRp paper, although their focus was on the template requirement for the NS5B gene as opposed to polymerase activity" (Tan, 2004, pp.15-16)

See next: Exercise for getting started on your literature review

Engineering & science.

Report writing
Technical writing
Writing lab reports
Introductions
Literature Review Exercise
Writing up results
Discussions
Conclusions
Writing tools
Case study report in (engineering)
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3.1 What is a literature review?

Learning objectives.

Describe the components of a literature review
Recognize commons errors in literature reviews

Pick up nearly any book on research methods and you will find a description of a literature review . At a basic level, the term implies a survey of factual or nonfiction books, articles, and other documents published on a particular subject. Definitions may be similar across the disciplines, with new types and definitions continuing to emerge. Generally speaking, a literature review is a:

“comprehensive background of the literature within the interested topic area” (O’Gorman & MacIntosh, 2015, p. 31).
“critical component of the research process that provides an in-depth analysis of recently published research findings in specifically identified areas of interest” (Houser, 2018, p. 109).
“written document that presents a logically argued case founded on a comprehensive understanding of the current state of knowledge about a topic of study” (Machi & McEvoy, 2012, p. 4).

Literature reviews are indispensable for academic research. “A substantive, thorough, sophisticated literature review is a precondition for doing substantive, thorough, sophisticated research…A researcher cannot perform significant research without first understanding the literature in the field” (Boote & Beile, 2005, p. 3). In the literature review, a researcher shows she is familiar with a body of knowledge and thereby establishes her credibility with a reader. The literature review shows how previous research is linked to the author’s project, summarizing and synthesizing what is known while identifying gaps in the knowledge base, facilitating theory development, closing areas where enough research already exists, and uncovering areas where more research is needed. (Webster & Watson, 2002, p. xiii). They are often necessary for real world social work practice. Grant proposals, advocacy briefs, and evidence-based practice rely on a review of the literature to accomplish practice goals.

A literature review is a compilation of the most significant previously published research on your topic. Unlike an annotated bibliography or a research paper you may have written in other classes, your literature review will outline, evaluate, and synthesize relevant research and relate those sources to your own research question. It is much more than a summary of all the related literature. A good literature review lays the foundation for the importance of the problem your research project addresses defines the main ideas in your research question and their interrelationships.

Literature review basics

All literature reviews, whether they focus on qualitative or quantitative data, will at some point:

Introduce the topic and define its key terms.
Establish the importance of the topic.
Provide an overview of the important literature on the concepts in the research question and other related concepts.
Identify gaps in the literature or controversies.
Point out consistent finding across studies.
Arrive at a synthesis that organizes what is known about a topic, rather than just summarizing.
Discusses possible implications and directions for future research.

There are many different types of literature reviews, including those that focus solely on methodology, those that are more conceptual, and those that are more exploratory. Regardless of the type of literature review or how many sources it contains, strong literature reviews have similar characteristics. Your literature review is, at its most fundamental level, an original work based on an extensive critical examination and synthesis of the relevant literature on a topic. As a study of the research on a particular topic, it is arranged by key themes or findings, which should lead up to or link to the research question.

A literature review is a mandatory part of any research project. It demonstrates that you can systematically explore the research in your topic area, read and analyze the literature on the topic, use it to inform your own work, and gather enough knowledge about the topic to conduct a research project. Literature reviews should be reasonably complete, and not restricted to a few journals, a few years, or a specific methodology or research design. A well-conducted literature review should indicate to you whether your initial research questions have already been addressed in the literature, whether there are newer or more interesting research questions available, and whether the original research questions should be modified or changed in light of findings of the literature review. The review can also provide some intuitions or potential answers to the questions of interest and/or help identify theories that have previously been used to address similar questions and may provide evidence to inform policy or decision-making (Bhattacherjee, 2012).

Literature reviews are also beneficial to you as a researcher and scholar in social work. By reading what others have argued and found in their work, you become familiar with how people talk about and understand your topic. You will also refine your writing skills and your understanding of the topic you have chosen. The literature review also impacts the question you want to answer. As you learn more about your topic, you will clarify and redefine the research question guiding your inquiry. Literature reviews make sure you are not “reinventing the wheel” by repeating a study done so many times before or making an obvious error that others have encountered. The contribution your research study will have depends on what others have found before you. Try to place the study you wish to do in the context of previous research and ask, “Is this contributing something new?” and “Am I addressing a gap in knowledge or controversy in the literature?”

In summary, you should conduct a literature review to:

Locate gaps in the literature of your discipline
Avoid “reinventing the wheel”
Carry on the unfinished work of other scholars
Identify other people working in the same field
Increase breadth and depth of knowledge in your subject area
Read the seminal works in your field
Provide intellectual context for your own work
Acknowledge opposing viewpoints
Put your work in perspective
Demonstrate you can find and understand previous work in the area

Common literature review errors

Literature reviews are more than a summary of the publications you find on a topic. As you have seen in this brief introduction, literature reviews are a very specific type of research, analysis, and writing. We will explore these topics more in the next chapters. As you begin your literature review, here are some common errors to avoid:

Accepting another researcher’s finding as valid without evaluating methodology and data
Ignoring contrary findings and alternative interpretations
Using findings that are not clearly related to your own study or using findings that are too general
Dedicating insufficient time to literature searching
Simply reporting isolated statistical results, rather than synthesizing the results
Relying too heavily on secondary sources
Overusing quotations from sources
Not justifying arguments using specific facts or theories from the literature

For a quick review of some of the pitfalls and challenges a new researcher faces when she begins work, see “ Get Ready: Academic Writing, General Pitfalls and (oh yes) Getting Started! ”.

Key Takeaways

Literature reviews are the first step in any research project, as they help you learn about the topic you chose to study.
You must do more than summarize sources for a literature review. You must have something to say about them and demonstrate you understand their content.
Literature review- a survey of factual or nonfiction books, articles, and other documents published on a particular subject

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Guidebook for Social Work Literature Reviews and Research Questions Copyright © 2020 by Rebecca Mauldin and Matthew DeCarlo is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

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Congratulations! You applied and were accepted into a graduate-level program at [fill in the blank] university. In your first research methods class, your assignment is to do a comprehensive literature review on a topic of your choice. It sounds easy enough – just find a few articles related to your topic and summarize, right? You probably did this type of annotated bibliography as an undergraduate and are pretty optimistic about doing another one. As the professor and other classmates talk more about the demands and expectations for this literature review, however, you may begin to feel less confident. If it’s any consolation, you are not alone.

Writing a literature review involves a synthesis of a complex range of analytical and rhetorical skills as well as academic writing skills, and an understanding of what is meant by critical analysis and argument.(Turner & Bitchener, 2008).

At the same time, there is often a disconnect between what faculty expect in terms of research and writing skills and what incoming graduate students understand about how to conduct a literature review. At the graduate level, and especially when preparing a thesis or dissertation, the literature review is a high-stakes document that introduces the novice researcher to the scholarly conversation of his/her discipline for the first time. Students are often surprised that the specific research and writing skills needed to do a graduate-level literature review aren’t taught in class, while faculty may assume students already have these skills (Harris, 2011). As a result, “most graduate students receive little or no formal training in how to analyze and synthesize the research literature in their field” (Boote & Beile, 2005, p. 5). It is for these students that we write this book.

Literature Reviews for Education and Nursing Graduate Students introduces you to the components of the stand-alone literature review and prepares you to write one of your own. This open textbook is designed to help students in graduate-level nursing and education programs recognize the significant role the literature review plays in the research process and synthesize and cite key sources with confidence. Although specific examples are generally nursing or education related, most of the content is also applicable to other students in the social sciences. Likewise, this textbook is openly licensed, meaning it is available at no cost to anyone in the world who would like to use it. Instructors (and others) may freely edit or modify it and assign as much or as little as needed.

Literature Reviews for Education and Nursing Graduate Students is written for new graduate students and novice researchers just entering the work of their chosen discipline. It is meant to assist “students who can complete course assignments to scholars who can make a contribution to their respective fields.” (Switzer & Perdue, 2011, p. 12). The book was written by two librarians with expertise guiding nursing and education graduate students through the literature review research and writing process. We include in the book examples from the literature of nursing and education to facilitate a greater understanding of what it means to be a successful graduate student. Our intent is to promote the idea that the literature review is a dynamic and complex synthesis of research and writing that is quite different than an annotated bibliography.

Literature Reviews for Education and Nursing Graduate Students covers topics related to literature review research and writing. Chapter 1 provides an overview of literature reviews and their purpose. Chapters 2 and 3 relate to getting started with the review, including how to develop a research question or hypothesis. Chapters 4 and 5 deal with the research process, that is, where to find relevant sources and how to evaluate their credibility. Chapters 6 and 7 discuss how to document sources and, one of the most difficult tasks novice researchers face, how to synthesize information. Chapter 8 is focused on writing your own literature review. A short conclusion and an answer key to questions asked in previous chapters complete the text. Each chapter begins with a summary of learning objectives for that chapter and concludes with a set of questions to assess your understanding of the topics covered. Examples, tutorials, videos, additional resources, websites and/or activities are provided. Finally, at the end of each chapter you will find a list of works cited as well as image attributions.

Although this textbook does not contain all of the answers you will need to successfully write a literature review, the authors hope that when used in combination with all of the other experiences you will have as a graduate student, it will help you to become the researcher and scholar you want to be.

Boote, D.N., & Beile, P. (2005). Scholars before researchers: On the centrality of the dissertation literature review in research preparation. Educational Researcher 34(6), 3-15.

Harris, C.S. (2011). The case for partnering doctoral students with librarians: A synthesis of the literatures. Library Review 60(7), 599-620.

Switzer, A., & Perdue, A.S. (2011). Dissertation 101: A research and writing intervention for education graduate students. Education Libraries 34(1), 4-14.

Turner, E., & Bitchener, J. (2008). An approach to teaching the writing of literature reviews. Zeitschrift Schreiben. https://zeitschrift-schreiben.eu/globalassets/zeitschrift-schreiben.eu/2008/turner_approach_teaching.pdf

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BMC Med Res Methodol

Defining the process to literature searching in systematic reviews: a literature review of guidance and supporting studies

Chris cooper.

1 Institute of Health Research, University of Exeter Medical School, Exeter, UK

Andrew Booth

2 HEDS, School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK

Jo Varley-Campbell

Nicky britten.

3 Institute of Health Research, University of Exeter Medical School, Exeter, UK

Ruth Garside

4 European Centre for Environment and Human Health, University of Exeter Medical School, Truro, UK

Associated Data

Systematic literature searching is recognised as a critical component of the systematic review process. It involves a systematic search for studies and aims for a transparent report of study identification, leaving readers clear about what was done to identify studies, and how the findings of the review are situated in the relevant evidence.

The purpose of this review is to determine if a shared model of the literature searching process can be detected across systematic review guidance documents and, if so, how this process is reported in the guidance and supported by published studies.

A literature review.

Two types of literature were reviewed: guidance and published studies. Nine guidance documents were identified, including: The Cochrane and Campbell Handbooks. Published studies were identified through ‘pearl growing’, citation chasing, a search of PubMed using the systematic review methods filter, and the authors’ topic knowledge.

The relevant sections within each guidance document were then read and re-read, with the aim of determining key methodological stages. Methodological stages were identified and defined. This data was reviewed to identify agreements and areas of unique guidance between guidance documents. Consensus across multiple guidance documents was used to inform selection of ‘key stages’ in the process of literature searching.

Eight key stages were determined relating specifically to literature searching in systematic reviews. They were: who should literature search, aims and purpose of literature searching, preparation, the search strategy, searching databases, supplementary searching, managing references and reporting the search process.

Conclusions

Eight key stages to the process of literature searching in systematic reviews were identified. These key stages are consistently reported in the nine guidance documents, suggesting consensus on the key stages of literature searching, and therefore the process of literature searching as a whole, in systematic reviews. Further research to determine the suitability of using the same process of literature searching for all types of systematic review is indicated.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0545-3) contains supplementary material, which is available to authorized users.

Systematic literature searching is recognised as a critical component of the systematic review process. It involves a systematic search for studies and aims for a transparent report of study identification, leaving review stakeholders clear about what was done to identify studies, and how the findings of the review are situated in the relevant evidence.

Information specialists and review teams appear to work from a shared and tacit model of the literature search process. How this tacit model has developed and evolved is unclear, and it has not been explicitly examined before. This is in contrast to the information science literature, which has developed information processing models as an explicit basis for dialogue and empirical testing. Without an explicit model, research in the process of systematic literature searching will remain immature and potentially uneven, and the development of shared information models will be assumed but never articulated.

One way of developing such a conceptual model is by formally examining the implicit “programme theory” as embodied in key methodological texts. The aim of this review is therefore to determine if a shared model of the literature searching process in systematic reviews can be detected across guidance documents and, if so, how this process is reported and supported.

Identifying guidance

Key texts (henceforth referred to as “guidance”) were identified based upon their accessibility to, and prominence within, United Kingdom systematic reviewing practice. The United Kingdom occupies a prominent position in the science of health information retrieval, as quantified by such objective measures as the authorship of papers, the number of Cochrane groups based in the UK, membership and leadership of groups such as the Cochrane Information Retrieval Methods Group, the HTA-I Information Specialists’ Group and historic association with such centres as the UK Cochrane Centre, the NHS Centre for Reviews and Dissemination, the Centre for Evidence Based Medicine and the National Institute for Clinical Excellence (NICE). Coupled with the linguistic dominance of English within medical and health science and the science of systematic reviews more generally, this offers a justification for a purposive sample that favours UK, European and Australian guidance documents.

Nine guidance documents were identified. These documents provide guidance for different types of reviews, namely: reviews of interventions, reviews of health technologies, reviews of qualitative research studies, reviews of social science topics, and reviews to inform guidance.

Whilst these guidance documents occasionally offer additional guidance on other types of systematic reviews, we have focused on the core and stated aims of these documents as they relate to literature searching. Table 1 sets out: the guidance document, the version audited, their core stated focus, and a bibliographical pointer to the main guidance relating to literature searching.

Guidance documents audited for this literature review

Once a list of key guidance documents was determined, it was checked by six senior information professionals based in the UK for relevance to current literature searching in systematic reviews.

Identifying supporting studies

In addition to identifying guidance, the authors sought to populate an evidence base of supporting studies (henceforth referred to as “studies”) that contribute to existing search practice. Studies were first identified by the authors from their knowledge on this topic area and, subsequently, through systematic citation chasing key studies (‘pearls’ [ 1 ]) located within each key stage of the search process. These studies are identified in Additional file 1 : Appendix Table 1. Citation chasing was conducted by analysing the bibliography of references for each study (backwards citation chasing) and through Google Scholar (forward citation chasing). A search of PubMed using the systematic review methods filter was undertaken in August 2017 (see Additional file 1 ). The search terms used were: (literature search*[Title/Abstract]) AND sysrev_methods[sb] and 586 results were returned. These results were sifted for relevance to the key stages in Fig. 1 by CC.

An external file that holds a picture, illustration, etc.
Object name is 12874_2018_545_Fig1_HTML.jpg

The key stages of literature search guidance as identified from nine key texts

Extracting the data

To reveal the implicit process of literature searching within each guidance document, the relevant sections (chapters) on literature searching were read and re-read, with the aim of determining key methodological stages. We defined a key methodological stage as a distinct step in the overall process for which specific guidance is reported, and action is taken, that collectively would result in a completed literature search.

The chapter or section sub-heading for each methodological stage was extracted into a table using the exact language as reported in each guidance document. The lead author (CC) then read and re-read these data, and the paragraphs of the document to which the headings referred, summarising section details. This table was then reviewed, using comparison and contrast to identify agreements and areas of unique guidance. Consensus across multiple guidelines was used to inform selection of ‘key stages’ in the process of literature searching.

Having determined the key stages to literature searching, we then read and re-read the sections relating to literature searching again, extracting specific detail relating to the methodological process of literature searching within each key stage. Again, the guidance was then read and re-read, first on a document-by-document-basis and, secondly, across all the documents above, to identify both commonalities and areas of unique guidance.

Results and discussion

Our findings.

We were able to identify consensus across the guidance on literature searching for systematic reviews suggesting a shared implicit model within the information retrieval community. Whilst the structure of the guidance varies between documents, the same key stages are reported, even where the core focus of each document is different. We were able to identify specific areas of unique guidance, where a document reported guidance not summarised in other documents, together with areas of consensus across guidance.

Unique guidance

Only one document provided guidance on the topic of when to stop searching [ 2 ]. This guidance from 2005 anticipates a topic of increasing importance with the current interest in time-limited (i.e. “rapid”) reviews. Quality assurance (or peer review) of literature searches was only covered in two guidance documents [ 3 , 4 ]. This topic has emerged as increasingly important as indicated by the development of the PRESS instrument [ 5 ]. Text mining was discussed in four guidance documents [ 4 , 6 – 8 ] where the automation of some manual review work may offer efficiencies in literature searching [ 8 ].

Agreement between guidance: Defining the key stages of literature searching

Where there was agreement on the process, we determined that this constituted a key stage in the process of literature searching to inform systematic reviews.

From the guidance, we determined eight key stages that relate specifically to literature searching in systematic reviews. These are summarised at Fig. Fig.1. 1 . The data extraction table to inform Fig. Fig.1 1 is reported in Table 2 . Table Table2 2 reports the areas of common agreement and it demonstrates that the language used to describe key stages and processes varies significantly between guidance documents.

The order of literature search methods as presented in the guidance documents

For each key stage, we set out the specific guidance, followed by discussion on how this guidance is situated within the wider literature.

Key stage one: Deciding who should undertake the literature search

The guidance.

Eight documents provided guidance on who should undertake literature searching in systematic reviews [ 2 , 4 , 6 – 11 ]. The guidance affirms that people with relevant expertise of literature searching should ‘ideally’ be included within the review team [ 6 ]. Information specialists (or information scientists), librarians or trial search co-ordinators (TSCs) are indicated as appropriate researchers in six guidance documents [ 2 , 7 – 11 ].

How the guidance corresponds to the published studies

The guidance is consistent with studies that call for the involvement of information specialists and librarians in systematic reviews [ 12 – 26 ] and which demonstrate how their training as ‘expert searchers’ and ‘analysers and organisers of data’ can be put to good use [ 13 ] in a variety of roles [ 12 , 16 , 20 , 21 , 24 – 26 ]. These arguments make sense in the context of the aims and purposes of literature searching in systematic reviews, explored below. The need for ‘thorough’ and ‘replicable’ literature searches was fundamental to the guidance and recurs in key stage two. Studies have found poor reporting, and a lack of replicable literature searches, to be a weakness in systematic reviews [ 17 , 18 , 27 , 28 ] and they argue that involvement of information specialists/ librarians would be associated with better reporting and better quality literature searching. Indeed, Meert et al. [ 29 ] demonstrated that involving a librarian as a co-author to a systematic review correlated with a higher score in the literature searching component of a systematic review [ 29 ]. As ‘new styles’ of rapid and scoping reviews emerge, where decisions on how to search are more iterative and creative, a clear role is made here too [ 30 ].

Knowing where to search for studies was noted as important in the guidance, with no agreement as to the appropriate number of databases to be searched [ 2 , 6 ]. Database (and resource selection more broadly) is acknowledged as a relevant key skill of information specialists and librarians [ 12 , 15 , 16 , 31 ].

Whilst arguments for including information specialists and librarians in the process of systematic review might be considered self-evident, Koffel and Rethlefsen [ 31 ] have questioned if the necessary involvement is actually happening [ 31 ].

Key stage two: Determining the aim and purpose of a literature search

The aim: Five of the nine guidance documents use adjectives such as ‘thorough’, ‘comprehensive’, ‘transparent’ and ‘reproducible’ to define the aim of literature searching [ 6 – 10 ]. Analogous phrases were present in a further three guidance documents, namely: ‘to identify the best available evidence’ [ 4 ] or ‘the aim of the literature search is not to retrieve everything. It is to retrieve everything of relevance’ [ 2 ] or ‘A systematic literature search aims to identify all publications relevant to the particular research question’ [ 3 ]. The Joanna Briggs Institute reviewers’ manual was the only guidance document where a clear statement on the aim of literature searching could not be identified. The purpose of literature searching was defined in three guidance documents, namely to minimise bias in the resultant review [ 6 , 8 , 10 ]. Accordingly, eight of nine documents clearly asserted that thorough and comprehensive literature searches are required as a potential mechanism for minimising bias.

The need for thorough and comprehensive literature searches appears as uniform within the eight guidance documents that describe approaches to literature searching in systematic reviews of effectiveness. Reviews of effectiveness (of intervention or cost), accuracy and prognosis, require thorough and comprehensive literature searches to transparently produce a reliable estimate of intervention effect. The belief that all relevant studies have been ‘comprehensively’ identified, and that this process has been ‘transparently’ reported, increases confidence in the estimate of effect and the conclusions that can be drawn [ 32 ]. The supporting literature exploring the need for comprehensive literature searches focuses almost exclusively on reviews of intervention effectiveness and meta-analysis. Different ‘styles’ of review may have different standards however; the alternative, offered by purposive sampling, has been suggested in the specific context of qualitative evidence syntheses [ 33 ].

What is a comprehensive literature search?

Whilst the guidance calls for thorough and comprehensive literature searches, it lacks clarity on what constitutes a thorough and comprehensive literature search, beyond the implication that all of the literature search methods in Table Table2 2 should be used to identify studies. Egger et al. [ 34 ], in an empirical study evaluating the importance of comprehensive literature searches for trials in systematic reviews, defined a comprehensive search for trials as:

a search not restricted to English language;
where Cochrane CENTRAL or at least two other electronic databases had been searched (such as MEDLINE or EMBASE); and
at least one of the following search methods has been used to identify unpublished trials: searches for (I) conference abstracts, (ii) theses, (iii) trials registers; and (iv) contacts with experts in the field [ 34 ].

Tricco et al. (2008) used a similar threshold of bibliographic database searching AND a supplementary search method in a review when examining the risk of bias in systematic reviews. Their criteria were: one database (limited using the Cochrane Highly Sensitive Search Strategy (HSSS)) and handsearching [ 35 ].

Together with the guidance, this would suggest that comprehensive literature searching requires the use of BOTH bibliographic database searching AND supplementary search methods.

Comprehensiveness in literature searching, in the sense of how much searching should be undertaken, remains unclear. Egger et al. recommend that ‘investigators should consider the type of literature search and degree of comprehension that is appropriate for the review in question, taking into account budget and time constraints’ [ 34 ]. This view tallies with the Cochrane Handbook, which stipulates clearly, that study identification should be undertaken ‘within resource limits’ [ 9 ]. This would suggest that the limitations to comprehension are recognised but it raises questions on how this is decided and reported [ 36 ].

What is the point of comprehensive literature searching?

The purpose of thorough and comprehensive literature searches is to avoid missing key studies and to minimize bias [ 6 , 8 , 10 , 34 , 37 – 39 ] since a systematic review based only on published (or easily accessible) studies may have an exaggerated effect size [ 35 ]. Felson (1992) sets out potential biases that could affect the estimate of effect in a meta-analysis [ 40 ] and Tricco et al. summarize the evidence concerning bias and confounding in systematic reviews [ 35 ]. Egger et al. point to non-publication of studies, publication bias, language bias and MEDLINE bias, as key biases [ 34 , 35 , 40 – 46 ]. Comprehensive searches are not the sole factor to mitigate these biases but their contribution is thought to be significant [ 2 , 32 , 34 ]. Fehrmann (2011) suggests that ‘the search process being described in detail’ and that, where standard comprehensive search techniques have been applied, increases confidence in the search results [ 32 ].

Does comprehensive literature searching work?

Egger et al., and other study authors, have demonstrated a change in the estimate of intervention effectiveness where relevant studies were excluded from meta-analysis [ 34 , 47 ]. This would suggest that missing studies in literature searching alters the reliability of effectiveness estimates. This is an argument for comprehensive literature searching. Conversely, Egger et al. found that ‘comprehensive’ searches still missed studies and that comprehensive searches could, in fact, introduce bias into a review rather than preventing it, through the identification of low quality studies then being included in the meta-analysis [ 34 ]. Studies query if identifying and including low quality or grey literature studies changes the estimate of effect [ 43 , 48 ] and question if time is better invested updating systematic reviews rather than searching for unpublished studies [ 49 ], or mapping studies for review as opposed to aiming for high sensitivity in literature searching [ 50 ].

Aim and purpose beyond reviews of effectiveness

The need for comprehensive literature searches is less certain in reviews of qualitative studies, and for reviews where a comprehensive identification of studies is difficult to achieve (for example, in Public health) [ 33 , 51 – 55 ]. Literature searching for qualitative studies, and in public health topics, typically generates a greater number of studies to sift than in reviews of effectiveness [ 39 ] and demonstrating the ‘value’ of studies identified or missed is harder [ 56 ], since the study data do not typically support meta-analysis. Nussbaumer-Streit et al. (2016) have registered a review protocol to assess whether abbreviated literature searches (as opposed to comprehensive literature searches) has an impact on conclusions across multiple bodies of evidence, not only on effect estimates [ 57 ] which may develop this understanding. It may be that decision makers and users of systematic reviews are willing to trade the certainty from a comprehensive literature search and systematic review in exchange for different approaches to evidence synthesis [ 58 ], and that comprehensive literature searches are not necessarily a marker of literature search quality, as previously thought [ 36 ]. Different approaches to literature searching [ 37 , 38 , 59 – 62 ] and developing the concept of when to stop searching are important areas for further study [ 36 , 59 ].

The study by Nussbaumer-Streit et al. has been published since the submission of this literature review [ 63 ]. Nussbaumer-Streit et al. (2018) conclude that abbreviated literature searches are viable options for rapid evidence syntheses, if decision-makers are willing to trade the certainty from a comprehensive literature search and systematic review, but that decision-making which demands detailed scrutiny should still be based on comprehensive literature searches [ 63 ].

Key stage three: Preparing for the literature search

Six documents provided guidance on preparing for a literature search [ 2 , 3 , 6 , 7 , 9 , 10 ]. The Cochrane Handbook clearly stated that Cochrane authors (i.e. researchers) should seek advice from a trial search co-ordinator (i.e. a person with specific skills in literature searching) ‘before’ starting a literature search [ 9 ].

Two key tasks were perceptible in preparing for a literature searching [ 2 , 6 , 7 , 10 , 11 ]. First, to determine if there are any existing or on-going reviews, or if a new review is justified [ 6 , 11 ]; and, secondly, to develop an initial literature search strategy to estimate the volume of relevant literature (and quality of a small sample of relevant studies [ 10 ]) and indicate the resources required for literature searching and the review of the studies that follows [ 7 , 10 ].

Three documents summarised guidance on where to search to determine if a new review was justified [ 2 , 6 , 11 ]. These focused on searching databases of systematic reviews (The Cochrane Database of Systematic Reviews (CDSR) and the Database of Abstracts of Reviews of Effects (DARE)), institutional registries (including PROSPERO), and MEDLINE [ 6 , 11 ]. It is worth noting, however, that as of 2015, DARE (and NHS EEDs) are no longer being updated and so the relevance of this (these) resource(s) will diminish over-time [ 64 ]. One guidance document, ‘Systematic reviews in the Social Sciences’, noted, however, that databases are not the only source of information and unpublished reports, conference proceeding and grey literature may also be required, depending on the nature of the review question [ 2 ].

Two documents reported clearly that this preparation (or ‘scoping’) exercise should be undertaken before the actual search strategy is developed [ 7 , 10 ]).

The guidance offers the best available source on preparing the literature search with the published studies not typically reporting how their scoping informed the development of their search strategies nor how their search approaches were developed. Text mining has been proposed as a technique to develop search strategies in the scoping stages of a review although this work is still exploratory [ 65 ]. ‘Clustering documents’ and word frequency analysis have also been tested to identify search terms and studies for review [ 66 , 67 ]. Preparing for literature searches and scoping constitutes an area for future research.

Key stage four: Designing the search strategy

The Population, Intervention, Comparator, Outcome (PICO) structure was the commonly reported structure promoted to design a literature search strategy. Five documents suggested that the eligibility criteria or review question will determine which concepts of PICO will be populated to develop the search strategy [ 1 , 4 , 7 – 9 ]. The NICE handbook promoted multiple structures, namely PICO, SPICE (Setting, Perspective, Intervention, Comparison, Evaluation) and multi-stranded approaches [ 4 ].

With the exclusion of The Joanna Briggs Institute reviewers’ manual, the guidance offered detail on selecting key search terms, synonyms, Boolean language, selecting database indexing terms and combining search terms. The CEE handbook suggested that ‘search terms may be compiled with the help of the commissioning organisation and stakeholders’ [ 10 ].

The use of limits, such as language or date limits, were discussed in all documents [ 2 – 4 , 6 – 11 ].

Search strategy structure

The guidance typically relates to reviews of intervention effectiveness so PICO – with its focus on intervention and comparator - is the dominant model used to structure literature search strategies [ 68 ]. PICOs – where the S denotes study design - is also commonly used in effectiveness reviews [ 6 , 68 ]. As the NICE handbook notes, alternative models to structure literature search strategies have been developed and tested. Booth provides an overview on formulating questions for evidence based practice [ 69 ] and has developed a number of alternatives to the PICO structure, namely: BeHEMoTh (Behaviour of interest; Health context; Exclusions; Models or Theories) for use when systematically identifying theory [ 55 ]; SPICE (Setting, Perspective, Intervention, Comparison, Evaluation) for identification of social science and evaluation studies [ 69 ] and, working with Cooke and colleagues, SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research type) [ 70 ]. SPIDER has been compared to PICO and PICOs in a study by Methley et al. [ 68 ].

The NICE handbook also suggests the use of multi-stranded approaches to developing literature search strategies [ 4 ]. Glanville developed this idea in a study by Whitting et al. [ 71 ] and a worked example of this approach is included in the development of a search filter by Cooper et al. [ 72 ].

Writing search strategies: Conceptual and objective approaches

Hausner et al. [ 73 ] provide guidance on writing literature search strategies, delineating between conceptually and objectively derived approaches. The conceptual approach, advocated by and explained in the guidance documents, relies on the expertise of the literature searcher to identify key search terms and then develop key terms to include synonyms and controlled syntax. Hausner and colleagues set out the objective approach [ 73 ] and describe what may be done to validate it [ 74 ].

The use of limits

The guidance documents offer direction on the use of limits within a literature search. Limits can be used to focus literature searching to specific study designs or by other markers (such as by date) which limits the number of studies returned by a literature search. The use of limits should be described and the implications explored [ 34 ] since limiting literature searching can introduce bias (explored above). Craven et al. have suggested the use of a supporting narrative to explain decisions made in the process of developing literature searches and this advice would usefully capture decisions on the use of search limits [ 75 ].

Key stage five: Determining the process of literature searching and deciding where to search (bibliographic database searching)

Table Table2 2 summarises the process of literature searching as reported in each guidance document. Searching bibliographic databases was consistently reported as the ‘first step’ to literature searching in all nine guidance documents.

Three documents reported specific guidance on where to search, in each case specific to the type of review their guidance informed, and as a minimum requirement [ 4 , 9 , 11 ]. Seven of the key guidance documents suggest that the selection of bibliographic databases depends on the topic of review [ 2 – 4 , 6 – 8 , 10 ], with two documents noting the absence of an agreed standard on what constitutes an acceptable number of databases searched [ 2 , 6 ].

The guidance documents summarise ‘how to’ search bibliographic databases in detail and this guidance is further contextualised above in terms of developing the search strategy. The documents provide guidance of selecting bibliographic databases, in some cases stating acceptable minima (i.e. The Cochrane Handbook states Cochrane CENTRAL, MEDLINE and EMBASE), and in other cases simply listing bibliographic database available to search. Studies have explored the value in searching specific bibliographic databases, with Wright et al. (2015) noting the contribution of CINAHL in identifying qualitative studies [ 76 ], Beckles et al. (2013) questioning the contribution of CINAHL to identifying clinical studies for guideline development [ 77 ], and Cooper et al. (2015) exploring the role of UK-focused bibliographic databases to identify UK-relevant studies [ 78 ]. The host of the database (e.g. OVID or ProQuest) has been shown to alter the search returns offered. Younger and Boddy [ 79 ] report differing search returns from the same database (AMED) but where the ‘host’ was different [ 79 ].

The average number of bibliographic database searched in systematic reviews has risen in the period 1994–2014 (from 1 to 4) [ 80 ] but there remains (as attested to by the guidance) no consensus on what constitutes an acceptable number of databases searched [ 48 ]. This is perhaps because thinking about the number of databases searched is the wrong question, researchers should be focused on which databases were searched and why, and which databases were not searched and why. The discussion should re-orientate to the differential value of sources but researchers need to think about how to report this in studies to allow findings to be generalised. Bethel (2017) has proposed ‘search summaries’, completed by the literature searcher, to record where included studies were identified, whether from database (and which databases specifically) or supplementary search methods [ 81 ]. Search summaries document both yield and accuracy of searches, which could prospectively inform resource use and decisions to search or not to search specific databases in topic areas. The prospective use of such data presupposes, however, that past searches are a potential predictor of future search performance (i.e. that each topic is to be considered representative and not unique). In offering a body of practice, this data would be of greater practicable use than current studies which are considered as little more than individual case studies [ 82 – 90 ].

When to database search is another question posed in the literature. Beyer et al. [ 91 ] report that databases can be prioritised for literature searching which, whilst not addressing the question of which databases to search, may at least bring clarity as to which databases to search first [ 91 ]. Paradoxically, this links to studies that suggest PubMed should be searched in addition to MEDLINE (OVID interface) since this improves the currency of systematic reviews [ 92 , 93 ]. Cooper et al. (2017) have tested the idea of database searching not as a primary search method (as suggested in the guidance) but as a supplementary search method in order to manage the volume of studies identified for an environmental effectiveness systematic review. Their case study compared the effectiveness of database searching versus a protocol using supplementary search methods and found that the latter identified more relevant studies for review than searching bibliographic databases [ 94 ].

Key stage six: Determining the process of literature searching and deciding where to search (supplementary search methods)

Table Table2 2 also summaries the process of literature searching which follows bibliographic database searching. As Table Table2 2 sets out, guidance that supplementary literature search methods should be used in systematic reviews recurs across documents, but the order in which these methods are used, and the extent to which they are used, varies. We noted inconsistency in the labelling of supplementary search methods between guidance documents.

Rather than focus on the guidance on how to use the methods (which has been summarised in a recent review [ 95 ]), we focus on the aim or purpose of supplementary search methods.

The Cochrane Handbook reported that ‘efforts’ to identify unpublished studies should be made [ 9 ]. Four guidance documents [ 2 , 3 , 6 , 9 ] acknowledged that searching beyond bibliographic databases was necessary since ‘databases are not the only source of literature’ [ 2 ]. Only one document reported any guidance on determining when to use supplementary methods. The IQWiG handbook reported that the use of handsearching (in their example) could be determined on a ‘case-by-case basis’ which implies that the use of these methods is optional rather than mandatory. This is in contrast to the guidance (above) on bibliographic database searching.

The issue for supplementary search methods is similar in many ways to the issue of searching bibliographic databases: demonstrating value. The purpose and contribution of supplementary search methods in systematic reviews is increasingly acknowledged [ 37 , 61 , 62 , 96 – 101 ] but understanding the value of the search methods to identify studies and data is unclear. In a recently published review, Cooper et al. (2017) reviewed the literature on supplementary search methods looking to determine the advantages, disadvantages and resource implications of using supplementary search methods [ 95 ]. This review also summarises the key guidance and empirical studies and seeks to address the question on when to use these search methods and when not to [ 95 ]. The guidance is limited in this regard and, as Table Table2 2 demonstrates, offers conflicting advice on the order of searching, and the extent to which these search methods should be used in systematic reviews.

Key stage seven: Managing the references

Five of the documents provided guidance on managing references, for example downloading, de-duplicating and managing the output of literature searches [ 2 , 4 , 6 , 8 , 10 ]. This guidance typically itemised available bibliographic management tools rather than offering guidance on how to use them specifically [ 2 , 4 , 6 , 8 ]. The CEE handbook provided guidance on importing data where no direct export option is available (e.g. web-searching) [ 10 ].

The literature on using bibliographic management tools is not large relative to the number of ‘how to’ videos on platforms such as YouTube (see for example [ 102 ]). These YouTube videos confirm the overall lack of ‘how to’ guidance identified in this study and offer useful instruction on managing references. Bramer et al. set out methods for de-duplicating data and reviewing references in Endnote [ 103 , 104 ] and Gall tests the direct search function within Endnote to access databases such as PubMed, finding a number of limitations [ 105 ]. Coar et al. and Ahmed et al. consider the role of the free-source tool, Zotero [ 106 , 107 ]. Managing references is a key administrative function in the process of review particularly for documenting searches in PRISMA guidance.

Key stage eight: Documenting the search

The Cochrane Handbook was the only guidance document to recommend a specific reporting guideline: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [ 9 ]. Six documents provided guidance on reporting the process of literature searching with specific criteria to report [ 3 , 4 , 6 , 8 – 10 ]. There was consensus on reporting: the databases searched (and the host searched by), the search strategies used, and any use of limits (e.g. date, language, search filters (The CRD handbook called for these limits to be justified [ 6 ])). Three guidance documents reported that the number of studies identified should be recorded [ 3 , 6 , 10 ]. The number of duplicates identified [ 10 ], the screening decisions [ 3 ], a comprehensive list of grey literature sources searched (and full detail for other supplementary search methods) [ 8 ], and an annotation of search terms tested but not used [ 4 ] were identified as unique items in four documents.

The Cochrane Handbook was the only guidance document to note that the full search strategies for each database should be included in the Additional file 1 of the review [ 9 ].

All guidance documents should ultimately deliver completed systematic reviews that fulfil the requirements of the PRISMA reporting guidelines [ 108 ]. The guidance broadly requires the reporting of data that corresponds with the requirements of the PRISMA statement although documents typically ask for diverse and additional items [ 108 ]. In 2008, Sampson et al. observed a lack of consensus on reporting search methods in systematic reviews [ 109 ] and this remains the case as of 2017, as evidenced in the guidance documents, and in spite of the publication of the PRISMA guidelines in 2009 [ 110 ]. It is unclear why the collective guidance does not more explicitly endorse adherence to the PRISMA guidance.

Reporting of literature searching is a key area in systematic reviews since it sets out clearly what was done and how the conclusions of the review can be believed [ 52 , 109 ]. Despite strong endorsement in the guidance documents, specifically supported in PRISMA guidance, and other related reporting standards too (such as ENTREQ for qualitative evidence synthesis, STROBE for reviews of observational studies), authors still highlight the prevalence of poor standards of literature search reporting [ 31 , 110 – 119 ]. To explore issues experienced by authors in reporting literature searches, and look at uptake of PRISMA, Radar et al. [ 120 ] surveyed over 260 review authors to determine common problems and their work summaries the practical aspects of reporting literature searching [ 120 ]. Atkinson et al. [ 121 ] have also analysed reporting standards for literature searching, summarising recommendations and gaps for reporting search strategies [ 121 ].

One area that is less well covered by the guidance, but nevertheless appears in this literature, is the quality appraisal or peer review of literature search strategies. The PRESS checklist is the most prominent and it aims to develop evidence-based guidelines to peer review of electronic search strategies [ 5 , 122 , 123 ]. A corresponding guideline for documentation of supplementary search methods does not yet exist although this idea is currently being explored.

How the reporting of the literature searching process corresponds to critical appraisal tools is an area for further research. In the survey undertaken by Radar et al. (2014), 86% of survey respondents (153/178) identified a need for further guidance on what aspects of the literature search process to report [ 120 ]. The PRISMA statement offers a brief summary of what to report but little practical guidance on how to report it [ 108 ]. Critical appraisal tools for systematic reviews, such as AMSTAR 2 (Shea et al. [ 124 ]) and ROBIS (Whiting et al. [ 125 ]), can usefully be read alongside PRISMA guidance, since they offer greater detail on how the reporting of the literature search will be appraised and, therefore, they offer a proxy on what to report [ 124 , 125 ]. Further research in the form of a study which undertakes a comparison between PRISMA and quality appraisal checklists for systematic reviews would seem to begin addressing the call, identified by Radar et al., for further guidance on what to report [ 120 ].

Limitations

Other handbooks exist.

A potential limitation of this literature review is the focus on guidance produced in Europe (the UK specifically) and Australia. We justify the decision for our selection of the nine guidance documents reviewed in this literature review in section “ Identifying guidance ”. In brief, these nine guidance documents were selected as the most relevant health care guidance that inform UK systematic reviewing practice, given that the UK occupies a prominent position in the science of health information retrieval. We acknowledge the existence of other guidance documents, such as those from North America (e.g. the Agency for Healthcare Research and Quality (AHRQ) [ 126 ], The Institute of Medicine [ 127 ] and the guidance and resources produced by the Canadian Agency for Drugs and Technologies in Health (CADTH) [ 128 ]). We comment further on this directly below.

The handbooks are potentially linked to one another

What is not clear is the extent to which the guidance documents inter-relate or provide guidance uniquely. The Cochrane Handbook, first published in 1994, is notably a key source of reference in guidance and systematic reviews beyond Cochrane reviews. It is not clear to what extent broadening the sample of guidance handbooks to include North American handbooks, and guidance handbooks from other relevant countries too, would alter the findings of this literature review or develop further support for the process model. Since we cannot be clear, we raise this as a potential limitation of this literature review. On our initial review of a sample of North American, and other, guidance documents (before selecting the guidance documents considered in this review), however, we do not consider that the inclusion of these further handbooks would alter significantly the findings of this literature review.

This is a literature review

A further limitation of this review was that the review of published studies is not a systematic review of the evidence for each key stage. It is possible that other relevant studies could help contribute to the exploration and development of the key stages identified in this review.

This literature review would appear to demonstrate the existence of a shared model of the literature searching process in systematic reviews. We call this model ‘the conventional approach’, since it appears to be common convention in nine different guidance documents.

The findings reported above reveal eight key stages in the process of literature searching for systematic reviews. These key stages are consistently reported in the nine guidance documents which suggests consensus on the key stages of literature searching, and therefore the process of literature searching as a whole, in systematic reviews.

In Table Table2, 2 , we demonstrate consensus regarding the application of literature search methods. All guidance documents distinguish between primary and supplementary search methods. Bibliographic database searching is consistently the first method of literature searching referenced in each guidance document. Whilst the guidance uniformly supports the use of supplementary search methods, there is little evidence for a consistent process with diverse guidance across documents. This may reflect differences in the core focus across each document, linked to differences in identifying effectiveness studies or qualitative studies, for instance.

Eight of the nine guidance documents reported on the aims of literature searching. The shared understanding was that literature searching should be thorough and comprehensive in its aim and that this process should be reported transparently so that that it could be reproduced. Whilst only three documents explicitly link this understanding to minimising bias, it is clear that comprehensive literature searching is implicitly linked to ‘not missing relevant studies’ which is approximately the same point.

Defining the key stages in this review helps categorise the scholarship available, and it prioritises areas for development or further study. The supporting studies on preparing for literature searching (key stage three, ‘preparation’) were, for example, comparatively few, and yet this key stage represents a decisive moment in literature searching for systematic reviews. It is where search strategy structure is determined, search terms are chosen or discarded, and the resources to be searched are selected. Information specialists, librarians and researchers, are well placed to develop these and other areas within the key stages we identify.

This review calls for further research to determine the suitability of using the conventional approach. The publication dates of the guidance documents which underpin the conventional approach may raise questions as to whether the process which they each report remains valid for current systematic literature searching. In addition, it may be useful to test whether it is desirable to use the same process model of literature searching for qualitative evidence synthesis as that for reviews of intervention effectiveness, which this literature review demonstrates is presently recommended best practice.

Additional file

Appendix tables and PubMed search strategy. Key studies used for pearl growing per key stage, working data extraction tables and the PubMed search strategy. (DOCX 30 kb)

Acknowledgements

CC acknowledges the supervision offered by Professor Chris Hyde.

This publication forms a part of CC’s PhD. CC’s PhD was funded through the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme (Project Number 16/54/11). The open access fee for this publication was paid for by Exeter Medical School.

RG and NB were partially supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care South West Peninsula.

The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

Abbreviations

Authors’ contributions.

CC conceived the idea for this study and wrote the first draft of the manuscript. CC discussed this publication in PhD supervision with AB and separately with JVC. CC revised the publication with input and comments from AB, JVC, RG and NB. All authors revised the manuscript prior to submission. All authors read and approved the final manuscript.

Ethics approval and consent to participate

Consent for publication, competing interests.

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

Chris Cooper, Email: [email protected] .

Andrew Booth, Email: [email protected] .

Jo Varley-Campbell, Email: [email protected] .

Nicky Britten, Email: [email protected] .

Ruth Garside, Email: [email protected] .

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Apple releases updates for iOS 17.4.1, iPadOS 17.4.1, visionOS 1.1.1

iPadOS on an iPad

A granular update for all three operating systems, iOS 17.4.1, iPadOS 17.4.1, and visionOS 1.1.1 are all available to download to the iPhone , iPad , and Apple Vision Pro .

The update arrives not long after the release of iOS 17.4 and iPadOS 17.4 , which surfaced on March 5 . The 17.4.1 releases also do so without any beta releases being issued.

The new iOS and iPadOS releases have build number 21E236, replacing the previous build for the 17.4 releases, 21E219. The latest visionOS update to 1.1.1 is build number 21O224.

It is unclear exactly what is new in the releases, but the granular update usually signifies bug fixes, performance improvements, and compatibility releases. In the case of iPadOS , this could also mean support for new iPad models.

The patch notes displayed for a manual update mention the updates provide "important bug fixes and security updates," and that it is "recommended for all users." It also includes a link to details of Apple's security releases .

The iOS 17.4 and iPadOS counterpart included many changes, including elements to comply with Europe's DMA , such as support for third-party app stores. The rest of the world enjoyed changes such as a new post-quantum encryption change for iMessage.

At the same time as the updates to the current-gen operating systems, Apple has also issued updates to an older version as well. Updates for iOS 16.7.7 and iPadOS 16.7.7, build number 20H330.

Apple's updates to previous operating systems are often made for compatibility, bug-fixing, or security reasons.

To update devices to iOS 17.4 manually, navigate to Settings, General, then Software Update. Those with automatic updates enabled will see it install within the next few days.

Users can also update visionOS within the Apple Vision Pro by opening Settings then General, followed by Software Updates. Automatic updates can be enabled from the same area.

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Ariba Shahid is a journalist based in Karachi, Pakistan. She primarily covers economic and financial news from Pakistan, along with Karachi-centric stories. Ariba has previously worked at DealStreetAsia and Profit Magazine.

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U.N. chief calls for ‘unfettered’ aid to Gaza as aid groups report imminent famine

Famine may already be happening in northern Gaza, and it risks spreading across the besieged enclave, plunging 2.2 million Palestinians into the broadest and most severe food crisis in the world, the globe’s leading body on food emergencies said Monday.

The new report from a cluster of international organizations and charities known as the Integrated Food Security Phase Classification initiative, or IPC , outlined a devastating situation with up to half the population of Gaza — 1.1 million people — facing catastrophic levels of hunger and starvation between now and July. The most immediately affected areas are in the northern regions, which Israeli forces cut off from the enclave’s southern half and which only a trickle of aid has been able to enter.

Compared with the IPC’s previous analysis in December, acute food insecurity in the Gaza Strip has deepened and widened, with nearly twice as many people projected to suffer those conditions by July. The most dire projection is based on an escalation of the conflict, including a ground offensive in Rafah.

In the IPC’s five-tier classification of food crises, Gaza now has the largest percentage of a population to receive its most severe rating since the body began reporting in 2004, Beth Bechdol, deputy director general at the Food and Agriculture Organization (FAO), told The Washington Post.

By comparison, today in Sudan, Somalia and Afghanistan — where millions are suffering crisis and emergency levels of food insecurity — none of the population falls into the worst tier of catastrophic food shortages, Bechdol said.

People in areas designated at Phase 5 are considered to be “starving” and facing a significantly increased risk of acute malnutrition and death.

“ So, for Gaza to have 1.1 million people in IPC 5 is unprecedented,” she said. She added: “This is 100 percent a man-made crisis. There’s no hurricane, there’s no cyclone, there’s no 100-year flood. There’s no protracted year-on-year drought.”

The report is likely to add fuel to the increasingly sharp criticism of Israel from governments in the United States and Europe about the grim dimensions of the escalating humanitarian crisis in Gaza. On Monday, the European Union’s foreign policy chief, Josep Borrell, repeated his assertion that Israel was using starvation as a “weapon of war.” He noted that German Chancellor Olaf Scholz had recently told Israeli Prime Minister Benjamin Netanyahu that “we cannot stand by and watch Palestinians starve.”

“In Gaza we are no longer on the brink of famine; we are in a state of famine, affecting thousands of people,” Borrell said at the start of a conference on humanitarian aid for Gaza in Brussels. “This is unacceptable. Starvation is used as a weapon of war.”

Moamen al-Harthani, a 29-year-old resident of the northern Gaza town of Jabalya, described how people in the north were eating weeds and other plants to survive.

“There is no rice, no sugar, no beans, no lentils. … No fruit or vegetables,” Harthani said. “People eat the food of animals and livestock,” he said. Unable to find or afford flour, Harthani makes a bread-like substitute out of animal feed.

The IPC, an international initiative to classify food insecurity and malnutrition and assesses conditions, does not issue an official declaration of famine — a move left to senior local authorities or the highest United Nations official in an affected area. A famine designation would elevate the crisis to a major talking point at the U.N. Security Council and compel high-level crisis talks among humanitarian bodies and groups.

Hamas has been using the word famine in its official statements for months. Hamas spokesperson Basem Naim said he did not expect to issue “a new specific and official announcement about determining the beginning or end of the famine.”

On Monday, Israeli authorities denied Philippe Lazzarini, the chief of the U.N. agency for Palestinian refugees (UNRWA), entry into Gaza , he said. “My visit today was supposed to coordinate and improve the humanitarian response,” Lazzarini said, sharing the IPC famine projection. UNRWA is the largest humanitarian aid group serving Gaza but has come under attack from Israel over allegations that a handful of its staff were involved in the Oct 7. attack.

Also on Monday, a Famine Review Committee made up of leading independent international food security, nutrition and mortality experts issued a conclusion that the IPC’s findings were “plausible” and warned that famine in northern Gaza “is now projected and imminent .” It noted that famine conditions for acute food insecurity and malnutrition had already been surpassed, though it said it was unclear if child mortality and non-trauma death rate thresholds had been reached.

A famine in Gaza would follow one that afflicted 80,000 people in South Sudan in 2017 and 490,000 people in Somalia in 2011.

“This is the highest number of people facing catastrophic hunger ever recorded by the Integrated Food Security Classification system — anywhere, anytime,” U.N. Secretary General António Guterres said Monday.

The war has destroyed and upended all parts of Gaza’s food system — from the fruits, vegetables, livestock and fish raised on farms to the bakeries and factories that produced breads and dairy products. The percentage of damaged agriculture land increased from 25 percent to 60 percent between November and January, the report said. It noted that more than 300 barns, 100 agricultural warehouses, 46 farm storage facilities, 119 animal shelters, 200 farms, as well over 600 wells used for irrigation have been destroyed, while most livestock has been abandoned, slaughtered or sold.

During the holy month of Ramadan, Muslims typically have an early-morning, pre-fast bite and then a large meal when fasting ends after sundown. But this year, Gazans told The Post, they are fasting regardless of Ramadan. Since the war began, Harthani said, he has lost around 60 pounds.

Harthani’s wife and 6-week-old child relocated south to Rafah, where they thought it would be safer. But in Rafah, his wife is similarly going hungry, as she can’t afford sufficient food and formula due to sky-high wartime inflation, he said.

Both mother and newborn are weak from malnutrition. His wife recently developed liver disease, Harthani said.

The latest analysis was conducted remotely between Feb. 26 and March 1, by more than 40 experts from 18 agencies, the IPC said. But the new assessment — the IPC’s grimmest to date — suggests that northern Gaza is either already in the grip of famine or could reach that point by May.

The findings in the latest report confirm warnings of impending famine in parts of Gaza, in the absence of a cease-fire, from U.N. and other aid agencies in recent months. At least 27 children have died of malnutrition in recent weeks, local health officials have said, underscoring the vast need.

Humanitarian officials blame the hunger crisis in the north on limited entry points for aid, a time-consuming Israeli inspection process and Israeli attacks on U.N. aid convoys and the police protecting them. Israel denies limiting the flow of aid to Gaza. It has accused the United Nations of failing to distribute food aid to those in need — or diverting it to Hamas .

Aid shipments, the report said, have been constrained by direct strikes on humanitarian convoys, detention of humanitarian staff, road closures, checkpoints and related blockages or delays on main transportation corridors. Road damage from bombardments and traffic of heavy military vehicles as well as an estimated 12,000 metric tons of debris have added to complications.

Palestinian officials say more than 100 people were killed and 700 injured in Gaza City late last month after desperate civilians rushed an aid convoy. The fatal incident prompted the Biden administration to launch food drops into Gaza and express mounting frustration with Israeli controls on aid convoys into the enclave.

According to the report, virtually all households in Gaza are skipping meals every day and adults are reducing their meals so that children can eat. In northern Gaza, people in nearly two-thirds of all households had gone “entire days and nights without eating” at least 10 times in the last 30 days, with 1 in 3 children under the age of 2 “acutely malnourished.”

The IPC blamed the famine-like conditions in Gaza on the “widespread, intense, and relentless conflict” that has forced approximately 1.9 million people, or 85 percent of Gaza’s population, to flee their homes, with over 31,000 fatalities and 73,000 injuries reported by Gaza health authorities.

“The escalation of hostilities has halted supplies of water, food and fuel, causing the collapse of all food-related sectors, including vegetable production, livestock production, and fisheries and aquaculture,” said Maximo Torero Cullen, the FAO’s chief economist.

An earlier IPC assessment of Gaza in December concluded that its entire population was highly food-insecure and at risk of famine.

In addition to the airdrops of small amounts of food, the first aid shipment by sea dispatched by nonprofit World Central Kitchen reached Gaza last week. But experts say these alone cannot contain the emergency.

Ahmed Najjar, 29, a resident of Jabalya, is among the thousands of Gazans who for weeks have gathered late at night at key junctures to try to intercept food trucks entering the north.

On Thursday night, more than 20 people were killed at the Kuwait Roundabout in Gaza City, according to Palestinian officials, who said Israeli forces fired at the crowds. The Israeli military blamed Palestinian gunmen. The Post could not independently confirm these accounts. Najjar said there was shelling by Israeli forces. He watched the injured and dead be pulled from the center of crowds around the trucks and he left without getting any flour.

“The strong eat,” he said of the situation. “The weak die.”

Beatriz Rios contributed to this report.

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Chapter 1: Introduction
1.3.1.2 Empirical. An empirical literature review collects, creates, arranges, and analyzes numeric data reflecting the frequency of themes, topics, authors and/or methods found in existing literature. Empirical literature reviews present their summaries in quantifiable terms using descriptive and inferential statistics.
Writing a Literature Review
A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays).
Literature review as a research methodology: An overview and guidelines
2.1.1. Systematic literature review. What is it and when should we use it? Systematic reviews have foremost been developed within medical science as a way to synthesize research findings in a systematic, transparent, and reproducible way and have been referred to as the gold standard among reviews (Davis et al., 2014).Despite all the advantages of this method, its use has not been overly ...
PDF What is a Literature Review?
unearth literature that is appropriate to your task in hand, a literature review is the process of critically evaluating and summarising that literature. The Purpose of the Literature Review: The Question and Context Conceptualising the Literature Review Think of a topic that interests you in clinical practice. Imagine this as a wide-rimmed,
Writing Your Literature Review
11.7.1 Introduction. In the introduction section of the literature review, you should define the general topic and provide an appropriate context for reviewing the literature. Summarise the overall trends that have emerged from your review of the literature and highlight the significance of your review.
Conducting a Literature Review
When searching for this type of article you can limit part of your search strategy to look for the term "literature review" in the title of the article. See Figure 1.1 below. Figure 1.1. Example of how to search with the term "literature review" in the title.
Introduction to Literature Reviews
A good literature review lays the foundation for the importance of your stated problem and research question. Literature reviews do the following: define a concept. map the research terrain or scope. systemize relationships between concepts. identify gaps in the literature ( Rocco & Plathotnik, 2009, p. 128.
Undertaking a literature review: a step-by-step approach
Abstract. Nowadays, most nurses, pre- and post-qualification, will be required to undertake a literature review at some point, either as part of a course of study, as a key step in the research process, or as part of clinical practice development or policy. For student nurses and novice researchers it is often seen as a difficult undertaking.
1.1 Getting started
Common social issues that are studied include "health care, substance abuse, community violence, family issues, child welfare, aging, well-being and resiliency, and the strengths and needs of underserved populations" (ANSWER, n.d., para. 2). This list is certainly not exhaustive. Social workers may study any area that impacts their practice.
(PDF) Literature review as a research methodology: An overview and
Jan 2024. View. Mei Hong Gao. In this paper, the author adopts the literature review research methods, starting from the perspective of the sports science research methodology, and discussing the ...
Literature Reviews for Education and Nursing Graduate Students
Literature Reviews for Education and Nursing Graduate Students is an open textbook designed for students in graduate-level nursing and education programs. Its intent is to recognize the significant role the literature review plays in the research process and to prepare students for the work that goes into writing one. Developed for new graduate students and novice researchers just entering ...
Literature Review
Unless your School specifies the length, you can use the following as a rough guide: Around 15-30% of the whole thesis ( see FAQs) OR. Your thesis is expected to be 60% your own work. If your literature review is more than 40% of your thesis, it's probably too long.
3.1 What is a literature review?
A literature review is a compilation of the most significant previously published research on your topic. Unlike an annotated bibliography or a research paper you may have written in other classes, your literature review will outline, evaluate, and synthesize relevant research and relate those sources to your own research question.
(PDF) Literature Reviews, Conceptual Frameworks, and Theoretical
The studies often include a literature review, which is a synthesis of major themes in the literature, or conceptual frameworks, which can be defined as a network of concepts relevant to the study ...
Preface
Literature Reviews for Education and Nursing Graduate Students is written for new graduate students and novice researchers just entering the work of their chosen discipline. It is meant to assist "students who can complete course assignments to scholars who can make a contribution to their respective fields." (Switzer & Perdue, 2011, p. 12).
Defining the process to literature searching in systematic reviews: a
Background. Systematic literature searching is recognised as a critical component of the systematic review process. It involves a systematic search for studies and aims for a transparent report of study identification, leaving readers clear about what was done to identify studies, and how the findings of the review are situated in the relevant evidence.
The integrative literature review as a research method: A demonstration
An Integrative Literature Review (ILR) allows researchers to go beyond an analysis and synthesis of primary research findings and provides new insights and summarised knowledge about a specific topic. Although an ILR aims to follow similar approaches to that of a systematic review, it allows for the inclusion of both primary research studies ...
PDF Approaches to learning: Literature review
Approaches to learning: Literature review 2 Some of the sources were obtained through the snowballing method by checking the references lists of the existing sources. Overview of this literature review In section 1, common educational objectives across national and international educational systems are reviewed.
(PDF) Chapter 1: Literature Review
Chapter 1: Literature Review. May 2014; In book: Molecular Characterization of Full Genome HBV sequences from an urban hospital cohort in Pretoria, South Africa [thesis] (pp.1-48) ... (± 0.1-1 % ...
Social Cognitive Theory: An Agentic Perspective
Abstract The capacity to exercise control over the nature and quality of one's life is the essence of humanness. Human agency is characterized by a number of core features that operate through phenomenal and functional consciousness. These include the temporal extension of agency through intentionality and forethought, self-regulation by self-reactive influence, and self-reflectiveness ...
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Apple has released iOS 17.4.1 and iPadOS 17.4.1 to the public, at the same time as bringing visionOS up to 1.1.1 while also slipping out iOS 16.7.7.
CHAPTER TWO. LITERATURE REVIEW. 2.1 Introduction
LITERATURE REVIEW. 2.1 Introduction. This chapter presents a review of literature pertinent to the study as presented by various. researchers, scholars', analysts and authors. It summarizes ...
IMF says it reaches a staff level agreement with Pakistan to disburse
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Famine projected to begin any time now in northern Gaza, IPC says
More than half the population of Gaza — 1.1 million people — is facing catastrophic levels of hunger, a group of international charities said, falling in the highest Phase 5 classification.