research papers on jury trial

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• Psychiatr Psychol Law
• v.25(3); 2018

What Evidence Matters to Jurors? The Prevalence and Importance of Different Homicide Trial Evidence to Mock Jurors

Kimberly schweitzer.

a Department of Criminal Justice University of Wyoming Laramie, WY, United States

Narina Nuñez

b Department of Psychology University of Wyoming Laramie, WY, United States

The present research explores how important different trial evidence is to mock jurors’ decisions. Study 1 surveys legal professionals to determine what evidence is common at homicide trials. Study 2 utilizes the list of evidence generated in Study 1 to ask mock jurors to report how important each piece of evidence would be in deciding their verdicts. The results indicate that DNA is most important to mock jurors, followed by fingerprints, the weapon, video records, crime-scene photos, gunshot residue, bodily secretions, video confession, testimony from a forensic expert, and eyewitness testimony. Study 3 utilizes a different methodology wherein mock jurors were presented with folders labeled with different evidence and asked to choose the piece of evidence they wanted to learn more about first, second, and so on. The results from Study 3 indicate again that DNA evidence is most important to mock jurors, followed by video confession evidence, eyewitness testimony, and fingerprint evidence. Implications are discussed.

Although approximately 90 to 95% of criminal cases end in a plea deal, the remaining 5 to 10% of cases can end up in a jury trial (Devers, 2011 ). These cases tend to concern more serious offenses (e.g., first-degree murder) and often are not ‘slam dunk’ cases for either side. Thus, the criminal justice system relies on jurors to be the fact-finders and determine the guilt or innocence of the defendant through listening to a variety of different types of evidence presented at a trial. A subset of the empirical literature in psychology and law has attempted to determine how important mock jurors perceive the different pieces of trial evidence to be when making their verdict decisions. This research has typically been carried out using a deductive approach informed by theory. Although deductive research is common and often warranted, the present research was conducted to determine if utilizing an inductive approach to researching jurors’ perceptions of the importance of trial evidence would lead to similar results.

Knowing which evidence jurors perceive to be most important has many benefits. First, researchers can focus their efforts on the evidence that is most important to jurors. Specifically, researchers can test and explore how different methods of presentation and different characteristics of that evidence might lead jurors to make different decisions. Thus, the literature would better reflect the needs of those wanting to apply it to the courtroom. Second, legal actors (e.g., attorneys and judges) can make more informed decisions if they know what evidence is important to jurors. For example, prosecutors and defense attorneys would know what evidence is likely to bolster or weaken their case and can adjust their strategies accordingly. Thus, knowing what evidence jurors might value has both empirical and practical applications. To provide guidance for researchers and practitioners, the present research explores how important mock jurors report different pieces of evidence to be, utilizing an inductive approach to research.

Jurors’ Weighting of Evidence

To explore how jurors may weight specific pieces of evidence in their verdict decisions, the existing literature on the impact of three broad types of evidence on jurors’ verdicts is reviewed briefly (i.e., eyewitness testimony, expert testimony, and visual evidence).

Eyewitness Testimony

Research on eyewitness testimony is abundant and has been ongoing for more than 30 years. Although eyewitness testimony is arguably the most convincing evidence presented at trial, it is also one of the most unreliable pieces of evidence (e.g., Loftus & Schneider, 1987 ; Wells & Olson, 2003 ). This is a dangerous combination, illustrated by the fact that jurors believe eyewitness identifications to be more reliable than they actually are (Brigham & Bothwell, 1983 ). The most influential part of eyewitness testimony to jurors is the confidence of the witness (Cutler, Penrod, & Dexter, 1990 ), with increased witness confidence leading to increased perceived credibility of the witness (e.g., Wells & Lindsay, 1983 ; Whitley & Greenberg, 1986 ) and increased likelihood to convict (e.g., Cutler et al., 1990 ; Fox & Walters, 1986 ; Levett, Danielsen, Kovera, & Cutler, 2005 ; Wells, Lindsay, & Ferguson, 1979 ). Unfortunately, statistics on the prevalence of eyewitness testimony are difficult to find; however, one may infer through white papers, Supreme Court rulings, and exonerations based on fallible testimony that eyewitness testimony is common at trial.

Expert Testimony

Like eyewitness testimony, expert testimony has received attention from psycho-legal researchers, with the research regarding the impact yielding mixed findings. The various types of experts used in psycho-legal research may explain why the findings on how much weight jurors give expert testimony are varied. Using Bayes Theorem to determine the appropriate weights, some researchers have found that jurors under-weight scientific expert testimony (Faigman & Baglioni, 1988 ; Kaye & Koehler, 1991 ; Martire, Kemp, Sayle, & Newell, 2014 ; Thompson & Schumann, 1987 ), while others have found that jurors weight the testimony appropriately (Brekke, Enko, Clavet, & Seelau, 1991 ; Nuñez, Gray, & Buck, 2012 ; Saks & Wissler, 1984 ), and other researchers have found in the same study that some jurors under-weight expert testimony and others give expert testimony too much weight (B. C. Smith, Penrod, Otto, & Park, 1996 ). The broad range of the type of expert makes it difficult to draw conclusions on the degree to which jurors weight expert testimony in their final decisions. As Gross ( 1991 ) points out, there are other pieces of evidence that may play a larger role in jurors’ final decisions, such as eyewitness testimony. Presently, the majority of the research regarding the weight that jurors place on expert testimony deals specifically with psychological experts (e.g., Cutler & Kovera, 2011 ).

Research has also explored how common expert testimony is at both criminal and civil trials. The most recent exploration of the prevalence of expert testimony at trial found that in civil cases in 2012 in Polk County, IA, 86% of cases had at least one expert testify (Jurs, 2016 ). The next most recent research found similar numbers: in civil cases randomly selected to be a part of the Arizona Jury Project in 1996/7, 86% contained expert testimony (Diamond, 2007 ). However, the prevalence of expert testimony has been shown to differ based on city. In both civil and criminal cases in 1990 and 1991, experts were present in 92% of cases in Baltimore, MD, 46% of cases in Seattle, WA, and 80% of cases in Tuscon, AZ (Shuman, Whitaker, & Champagne, 1994 ). Two years prior (1988), research indicated that 63% of civil cases in Dallas, TX, contained expert testimony. Thus, it seems that not only has the prevalence of expert testimony increased over time, but also that prevalence varies according to city and state. Unfortunately, much of the existing research does not further break down the prevalence of expert testimony by type of expert, although Diamond ( 2007 ) reports that the experts included physicians, mental health professionals, biomechanical engineers, financial analysts, and academic scientists (frequencies of each are not given).

Visual Evidence

A third type of evidence, visual evidence, has long been used to supplement the testimony of experts and eyewitnesses (Mnookin, 1998 ), and has become increasingly common as technology has advanced (Feigenson & Spiesel, 2009 ). As the prevalence of photographs, videos, and maps has increased, so too has the concern regarding their influence on jurors (Bornstein, Miller, Nemeth, Page, & Musil, 2005 ). Much of the psycho-legal literature has focused on the effect of gruesome crime-scene pictures on jurors’ decisions. For example, Bright and Goodman-Delahunty ( 2006 ) presented participants with gruesome crime-scene pictures, neutral pictures, or no pictures and examined how the pictures affected verdicts. It was found that the mock jurors who were shown pictures, whether gruesome or not, were more likely to find the defendant guilty than those who were not shown any pictures (Bright & Goodman-Delahunty, 2006 ). Finkelstein and Bastounis ( 2010 ) examined the effects of a crime-scene photograph on mock jurors’ sentencing recommendations. The participants read a trial transcript depicting an involuntary homicide and half were shown a photograph of the bloody victim at the crime scene. The participants were then asked to sentence the defendant (who had already been found guilty) to up to 15 years in prison. The participants who were shown the photograph of the crime scene gave significantly longer sentences than those who did not see the photograph (Finkelstein & Bastounis, 2010 ). These findings and others indicate that visual evidence, particularly when it is gruesome, leads to more punitive decisions (e.g., Bright & Goodman-Delahunty, 2006 ; Finkelstein & Bastounis, 2010 ; Oliver & Griffitt, 1976 ; Whalen & Blanchard, 1982 ).

The Present Research

The present research was designed to extend the current literature regarding the prevalence and importance of trial evidence (e.g., eyewitness testimony, expert testimony and visual evidence) by first determining what types of evidence are commonly presented to jurors during trial. As the literature on the prevalence of expert testimony indicates, factors such as the location of the court can impact prevalence statistics. Thus, the present research surveyed legal professionals from various locations in the United States in order to obtain a more diverse perspective. Second, the present research seeks to explore how important mock jurors view the prevalent evidence to be. The evidence presented at any given trial is case-type specific, so a decision was made to examine homicide trials because of the frequency at which homicides occur; homicide was the most severe offense in the 75 largest counties in the United States for 60% of the defendants arrested for more than one felony in 2009, second only to rape (65%; Reaves, 2013 ).

Study 1 was conducted to determine what evidence is commonly presented at homicide trials by surveying a sample of legal professionals (e.g., lawyers and judges). Study 2 and Study 3 were designed to explore how important this evidence is to mock jurors using two different methodologies. Because this research is exploratory and uses an inductive approach, specific hypotheses were not warranted. Overall, the goal was to determine what evidence, when given a list of common homicide trial evidence, mock jurors would find important to the process of reaching a verdict in a homicide trial.

The purpose of Study 1 is to determine what evidence legal professionals report as being commonly presented at homicide trials. Presently, there is only one published study that explores what evidence is presented at trial, although it is specific to civil trials and expert testimony, and is based on 30-year-old trial data (Gross, 1991 ). Additionally, there are no field studies to the authors’ knowledge that explore the frequency of a variety of different pieces/types of evidence at criminal homicide trials. As such, Study 1 is necessary in order to obtain some sort of empirically supported list of evidence that is commonly presented at homicide trials to utilize in future studies.

Participants and Design

Attorneys and judges ( n = 136) from six states (CA, CO, IA, MI, TX, and WI) in the United States participated in the current study. The states recruited from were chosen after a search of online legal professional databases was conducted across the country. This search yielded five states (CA, CO, IA, MI, and WI) which had emails for criminal attorneys (both public and private) and judges listed on their respective websites. Contact information for attorneys and judges from the sixth state, TX, was obtained from another research group that had generated an email list for a previous study utilizing legal professionals. These states provide a representative range in the sentencing guidelines for homicide (i.e., first- or second-degree murder) from a minimum of 25 years to a maximum of either life in prison without the possibility of parole or the death penalty. Further, the chosen states also provide a balanced representation of political beliefs, with two states being traditionally liberal (CA and CO), three states being traditionally conservative (TX, WI, and MI), and one state being traditionally split (IA).

Potential participants ( n = 3098) were then contacted via email, briefly told the purpose of the study, and provided with a link to participate. The participants did not receive compensation for their time, but instead were offered to be sent the findings of the study if desired. Approximately 4% ( n = 136) of the legal professionals who were contacted completed the survey. Of those, the majority of participants were male (76%) and had been practicing law for an average of 26 years, with 66% of the sample being criminal defense attorneys.

Materials and Procedure

Interested legal professionals were instructed to click on the study link provided to them at the bottom of the email solicitation they received. They were then taken to the study website and presented with informed consent documentation. Those who did not consent to participate were redirected to a thank you page and were not presented with any study materials. Those who consented to participate then proceeded through the study. Participants were first asked their gender, what type of legal professional they were, how many years they had been practicing, in what state they currently practiced, and if they had ever worked on a homicide case. Participants were then given a list of 66 pieces of evidence generated by a group of psycho-legal researchers and informed by existing literature, and a database of capital murder trial transcripts. From this list, the participants were asked to report whether they thought each piece of evidence was commonly presented at homicide trials, as well as whether or not each piece of evidence was presented at the last homicide trial they were a part of. Participants were asked if the evidence was present at their last trial to ensure they were not suffering from availability or representativeness heuristics. Participants were shown the list of 66 pieces of evidence in four separate groups (i.e., physical/biological, documentary, demonstrative, and testimony).

Lastly, participants were asked if there were any pieces of evidence they thought should have been included as part of the list of evidence presented, to account for the possibility that the list is not exhaustive. Responses to this question varied greatly; thus, no new pieces of evidence were added to the original list.

To determine whether or not availability heuristics were at play, differences between ‘common’ and ‘last’ selections were explored and found to be non-significant. Table 1 lists the 66 pieces of evidence from most common to least common based on the legal professionals’ percentages of endorsement as common. The following 10 pieces of evidence were selected as commonly presented at homicide trials by over 50% of the legal actors surveyed: crime-scene pictures, witness to the crime, diagrams of injuries, police officer expert testimony, forensic expert testimony, weapon, fingerprints, maps, audio confession, and video confession. See Table 1 for the additional evidence and the percent of endorsement associated with each piece of evidence.

Common homicide trial evidence according to attorneys (Study 1), average importance of evidence according to mTurk participants (Study 2), and the difference between the two.

There are some pieces of evidence that legal professionals reported as commonly appearing at criminal homicide trials (e.g., eyewitnesses) which have received research attention from psycho-legal researchers (for a review, see Wells & Olson, 2003 ). However, there are other pieces of evidence that the legal experts listed as commonly appearing at homicide trials which have received little scrutiny (e.g., diagrams of injuries), as well as pieces of evidence which have received substantial attention from researchers (e.g., psychological expert testimony) that the legal professionals said are not commonly presented at homicide trials. Thus, future research may focus on some of the under-studied pieces of evidence to determine if and how they affect jurors’ decisions. The main purpose of Study 1, however, was to generate a list of evidence that legal professionals reported as frequently appearing in homicide trials. This list was then utilized as the basis for Study 2 and Study 3.

The purpose of Study 2 is to determine how important mock jurors think the evidence from Study 1 is in determining their verdicts. As reviewed earlier, the literature suggests that certain types of evidence are more important to mock jurors than others. For example, research has shown that when a witness expresses confidence in his or her identification of the defendant, mock jurors are more likely to find the defendant guilty (e.g., Cutler et al., 1990 ; Levett et al., 2005 ). Furthermore, photographs have also been shown to impact mock jurors’ decisions, suggesting that mock jurors place greater weight on photographic evidence than on verbal evidence (e.g., Bright & Goodman-Delahunty, 2006 ). Expert testimony, however, has not been consistently shown to influence mock jurors’ decisions. Thus, more research is necessary to determine the role of expert testimony at trial. Study 2 is designed to further explore the perceived importance of a large variety of evidence to mock jurors, beyond eyewitness, expert, and visual evidence. A second goal of Study 2 is to narrow down the list of pieces of evidence that at least 20% of the sample said were commonly presented at homicide trials from Study 1 (41 pieces) to 10 pieces of evidence that mock jurors reported as being most important in making verdict decisions.

Participants

The participants ( n = 317) were recruited through Amazon's Mechanical Turk (mTurk) and compensated for their time through mTurk. Participants who were not United States citizens ( n = 8), who did not identify as living in the United States ( n = 5), or who failed an attention check question (i.e., ‘Please select four for this question’, n = 8) were excluded from analyses, leaving data from 296 participants, of which 175 (59.1%) were male and 234 (79.1%) were Caucasian, ranging in age from 18 to 67 years ( M = 34.78).

After consenting to participate, the participants were told to imagine they were serving on a jury whose duty it was to decide whether or not the defendant was guilty of homicide. The participants were instructed that they would be presented with 41 pieces of evidence (derived from Study 1; see Table 1 ) and asked to rate how important each piece would be in reaching a verdict. Each piece of evidence was presented without context. For example, participants were asked to rate how important DNA evidence would be when making a verdict decision and were not told whose DNA it was or where it was found. Participants were told to think about each piece of evidence as though it was the only evidence presented at trial. This was done to attempt to gain ratings of each piece of evidence independent of the other pieces. Participants were then presented with the evidence in a randomized order and asked to rate the level of importance of each using a 10-point Likert scale (where 1 = not at all important to 10 = very important ). When participants finished rating the evidence, they completed a basic demographic questionnaire and received a code to obtain compensation through mTurk.

All 41 pieces of evidence have mean scores at or above the midpoint of the scale (i.e., 5.5), indicating that each piece of evidence was on average perceived as somewhat important by mock jurors in making their verdict decisions (see Table 1 ). Although the mean rating of importance for each piece of evidence is high, there is no indication of ceiling effects; the entire range of the scale was used for all but 8 items. The results indicate that the 10 pieces of evidence mock jurors reported would be most important when deciding a verdict are (in order of importance): (1) DNA, (2) fingerprints, (3) weapon, (4) video records, (5) crime-scene photos, (6) gunshot residue, (7) other bodily secretions, (8) video confession, (9) forensic expert testimony, and (10) eyewitness testimony (see Table 2 for descriptive statistics). A comparison of the findings of Study 1 and Study 2 is presented in Table 1 .

Study 2 descriptive statistics.

The purpose of Study 2 was to obtain ratings of importance of a list of evidence that at least 20% of legal actors said are commonly presented at homicide trials. The results indicate that, on average, the jurors viewed all of the pieces of evidence to be at least somewhat important in order to reach a verdict. However, there are at least 10 pieces of evidence that the jurors rated as highly important, including some types of evidence that psycho-legal researchers have been researching (e.g., expert testimony, eyewitness testimony, and photographic evidence) and others that have received less attention (e.g., video records).

DNA evidence, which mock jurors in this study rated on average as most important when deciding a verdict (and which 49% of legal actors said is common at homicide trial), has more recently received attention from researchers (e.g., L. Smith & Bull, 2014 ; Walsh, Ribaux, Buckleton, Ross, & Roux, 2004 ). Unfortunately, like eyewitness testimony, research has found that jurors have trouble understanding the fallibility of DNA evidence, especially when conveyed in statistical terms (Findlay & Grix, 2003 ; Lieberman, Carrell, Miethe, & Krauss, 2008 ; Villejoubert & Mandel, 2002 ). In fact, Koehler ( 1996 ) found that even when mock jurors were presented with the exact same DNA evidence expressed in different notations (frequency, likelihood ratio, or posterior odds ratio), they weighted the testimony differently in their verdict decisions. Other empirical research has found that compared to Bayes Theorem, jurors over-weight (Koehler, Chia, & Lindsey, 1995 ) and under-weight (Nance & Morris, 2005 ; Schklar & Diamond, 1999 ) DNA evidence. Additionally, Lieberman et al. ( 2008 ) found that DNA evidence is the most persuasive type of evidence in determining the suspect's guilt, and is found to be even more persuasive than eyewitness testimony. This subset of research concerning DNA evidence illustrates the lack of agreement regarding the role DNA plays in jurors’ verdict decisions, further illustrating the need for more research on the topic.

The list of the 10 most important pieces of evidence as rated by the mock jurors that was obtained from Study 2 was utilized for Study 3, which was designed to partially replicate the findings from Study 2 using a different methodology. Specifically, the goal of Study 3 is to determine if having only the 10 most important pieces of evidence from Study 2 to choose from would alter mock jurors’ perceptions of importance, or if the results would remain the same as those of Study 2. However, Study 3 was designed to explore jurors’ perceptions of importance by measuring importance in a different way. The methodology utilized in Study 3 allowed the mock jurors to choose how they wanted to progress through the evidence at trial. It was realized that jurors in actual trials cannot choose what evidence they receive and the order in which they receive it, but this methodology made it possible to see how jurors might prioritize different kinds of evidence in in order to make their decision. This methodology, called a process-tracing method (for a review, see Schulte-Mecklenbeck et al., 2017 ), reveals how people collect information before making a decision, and has been used to study various aspects of decision-making (e.g., political decisions, Redlawsk, 2002 ).

Because mock jurors were allowed to choose the order in which they saw the pieces of evidence and because there were 10 pieces of evidence available, there are over 3 million possible orders. To minimize the number of different orders, a pilot test was completed first with the 10 pieces of evidence from Study 2 to see if a consistent order emerged, with the goal of narrowing the number of items down to 4 or 5.

MTurk participants ( n = 96) were presented with brief juror instructions and asked to choose from 10 folders (DNA, Fingerprints, Weapon Involved in the Crime, Video Records, Photographs of the Crime Scene, Gunshot Residue, Other Bodily Secretions, Video Confessions, Forensic Expert's Testimony, and Witness to the Crime) the evidence that they wanted to learn more about first, second, and so on. After viewing the evidence, participants were asked to decide if the defendant was guilty of homicide.

Exactly 50% of the sample chose to view 5 or more pieces of evidence (of the 10 available), with 14.6% viewing all 10 pieces and 15.6% viewing 9 pieces. An examination of the mean ranking of each piece of evidence yielded 5 pieces that were on average viewed within the first 7 pieces of evidence chosen. The 5 pieces of evidence that are ranked highest, and therefore chosen on average first, are DNA ( M = 6.08, SE = 0.41), eyewitness testimony ( M = 5.09, SE = 0.41), fingerprints ( M = 4.79, SE = 0.41), video confession ( M = 4.44, SE = 0.40), and forensic expert testimony ( M = 4.12, SE = 0.38).

For Study 3 it was necessary to determine whether or not there were reliable differences amongst the top 4 or 5 pieces of evidence; 4 pieces allowed for 24 possible orders, whereas 5 pieces allowed for 120 possible orders. The data indicate that the most important piece of evidence across both Study 2 and the pilot study (DNA) is significantly different to the fifth ranked piece of evidence (forensic expert testimony), t (95) = 4.31, p < .001. For this reason, and the large difference in the number of possible order combinations (96) between using 4 and 5 pieces of evidence, Study 3 was conducted using the top 4 pieces of evidence from the present pilot study.

The participants ( n = 123) were recruited through mTurk and compensated for their time. Participants who were not United States citizens ( n = 2), who did not identify as living in the United States ( n = 4), or who failed an attention check question ( n = 3) were excluded from analyses, leaving data from 114 participants, of which 54 (47.4%) were male and 89 (78.1%) were Caucasian, with an age range of 20 to 77 years ( M = 35.37).

After consenting to participate, the participants were asked to assume the role of mock jurors in a homicide trial in which their job was to decide whether or not the defendant was guilty of homicide. The participants were first presented with brief juror instructions and then directed to another page on which the following instructions appeared:

The defendant in this case is on trial for homicide. The folders below contain information (if available) about the specific piece of evidence typed on each folder. Please select from the folders below which piece of evidence you would like to learn more about in the order of importance. For example, if you think Evidence ‘X’ is most important to making your decision, please select that folder first, and so on, until you have viewed all of the evidence. You may only choose one folder at a time, and you can open the same folder more than once, but you are asked to look at every folder. Your goal is to determine whether or not the defendant is guilty of homicide.

Below these instructions were four folders, and the location and order of each folder on the screen was randomized. Each folder was labeled with a different piece of evidence (DNA, Fingerprints, Video Confessions, and Witness to the Crime). After participants chose which piece they wanted to learn more about first, they were directed to another page in which they were given a brief description of the evidence. For example, if participants selected to learn more about DNA evidence first, they were directed to a page where they were told: ‘The defendant's DNA was a match to the DNA found at the scene of the crime’. Each description of the evidence implied guilt. This was done in order to minimize the complexity of the design and therefore increase power. If the culpability of the evidence had also been varied, there would have been 48 possible different orders.

If participants had not viewed all four pieces of evidence, they were redirected back to the page where the evidence folders were. When all four pieces of evidence had been viewed (or participants opted to give their verdicts), participants were asked to decide whether or not the defendant was guilty of homicide. Because the evidence was all indicative of guilt, it was expected that the majority of participants would find the defendant guilty. The participants then responded to several demographic questions and were compensated for their participation.

To test the order in which participants chose to progress through the evidence, the data were coded to indicate order of progression in line with Peters ( 2013 ). The piece of evidence that mock jurors chose to view first was coded as four, the second piece was coded as three, the third piece as two, and the fourth piece as one. Items that were not chosen to be viewed were coded as zero. An examination of the mean ranking for each piece of evidence indicates that, again, DNA evidence was most likely to be viewed first ( M = 2.95, SE = 0.11), then video confession evidence ( M = 2.46, SE = 0.11), eyewitness evidence ( M = 2.33, SE = 0.10), and fingerprint evidence ( M = 2.18, SE = 0.10). DNA evidence was on average more likely to be chosen first compared to video confession, eyewitness, and fingerprint evidence, with 46.49% of mock jurors viewing DNA evidence first. However, video confession, eyewitness, and fingerprint evidence were not found to be reliably different from each other in terms of rank and order ( p s > .05). Because of this, a different form of analysis was used to further explore the order in which mock jurors progressed through the evidence.

Using the statistical program R, four decision trees were created to examine the relationship between the different types of evidence. Decision trees iteratively split the variables of interest into different groups until a homogenous group is found. The base of the decision tree is referred to as the root and is the variable that best separates the data based on the dependent variable (DV). If the split at the root does not lead to two homogeneous groups, that node is then split again, with each group generated from the split referred to as a leaf. Splitting continues until the leaves furthest from the root are homogenous or the groups are too small. Decision trees allow for paths to be generated to show what happens when variables are split certain ways. Because the goal of a decision tree is to show the path to different categories, it is necessary to define the DV. Although mock jurors were asked to give a verdict, there was little variability in responses as all of the evidence was indicative of guilt; 88.6% of participants said the defendant was guilty. Therefore, instead of using the verdict as the DV, different decision trees were created with each piece of evidence serving as the DV.

Because the mock jurors in this study were significantly more likely to choose DNA evidence first, the decision tree in which the DNA evidence is the root was determined to be the most plausible decision tree ( Figure 1 ). The decision tree that begins with DNA evidence was created when eyewitness evidence was forced to be the DV. As can be seen in Figure 1 , the tree shows that when mock jurors viewed the DNA evidence first, 66% of them then viewed video confession evidence, then fingerprint evidence, and lastly eyewitness evidence. When mock jurors viewed DNA evidence third, fourth, or not at all ( M rank < 2.5), 34% of them viewed the eyewitness evidence next. The tree also shows that there are two paths that lead to eyewitness testimony being chosen approximately third ( M rank = 2.4): through video confession or fingerprint evidence. Because eyewitness evidence was set as the DV, it was forced to be last and therefore could not come before fingerprint evidence (or DNA or video confession evidence). Disregarding the fact that eyewitness testimony was forced to be the DV, the reported decision tree analysis indicates that participants progressed through the evidence in the following order: (1) DNA, (2) video confession, (3) fingerprint, and (4) eyewitness.

Study 3 decision tree analysis with eyewitness evidence as the dependent variable.

Data from Study 3 were analyzed using two different methodologies and found to tell somewhat similar stories. Specifically, both analyses indicate that on average DNA evidence was chosen first by mock jurors and video confession evidence was chosen second. The results are less clear when considering what pieces of evidence were chosen third and fourth. When looking at mean rankings, eyewitness testimony was chosen earlier than fingerprint evidence. However, the decision tree analyses indicate that fingerprint evidence may have been chosen before eyewitness testimony. This finding must be interpreted with caution, however, as eyewitness evidence was forced to be last in order for DNA evidence to be first. These results indicate that DNA evidence is the piece of evidence that mock jurors on average want to learn more about first at a homicide trial. Thus, DNA may be the most important piece of evidence to mock jurors when deciding a verdict, as the majority of the participants in the present study selected to learn more about DNA evidence first. In a similar manner, it may be argued that a video confession is the second most important piece of evidence to mock jurors deciding the fate of a defendant on trial for homicide, as mock jurors on average chose to learn more about video confession evidence second. Likewise, eyewitness and fingerprint evidence appear to be the third and fourth most important pieces of evidence to mock jurors.

General Discussion

The present research examined first what evidence legal professionals reported to be common evidence at homicide trials, and then how important that evidence is to mock jurors when making verdict decisions. Using an inductive approach in which each study was built using the results of the previous one, the present series of studies is able to explore the importance of different evidence in deciding a verdict using a novel approach in Study 3. After surveying legal professionals and determining which evidence appears at homicide trials in Study 1, the generated list of evidence was used in Study 2. Across three studies (i.e., Study 2, the Study 3 Pilot, and Study 3) and two different methodologies, the results indicate that the mock jurors perceived DNA evidence to be most important piece of evidence when determining a verdict. The order of importance of the other pieces of evidence is, however, not consistent across the studies. Specifically, fingerprint evidence is ranked 2nd of 41 pieces in Study 2, 3rd of 10 pieces in the pilot study, and 3rd/4th of 4 pieces in Study 3; video confession evidence is ranked 8th of 41 pieces in Study 2, 4th of 10 pieces in the pilot study, and 2nd of 4 pieces in Study 3; and eyewitness testimony is ranked 10th of 41 pieces in Study 2, 2nd of 10 pieces in the pilot study, and 3rd/4th of four in Study 3.

Although the differences are not major, the following may explain the discrepancies. First, the differences may be due to the decrease in total evidence in each progressive study. Specifically, Study 2 involved 41 pieces of evidence, the pilot study involved 10 pieces, and Study 3 involved just 4 pieces. Differing numbers of evidence may lead to different types of comparisons, and thus to different importance levels. For example, eyewitness testimony may not have seemed as important when considered with 40 other pieces of evidence, but when in the context of 10 or less pieces of evidence, it may have seemed more important. Further, Study 2 is the only study in which mock jurors were asked to consider each piece of evidence as the only piece of evidence present at trial. In the proceeding studies, mock jurors were aware that there were 4 to 10 pieces of evidence for them to consider, and it is likely that they considered the evidence as a whole, instead of individually. Additionally, Study 2 and Study 3 differ in methodology; instead of asking mock jurors to rate the importance of each piece of evidence, as was done in Study 2, Study 3 asked mocked jurors to choose the evidence they wanted to learn more about first, second, and so on based on how important they perceived each piece of evidence to be. This novel methodology made it possible to obtain a measure of importance without asking mock jurors to quantify how important each piece of evidence was.

Although inconsistent in the exact order, the results do indicate that DNA, fingerprints, eyewitness testimony, and video confession evidence are important to mock jurors. As such, it seems important that future psycho-legal research should explore what it is about these pieces of evidence that causes them to be perceived as important, and if there are any factors that may alter their importance. This research can then better inform policy and legal professionals.

Limitations

The present series of studies is limited by the fact that the scenarios are specific to, and the evidence comes from, a homicide trial. However, this was done purposefully because it cannot be assumed that all types of evidence will be perceived similarly by jurors across case types (e.g., homicide versus drug trafficking). The present research is also in part limited by the small subset of evidence that was used in Study 3. Unfortunately, this was a requirement of the design to be able to obtain the required sample size. As mentioned earlier, the difference in the number of possible orders in Study 3 when going from 5 to 4 pieces of evidence is 96 (120 versus 24). These drastic differences encourage the use of fewer pieces of evidence. Nevertheless, the variation of the 4 pieces of evidence was still more than what is typical in the psycho-legal research. Design restrictions also did not allow the present research to be able to explore the importance of exculpatory evidence. Future research should examine how important mock jurors perceive exonerating evidence, or lack of important evidence, to be in making verdict decisions. It may be the case that DNA evidence is equally important to mock jurors whether or not it is present and damning. In other words, jurors may say a defendant is guilty if the DNA evidence is a match to the defendant, not guilty if the DNA is not a match, and not guilty if there is no DNA evidence. However, future research should test this.

Although the design of the present research utilizes an inductive approach and novel methodology, there may be an alternative explanation for the findings. Study 2 and Study 3 asked participants to indicate the importance of various pieces of evidence. However, the possibility that participants’ prior knowledge of the evidence was influential in their decisions cannot be ruled out. For example, participants may have thought that DNA evidence was important, but they may also have known very little about it and chosen it first because they wanted to learn more about it. Thus, their choice of DNA evidence first may not have indicated that it was more important than video confession evidence. Alternatively, in Study 2, participants may have reported certain types of evidence as less important (e.g., neuroimages) because of their unfamiliarity with the nature of the evidence itself or how it can be utilized in a criminal trial. Thus, their lower rating of importance of a piece of evidence may indicate their lack of knowledge as opposed to unimportance in verdict decisions. Future research should explore the possibility that prior knowledge of evidence may influence interpretations of importance.

Lastly, future research should conduct an analysis of the evidence presented at actual criminal homicide trials. Study 1 was designed to begin to learn about what evidence is common, but unfortunately there is no fieldwork indicating that the present results are indicative of actual trial evidence. Until a comprehensive and representative field study is conducted, the present research is the best proxy for a list of common homicide trial evidence.

Conclusions

The present research establishes the types of evidence that legal professionals indicate are commonly presented at trial, and explores which of these types are considered by mock jurors to be important. The results obtained expand the existing knowledge of how jurors make decisions during trial by starting with evidence that legal professionals report to be commonly presented at trial and using that evidence to determine what types of evidence are important to mock jurors when making verdict decisions. Four pieces of evidence were found to be most important in a homicide trial: DNA, fingerprint, video confession, and eyewitness evidence. Using more elaborate trial materials, researchers should examine how these four pieces (or the lack of these crucial pieces) can affect trial outcomes. More knowledge regarding the ways in which nuances in common trial evidence can affect verdicts can inform courtroom procedures and policy.

Disclosure Statement

No potential conflict of interest was reported by the authors.

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41 Jury Decision-Making

Lora M. Levett, University of Florida

• Published: 23 February 2023
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The US Constitution guarantees the right to a public trial by an impartial jury of one’s peers in both criminal and civil contexts. This system is a cornerstone of our democracy but is not free from criticism. Researchers have spent decades investigating the jury, exploring what affects jurors’ decisions, and how to increase the competence of this decision-making body. In this broad overview, the chapter first explores the theoretical underpinnings of juror and jury decision-making and discusses mathematical and explanation-based models at the juror and jury levels. Next, the chapter explores factors that influence the jury’s decision, including the demographic and attitudinal characteristics of the legal participants, examples of evidentiary, extra-evidentiary, and trial factors, including the possibility of judges as alternative decision makers. Last, I summarize directions for future research and discuss some of the methodological difficulties jury researchers may encounter.

Jury trials exist in a paradox in our American society ( Bornstein & Greene, 2017 ). First, juries are considered central to the American democratic society (see Abramson, 1994 ). In the United States, the Sixth Amendment to the US Constitution guarantees the right to a “speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed,” and the Seventh Amendment guarantees the same right to a trial by jury for civil litigants. Thus, the jury places the execution of the law in the hands of the governed, with citizens assuming the responsibility of fact-finding, interpreting and applying the law, and rendering a decision that injects the community’s sentiment and reinforces the notion that the community desires that the law be enforced. The jury serves as a protection against arbitrary rule ( Abramson, 1994 ). It ensures that legal decisions reflect communities’ sentiments of commonsense justice (Finkel, 1995) , and increases civic engagement, satisfaction with the legal system, and perceptions of legitimacy of the criminal justice system ( Gastil et al., 2002 ).

Simultaneously, critics have questioned the jury’s ability to execute these weighty tasks (see Bornstein & Greene, 2017 , for a review). These criticisms, some of which are exaggerations or “jury myths” and others that are well founded but have potential to be corrected through reforms to trial procedure, coexist with the idea that the jury is a cornerstone for a democratic system ( Bornstein & Greene, 2017 ; Diamond, 2003 ). This paradox leads to several empirical questions about jury behavior. What influences the jury’s decision? Do the factors that should legally influence the jury’s decision do so? How might we improve the jury’s decision?

Given the breadth of research in the area of jury decision-making, a full review of all possible areas is not feasible given the constraints of the chapter. However, the reader will find that other chapters in this volume address issues of juror and jury decision-making as they relate to the topic (see Hunt , on issues related to race; Peter-Hagene et al. , on issues related to emotion; and Cutler & Krauss , on issues related to expert testimony, this volume). Here, I explore the broad literature in juror and jury decision-making with the first goal of understanding the overall theory behind how the jury makes decisions. Next, I explore the factors that influence decision-making. Last, I discuss implications of this work and directions for future research.

Theoretical Underpinnings

Jury scholars have engaged in substantial scholarship to provide a theoretical explanation of how jurors and juries make their decisions. This work generally integrates principles from social and cognitive psychology into the unique task given to juries at trial to create a model describing the decision-making process.

Models of Juror Decision-Making:

Current models typically vary on two dimensions—the method of modeling the decision (mathematical vs. explanation based) and the level of decision (individual vs. the group).

Mathematical Models

At the juror level, researchers using mathematical models of juror decision-making use formal equations to represent the juror’s decision process. Generally, these models assume that jurors render decisions using a single “mental meter,” or the cognitive representation of the jurors’ belief that in all probability, the defendant committed the act in question ( Hastie, 1993 ). At the beginning of trial, jurors start with a belief somewhere along the mental meter based on their values, preconceptions about the case, and the judge’s instructions.

To update the mental meter throughout trial, jurors processing trial evidence identify probative pieces of information from that evidence. They then assign weight to that evidence and combine that weight with the previous value of the mental meter to update to a new belief in the defendant’s guilt. At the end of the trial, jurors listen to jury instructions and use a combination of the jury instructions, severity of the crime, and personal attitudes and beliefs to create a threshold for conviction. They then compare the final value of the mental meter with their threshold for conviction to render a verdict. If the probability of the meter exceeds the threshold for conviction, the juror convicts; if not, the juror acquits ( Hastie, 1993 ).

The most popular mathematical models are the algebraic, stochastic process, and Bayesian models ( Hastie, 1993 ). Given the scope of this chapter, a full discussion of the nuances of these models is not possible (for a thorough review, see Devine, 2012 ). Generally, models differ in the mathematical formula used to weight evidence (e.g., an additive model vs. probability theory–based multiplicative model; Hastie, 1993 ), whether and how the mental meter freezes, and whether the outcome is a single value or a range of values to account for individual differences.

Research has shown mixed support for the mathematical models generally ( Groscup & Tallon, 2009 ). In one study, researchers found the averaging model tested better fit the jurors’ decisions than the additive model ( Moore & Gump, 1995 ). A different study showed jurors tended to underutilize the probabilistic evidence compared to the Bayesian norms ( Smith et al., 1996 ). The biggest critique of mathematical models is that they largely simplify the complicated and nuanced decision-making process ( Hastie, 1993 ). Explanation-based models attempt to better account for this multifaceted process.

The Story Model

In explanation-based models, jurors use available information to create cause-and-effect explanations and then make subsequent decisions based on those explanations ( Groscup & Tallon, 2009 ). These models account for the jurors’ active role in the decision-making process, piecing together and making inferences about evidence. The most empirically supported model is the Story Model for Juror Decision-Making (Pennington & Hastie, 1988 , 1993 ). According to the Story Model, jurors create a narrative to account for the trial evidence, incorporating their own perceptions and unique experiences into the narrative. This takes place in a sequence of three steps: story construction, learning verdict options, and story mapping.

In story construction, Jurors create multiple stories or narratives as they listen to trial evidence (Pennington & Hastie, 1993 ). In creating the narrative, jurors incorporate their own personal knowledge and experiences and their knowledge about what makes a complete story to fill in the blanks left by evidence. Typically, one story emerges as the best story resulting from three factors termed certainty principles: coverage, coherence, and uniqueness (Pennington & Hastie, 1993 ). A story’s coverage depends on the amount of trial evidence it explains. A coherent story is plausible, complete, and consistent. If more than one study is high in both coverage and coherence, the lack of uniqueness would make either story less likely to be believed.

After determining which story is best, jurors learn the verdict options available to them through judicial instructions (Pennington & Hastie, 1993 ). This is a tough task given the difficulty jurors have in comprehending judicial instructions and often have preconceived notions about crime, law, or legal situations that interfere with their ability to learn the legal definitions in judicial instructions ( Smith, 1991 ). After learning verdict options, jurors map their chosen story onto the possible options and determine the best match (Pennington & Hastie, 1993 ). If the best story favors a prosecution verdict, jurors determine whether their confidence in the story (determined by certainty factors) exceeds the threshold required for a guilty verdict (determined by judicial instructions and perceptions of the standard of proof). If no story matches an available verdict option or confidence is low, the juror renders a not guilty verdict.

Overall, research has shown support for the Story Model (e.g., Behl et al., 2013 ; Huntley & Costanzo, 2003 ; Pennington & Hastie, 1988 ). In two studies, stories jurors created mediated the relationship between evidence and verdict ( Behl et al., 2013 ; Huntley & Costanzo, 2003 ). However, despite the comprehensiveness of the Story Model in accounting for the juror’s decision-making process, it does not explain how jurors’ stories may change or combine as a result of the deliberation process. Ultimately, jurors need to unanimously agree to render a verdict. 1 Similar to examining juror decision-making, jury researchers have used social and cognitive psychological methods to model the jury’s decision.

Models of Jury Decision-Making:

Mirroring work modeling individual jurors’ decisions, models of jury decision-making fall into the broad categories of mathematical and explanation-based theories.

Mathematical Models.

The verdict distribution of jurors’ individual verdict preferences prior to deliberation is the best predictor of the jury’s verdict ( Devine et al., 2001 ). As such, most work examining jury deliberation uses mathematical modeling, predicting the final jury verdict based on this distribution. Like individual mathematical models, these models vary in the formula or methodology used to combine the verdict preferences into a final verdict (for a full review, see Devine, 2012 ). One of the most popular models is the Social Decision Scheme (SDS) model ( Davis, 1973 ).

In the SDS model, the initial distribution of jurors’ possible predeliberation preferences is modeled in a matrix representing guilty and not guilty verdicts, which are then combined into a final verdict. Several studies have shown that if two-thirds or more of a jury go into deliberation in agreement on a particular verdict, that verdict will likely be the final decision ( Stasser et al., 1989 ). However, the majorities that are most likely to be successful are those that favor a not guilty verdict—especially in cases in which the jury is more divided at the onset of deliberation ( Devine et al., 2001 ; MacCoun & Kerr, 1988 ).

Like individual models, criticisms of the group mathematical models include that they do not account for the complex process of deliberation. For example, one study showed that adding deliberation variables to the mathematical model almost doubled the amount of variance explained in the final verdict ( Hastie et al., 1998 ). Mathematical models assume that all jurors have a predeliberation verdict preference; this may not be the case ( Hanaford-Agor et al., 2002 ).

Explanation-Based Models

Given the shortcomings of group mathematical models, researchers have begun the process of integrating social psychological literature on group decision-making with the story model of juror decision-making and mathematical models to explain jury decision-making (see Levett & Devine, 2017 , for a review). In showing how the story model may apply to the group decision-making process, one deliberation study may be reframed in light of research on the story ( Holstein, 1985 ). In this study, data showed that fifteen “schematic interpretations,” or a juror’s attempt to explain what happened in the case, emerged in deliberations. These interpretations could be conceptualized as stories. Further, jurors reframed their schematic interpretations to account for other jurors’ interpretations of the evidence in deliberation, essentially adapting their own stories to create a dominant, group story. The more schematic interpretations (or stories) presented in the deliberation, the likelihood of a hung jury increased ( Holstein, 1985 ), indicating that if the stories lacked uniqueness, the likelihood of any story emerging as the dominant one decreased ( Levett & Devine, 2017 ). Of course, this study is limited by the small sample size, but it provides a starting point for how the story model might operate in the deliberation context.

Based on a systematic review of the literature, Devine (2012) proposed a multilevel theory of jury decision-making that integrates decision-making across the juror and jury levels. The first stage of the model is termed the “Director’s Cut” model, and it covers the individual juror’s process prior to deliberation ( Devine, 2012 ). This model posits that jurors put the case facts and beliefs about the case into a narrative, arranging sequences to form a “final cut” in a manner similar to how a film director creates movies ( Devine, 2012 ). It builds on the story model of juror decision-making by going into greater depth on how individual differences, interpretations of evidence, and extra-evidentiary information (reviewed later in this chapter) may influence story creation, distinguishing between story construction processes for plaintiff/prosecution stories versus defense stories, and differently evaluating the best story.

The second stage uses the output of the Director’s Cut model as input for the jury-level model, termed the “Story Sampling” model. The Story Sampling model describes the deliberation process as a collective search for the best story to describe the evidence ( Devine, 2012 ). It accounts for the characteristics of jurors in explaining variation related to participating in deliberation and the types and frequency of information relayed by jurors in deliberation. It also incorporates information on deliberation style and other group dynamic variables in describing deliberation. For example, the model incorporates principles of informational influence (i.e., when people change their mind because of an actual change in attitude) and normative influence (i.e., when people change their mind publicly to agree with the group, but privately maintain their previous attitude) ( Deutsch & Gerard, 1955 ). In sum, the model integrates literature on juror decision-making and social psychological group processes to propose an integrative, explanation-based model that comprehensively explains the jury’s decision. The model leads logically to several testable hypotheses to move our understanding of the jury’s decision forward (see Devine, 2012 , for a full discussion of those possibilities).

What Affects Jurors’ Decisions?

In addition to modeling the juror and jury decision-making process, researchers have spent decades studying the factors that influence jurors’ decisions and whether those factors are appropriate or inappropriate in their influence. Generally, these factors fall into three categories: characteristics of trial participants, evidentiary and extra-evidentiary factors, and trial factors.

Characteristics of Trial Participants:

Given the scope of this chapter, in this examination, I focus on a subset of each of the three categories, providing examples of how researchers have approached the study of how characteristics of trial participants, evidentiary and extra-evidentiary factors, and trial factors influence jurors’ decisions.

Demographic Variables

In examining how the demographic characteristics of the jurors and trial participants affect juror and jury decision-making, researchers typically examine how the demographic characteristics directly affect decision-making or moderate the effects of other variables on jurors’ decisions. These effects may vary based on the type of trial. For example, in most types of cases, juror gender does not have a strong effect on juror decision-making. However, in cases involving sexual assault or child sexual abuse, a meta-analysis showed that women were more likely than men to convict the defendant ( Schutte & Hosch, 1997 ). Similarly, women were more likely than men to interpret more types of behaviors as sexual harassment ( Rotundo et al., 2001 ).

Demographic characteristics of the defendant also may directly affect jurors’ decisions. For example, one meta-analysis synthesized studies exploring the effect of attractiveness on jurors’ judgments of guilt and sentence ( Mazzella & Feingold, 1994 ). Results demonstrated that being physically attractive was beneficial to defendants, although other variables also affected this relationship ( Mazzella & Feingold, 1994 ). Results from studies following the meta-analysis have been somewhat mixed (e.g., Gunnel & Ceci, 2010 ; see Devine, 2012 , for a review).

Other defendant characteristics also affect jurors’ perceptions and decision-making, including defendant remorse (e.g., Bornstein et al., 2002 ), criminal record (e.g., Wissler & Saks, 1985 ) and defendant socioeconomic status (SES; Mazzella & Feingold, 1994 ), and defendant race ( Mitchell et al., 2005 ). These relationships may also depend on other trial, demographic, or attitudinal variables. For example, the effect of the defendant’s prior criminal record may vary based on the content of the record compared to the current charge (see Devine, 2012 , for a review). Similarly, effects of defendant SES may change based on the combination of SES and race (e.g., Espinoza & Willis-Esqueda, 2008 ). Effects of defendant race depends on the combination of defendant and juror race (see Hunt , this volume), and may be exacerbated by systematic suppression of minorities from participating in jury duty (see Kovera, 2019 ).

Attitudinal Variables

In addition to exploring the effects of demographic characteristics on legal outcomes, researchers have also explored how jurors’ attitudes affect decision-making. First, jurors’ attitudes may affect jurors’ decision as direct effects. One meta-analysis combining twenty studies (thirty-two effects), showed a small relationship between authoritarianism and guilt, such that jurors who were higher in authoritarianism were also more conviction prone than jurors lower in authoritarianism ( Narby et al., 1993 ). Similarly, Kassin and Wrightsman (1983) developed the first version of the Juror Bias Scale (JBS), which was later revised by Lecci and Myers (2002) . The JBS measured jurors’ tendencies to favor the prosecution or defense and related to verdict. Lecci and Myers (2002) revised the factor structure of the JBS and later went on to develop the Pretrial Juror Attitude Questionnaire (PJAQ; Lecci & Myers, 2008 ). The PJAQ contained six factors (conviction proneness, cynicism toward the defense, innate criminality, racial bias, social justice, and system confidence) and accounted for variance in jurors’ judgments beyond those factors accounted for in legal authoritarianism measures or the JBS.

In addition to direct effects of attitudes on jurors’ decisions, attitudes may also affect decisions through indirect effects. For example, in one study, jurors who viewed body-worn camera footage in one case were less likely than those who did not see such footage to believe the defendant was guilty of resisting arrest; this relationship was mediated by jurors’ perceptions of moral outrage toward the officer ( Saulnier et al., 2020 ). Similarly, examining jurors’ sentences in a death penalty case showed that jurors with more fundamentalist attitudes (vs. less) were more likely to sentence the defendant to death because fundamentalism was associated with weighing aggravators more than mitigators ( Yelderman et al., 2019 ).

Beyond direct and indirect attitudinal effects, the combination of juror characteristics and attitudes may also influence outcomes. In a meta-analysis examining jurors’ decisions in child sexual abuse cases, researchers showed that mock jurors who had experienced abuse or knew someone who had been abused as a child were more empathetic toward child victims in a mock trial case than those jurors who did not have abuse experience or knowledge ( Jones et al., 2020 ). Those jurors who were more empathetic toward child victims perceived those children as more credible and therefore were more likely to find the defendant guilty.

Similarly, other studies have shown that the chance to serve on a jury may be limited because of a jurors’ attitudinal characteristics, and these attitudes may be related to demographics. For example, in examining decision-making in capital cases, jurors are required to be “death qualified” ( Haney, 1984 ). 2 That is, jurors who would not impose the death penalty because of these attitudes and/or would not be able to impartially consider the evidence knowing that a death sentence is possible are excluded from the jury.

However, the changes resulting from excluding non-death qualified jurors are not just attitudinal. A meta-analysis showed evidence that the death qualification process also changes the demographic composition of the jury, with Black jurors and female jurors more likely than White jurors and male jurors to hold death penalty attitudes that would exclude them from serving on the jury ( Filkins et al., 1998 ). Therefore, death qualified juries are generally more homogeneous in terms of attitudes and demographics, which is related to differences in the quality of decision-making. Death qualified jurors are more conviction prone than non-death qualified jurors ( Cowan et al., 1984 ; Moran & Comfort, 1986 ) and juries containing both death qualified and non-death qualified jurors made higher-quality decisions than juries containing only death qualified jurors ( Cowan et al., 1984 ).

In reviewing this research, one could note that the influence of demographic or attitudinal variables often depends on other characteristics of the case. That is, attitudes and demographics may influence outcomes, but how that information influences outcomes may vary depending on the type of evidence, extra-evidentiary information, or trial procedure.

Evidentiary Factors and Extra-Evidentiary Factors

Given that another piece of the puzzle in understanding jurors’ decisions is understanding how they will interpret and use evidence, and how factors other than the evidence may influence their interpretations, we next turn to examining jurors interpret and use this information more broadly.

Evidentiary Factors

The strongest predictor of a juror’s decision is the strength of the evidence against the defendant. That is, across experimental and field studies, variations in strength of evidence reliably affect trial outcomes ( Devine, 2012 ). However, looking beyond general measures of evidence begets more questions, especially when considering that cases with exceptionally strong or weak evidence are likely to resolve via plea agreement or withdrawing charges. Thus, cases that are heard by a jury are also the cases that may contain more equivocal evidence, necessitating the exploration of whether jurors can properly evaluate that evidence. Do jurors properly assign weight to reliable evidence and properly discount less reliable evidence? In this section, I review how jurors evaluate two types of evidence—eyewitness and confession evidence—as examples of the research conducted in this area.

Eyewitness Evidence. In the majority of wrongful conviction cases documented by the Innocence Project, at least one eyewitness made an incorrect identification of the defendant ( Innocence Project, 2021 ; see Smith & Wells , this volume). Importantly, once an identification is made, that identification must be properly evaluated for a just outcome to occur. That is, the fact-finder must recognize those conditions under which an eyewitness is more likely to be mistaken. However, to show that jurors can properly evaluate eyewitness evidence, we must test whether they can weigh identifications obtained under more ideal conditions more heavily than those obtained under less ideal conditions. Trial simulation methodologies allow for this type of test. These studies generally show that eyewitness evidence affects jurors’ decisions ( Loftus, 1980 ).

However, the evidence is mixed on whether variations in the factors that affect the quality of the identification appropriately affect jurors’ decisions. In one study, researchers manipulated system and estimator variables (see Smith & Wells , this volume, for further discussion on this distinction) known to affect eyewitness accuracy and witness confidence ( Cutler et al., 1990 ). They found that only eyewitness confidence affected jurors’ decisions. Other research has replicated these findings, with some exceptions (e.g., Devenport & Cutler, 2004 ; Devenport et al., 2002 ). In these studies, variation in lineup composition ( Devenport et al., 2002 ) and lineup composition and lineup instructions ( Devenport & Cutler, 2004 ) affected jurors’ ratings of the suggestiveness of the lineup but had limited or no effect on trial outcomes.

Thus, overall, variations in the quality of the eyewitness evidence do not reliably affect jurors’ verdicts in appropriate ways. In addition, trial mechanisms designed to improve juror comprehension of evidence (expert testimony, cross examination, voir dire, closing arguments) seem limited in their ability to educate jurors about these factors ( Bornstein & Greene, 2017 ), although training programs designed to teach jurors about factors affecting eyewitness accuracy may be more promising ( Pawlenko et al, 2013 ).

Confession Evidence. False confessions also contribute to a significant number of wrongful convictions ( Innocence Project, 2021 ). One a confession is admitted to evidence, if jurors determine that police coercion was a significant factor in obtaining the confession, the jury is responsible for weighing the confession appropriately given the conditions under which the confession was obtained. A false confession is more likely under coercive conditions (see Kassin et al., 2010 , for a review). Therefore, theoretically, confessions obtained under those conditions should be weighed less than confessions obtained under less coercive conditions.

Survey research has shown that laypeople recognize that false confessions can occur ( Chojnacki et al., 2008 ; Henkel et al., 2008 ). However, in other work, laypeople did not understand the factors leading to false confession (e.g., Blandón-Gitlin et al., 2011 ; Leo & Lui, 2009 ). Even though laypeople may believe that false confessions are possible, confession evidence is very persuasive in trial. Jurors in two studies did not weigh confession evidence differently in the presence of situational pressures to confess ( Kassin & Sukel, 1997 ; Kassin & Wrightsman, 1980 ), and the effect of confession on verdict persisted even if jurors believed the confession was involuntary and that it did not affect their verdicts ( Kassin & Sukel, 1997 ).

Recording the entirety of the interrogation and confession is a suggestion for improving jurors’ evaluations of confession evidence because it affords jurors the opportunity to fully evaluate all the aspects of the confession. The recording should be equally focused on the interrogator and suspect ( Lassiter et al., 2002 ). Videos focused solely on the suspect are more likely to result in judgments of confession voluntariness compared to videos focused equally on the suspect and interrogator. However, other factors that make the suspect salient (e.g., the suspect’s race or sexual orientation) may undermine the efficacy of the equal focus perspective ( Pickel et al., 2013 ; Ratclif et al., 2010 ).

Studies have demonstrated the promise of expert testimony for educating jurors about the quality of the confession evidence related to the content of the confession ( Henderson & Levett, 2016 ) and the coerciveness of the interrogation tactics ( Blandón-Gitlin et al., 2011 ). Conversely, educational jury instructions have not shown the same promise (e.g., Kassin & Wrightsman, 1981 ). However, this research question has not been as thoroughly tested—perhaps because judges may be more reluctant to include such instructions ( Bornstein & Greene, 2017 ).

Extra Evidentiary Factors

Some types of juror bias are inherent to the individual juror (e.g., use of stereotypes and/or attitudes that affect jurors’ decisions that should not affect their decisions). Other forms of bias in jury decision-making are induced through the situation surrounding or occurring in the trial. Here, I explore two of these factors: pretrial publicity (PTP) and inadmissible evidence.

Pretrial Publicity. PTP, or information released to the public that may unfairly influence the jury, adversely affects jurors’ decisions ( American Bar Association, 2000 ). Such information could include information about the defendant’s prior criminal record, character, inadmissible evidence, or admissible evidence that could lead the juror to infer that the defendant is guilty prior to trial. In short, PTP is any information (specific to the case or more generally related to topics in the case that could interfere with a juror’s ability to fairly evaluate evidence and presume the defendant was innocent until proven guilty ( Kovera & Levett, 2015 ).

Exposure to pro-prosecution PTP negatively affects jurors’ decisions in both field studies and laboratory simulations. In a meta-analysis examining the relationship between PTP and jurors’ decisions, researchers showed a small to medium effect of exposure to PTP on jurors’ judgments, such that exposure to pro-prosecution PTP increased the probability that jurors would convict the defendant compared to jurors who were not exposed to PTP ( Steblay et al., 1999 ). Further, this effect increased in magnitude as the ecological validity of the studies increased—those studies that closer mimicked real-world conditions had larger effects of PTP on jurors’ decisions. Conversely, pro-defense PTP has not had the same consistent effect on jurors’ decisions (see Bornstein et al., 2002 ; Ruva & McEvoy, 2008 ).

Given the strong effects of pro-prosecution PTP on jurors’ decisions, researchers have turned to examining whether modifications to trial procedures or safeguards that could help jurors attenuate the bias introduced by PTP. This research has shown that some of the proposed safeguards are more or less effective. For example, instructing the jurors to ignore the PTP does not eliminate PTP effects (e.g., Bornstein et al., 2002 ). Similarly, another suggested safeguard is extending voir dire to allow judges and attorneys to identify jurors who have been biased by PTP; however, studies have also shown this safeguard is ineffective ( Dexter et al., 1992 ). Further, in several studies, deliberation was also ineffective at attenuating bias due to PTP (Ruva & Guenther, 2015 , 2017 ), and if the PTP is emotional in nature, deliberation may actually increase the effect of pro-prosecution PTP on jurors’ decisions ( Kerr et al., 1999 ; Kramer et al., 1990 ). However, one safeguard appears to be the most effective in attenuating the effect of PTP on jurors’ decisions—a change of venue, or moving the trial to a community that has had no PTP exposure (or at least less PTP exposure). In this case, the most effective way to reduce bias is to ensure jurors have not been biased by the PTP in the first place.

Inadmissible Evidence. Similar to research on PTP, researchers have also investigated whether jurors can adequately disregard inadmissible evidence that is presented at trial. Overall, the results mirror the PTP literature. In one meta-analysis, researchers combined forty-eight studies and demonstrated that inadmissible evidence reliably effects jurors’ decisions in the direction consistent with the bias introduced by the inadmissible evidence ( Steblay et al., 2006 ). However, if judges provide a rationale for why the evidence is inadmissible, jurors may be more likely to comply with the request to disregard the evidence ( Steblay et al., 2006 ). Simultaneously, though, admonitions may result in a backfire effect, or emphasis on the information that is supposed to be disregarded ( Leiberman et al., 2009 ). Thus, similar to PTP, the best solution seems to be to prevent jurors from learning the extra-evidentiary information.

Trial Factors

Effects of trial procedure on juror decision-making.

We have explored intersections of trial factors with other factors affecting jurors’ decisions previously in this chapter (e.g., the voir dire procedures in capital cases and effects of jurors’ attitudes and demographics on decision-making). In addition to these intersections, characteristics of the trial itself can also affect the quality and content of the jury’s decision. Research on several of these trial factors was inspired by US Supreme Court decisions ruling on the rules governing the jury processes.

For example, in Williams v. Florida , 3 the Court ruled that criminal juries could contain six jurors instead of twelve jurors, opining that juries of six and twelve members were functionally equivalent. Subsequently, psychologists investigated this assumption of functional equivalence. Combining these studies in a meta-analysis showed that smaller juries (vs. larger juries) had shorter, less thorough deliberations and were less accurate in evidence recall. However, juries rendered similar verdicts regardless of size, with the exception that larger juries were more likely to hang or not reach a decision than smaller juries ( Saks & Marti, 1997 ).

Effects of Jury Reforms on Decision-Making

Other trial factors intended to improve jury decision-making include improving jury instructions and allowing juror note taking or question asking. In some studies, note taking improved jurors’ memories for complex evidence (e.g., Forsterlee et al., 2005 ), and in others, note taking had no effect (Heuer & Penrod, 1988 , 1994 ). Similarly, revising jury instructions can improve verdict outcomes in reducing racial discrimination and increasing appropriate use of evidence, although the results here are also mixed and may depend other factors ( Bornstein & Greene, 2017 ). Last, juror question appears to help jurors feel satisfied with the examination of witnesses (Heuer & Penrod, 1988 , 1994 ). Thus, it appears that many of the reforms proposed to help jurors make better decisions have fewer or smaller effects on decision-making than anticipated by those championing them, but the effects also do not harm the decision-making process and may improve the jurors’ subjective experiences ( Kovera & Levett, 2015 ).

Are Judges a Better Alternative?

Given the shortcomings of the jury in decision-making, one must consider what viable alternative we have to the layperson as a legal decision maker. That is, one must consider the competence of the jury in the context of an alternative decision maker ( Robbennolt & Eisenberg, 2017 ). In the United States, the most relevant comparison group is the judge. Most studies examining whether judges and juries agree on final verdict show high levels of agreement. In their seminal study, Kalven and Zeisel (1966) showed judges and juries agreed 78 percent of the time, with jurors tending to be more lenient compared to judges in cases of disagreement ( Kalven & Zeisel, 1966 ), although other studies have not found evidence of jury leniency ( Clermont & Eisenberg, 1992 ).

In considering evidence, judges and juries seem to have similar difficulty considering nuances of evidence in at least some areas. For example, in several studies judges and juries were similarly insensitive to variations in scientific evidence (e.g., Chorn & Kovera, 2019 ; Kovera & McAuliff, 2000 ). Also similar to jurors, judges also seem vulnerable to the effects of inadmissible evidence ( Landsman & Rakos, 1994 ). Given the high levels of agreement on verdict and similar shortcomings in the evaluation of evidence, there is no strong evidence to believe that judges would be more competent decision makers than jurors.

Implications, Next Steps, and Future Directions for Research

To judge whether the jury is competent, the best question to ask is not whether the jury made the “right” or the “best possible” decision ( Bornstein & Greene, 2017 ). Instead, one should consider whether the decision the jury made was reasonable in the context of the evidence provided ( Bornstein & Greene, 2011 ). According to this metric, the jury is a generally competent decision-making body, albeit an imperfect one ( Bornstein & Greene, 2017 ). Certainly, it is possible to improve the jury’s decision, and doing so would increase just outcomes through reducing wrongful conviction and unjust civil judgments. However, to argue that the jury is incompetent is an overreach, especially when considered in context of the rate of judge–jury agreement and the strongest predictor of verdict (strength of evidence).

Given the limitations of the jury, it is important to continue the work to understand the theoretical mechanisms and factors that explain the jury’s decision and to develop science-based mechanisms for improving the jury’s decision. Given these goals, researchers integrate more of what we know about factors that affect jurors’ decisions with the theoretical models for how jurors and juries make decisions. Further, knowing that the effects of trial participant characteristics and evidentiary and extra-evidentiary factors are often dependent on one another and/or the context in which the trial occurs, paying special attention to these interactions and the limitations of effects based on context is particularly important. In addition, much of the research in jury reform has been spurred by changes in procedure initiated by policymakers or the court (Kovera & Levett, 2014). Future research could attempt to reverse the process. That is, psychologists could work to identify the psychological mechanisms that could improve jurors’ decisions, and then create the procedural reform based on the psychological mechanism, rather than responding to intuitive attempts at reform initiated by legal actors.

Methodologically, the area of jury decision-making presents some particularly difficult hurdles for researchers. The best designed study would likely include a large community member sample (preferably folks who reported for jury duty) viewing a live or videotaped trial and deliberating in groups. However, it is impossible for all jury studies to meet these criteria—especially when considering the number of juries and jurors required to obtain sufficient power to test the effects of manipulations on the jury’s verdicts (see Giner-Sorolla et al., 2020 , for a discussion of power and planning sample size). Instead, it will behoove us as jury researchers to carefully consider our research questions and how the results of those studies will be affected by our methodological choices. Then, we need to carefully justify our methodological choices and explain our limitations in light of those considerations. And above all, we need to replicate our work, using the same stimuli and then different stimuli to ensure generalizability.

As stated in the introduction, jury trials exist in a paradox in our modern society ( Bornstein & Greene, 2017 ). They are simultaneously symbolic of the ideals of democracy and simultaneously flawed and imperfect. As researchers, we can work to improve the jury’s decision by understanding the nuances of how juries decide and then working to create procedures and policies that will lead to a greater proportion of just outcomes.

Acknowledgments

This research was supported by grants from the National Science Foundation (NSF) to the author under Grant Number SBE -1123758. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. The author has no known conflicts of interest to report.

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Ground-breaking research to ensure juries are fair and effective

The UCL Jury Project’s ground-breaking research on the jury system has directly influenced government and judicial policies and practices, as well as public debate, both nationally and internationally.

The UCL Jury Project, led by Professor Cheryl Thomas QC (UCL Laws), has pioneered the study of the jury system. 

Due to their highly confidential nature, Cheryl is the only academic in the country who conducts research with real juries. She has been conducting research on judges and juries for nearly 20 years.  This includes the first study in the UK to examine the impact of diversity on the judicial appointments process and the first survey of judges on their working lives.   The UCL Jury Project conducts research with real juries in Crown Courts across England and Wales and in Northern Ireland. It has tackled some highly sensitive and controversial issues including; racial discrimination, representation on juries, juror internet and social media use, government reporting of conviction rates, whether juries believe rape myths and the emotional impact of serving on a jury.    In 2017 research carried out by Cheryl and her team influenced some of the 35 recommendations made in the Lammy Review on the treatment of BAME individuals in the Criminal Justice System. 

In 2013, Cheryl carried out research to determine jurors’ understanding of the rules on internet and social media use during trials. She found that 23% of serving jurors said they were unclear about what was permitted. This lack of understanding could result in jurors committing a criminal offence, being prosecuted and sent to prison.  

To address this problem and better protect members of the public who serve on juries, Cheryl designed a Juror Notice in Easy Read style that is now used in all jury trials in England and Wales. The Juror Notice has resulted in almost 100% understanding amongst serving jurors about the restrictions they are under in using social media, researching people involved in their case, and discussing the case with family and friends during the trial.

The impact of the Jury Project is far reaching, influencing many areas of the judicial system. From law reform proposals on contempt, improper juror conduct and the insanity defence to improving the quality of debate about trial by jury.  It has been widely covered in the media and Cheryl is a much sought after guest on radio and podcasts on matters involving the judiciary.

The UCL Jury Project has been funded by the Ministry of Justice, Economic and Social Research Council and the Nuffield Foundation.

• The UCL Jury Project
• Are juries fair? The research report submitted to the Ministry of Justice
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Jury Trials Research Paper

View sample criminal justice research paper on jury trials. Browse other research paper examples for more inspiration. If you need a thorough research paper written according to all the academic standards, you can always turn to our experienced writers for help. This is how your paper can get an A! Feel free to contact our writing service for professional assistance. We offer high-quality assignments for reasonable rates.

Public praise and criticism for the jury have a long history, and high profile jury trials are a staple of modern press coverage. However, it is only in the past forty years that researchers have published systematic empirical studies of jury behavior. Study of the jury is a particularly thorny project because the jury speaks publicly only through its verdict. At the end of the trial the jury retires to deliberate in the privacy of the jury room. It emerges occasionally to ask a question, but more commonly, only to report its verdict.

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The jury in the United States gives no explanation for its verdict and the jurors can return to their pretrial lives without revealing any information about how they arrived at their decisions. Research on the jury, as a result, has relied on a variety of indirect methods, each with strengths and limitations: (1) archival studies of jury case characteristics and verdict patterns (records provide information on large samples of cases, but courts record a limited number of variables); (2) post-trial interviews with jurors (the jurors are reporting on the actual process of reaching a verdict, but what they report is limited to what jurors noticed, accurately recorded, remember, and are willing and able to report); (3) surveys of other trial participants, such as judges and attorneys (these respondents are informed court observers, but they have only indirect information on jury behavior and their reports may be influenced by the verdict); (4) field experiments (these can offer strong evidence on the impact of a legal reform like juror note-taking, but they provide little information on process and are hard to implement successfully); and the most common approach; (5) simulation experiments (simulations are strong on process information and provide unambiguous causal inference, but generalizability of findings depends on correspondence with dynamics of real jury behavior). By combining these various approaches, researchers have compiled a nuanced, although incomplete, picture of jury behavior.

The Role of The Jury in The Criminal Justice System

Most criminal cases, even in the United States, end in dismissals or guilty pleas. In addition, if the case does go to trial and the defendant does not exercise the right to a jury trial, it will be decided by a judge. An estimated 150,000 jury trials occur in state courts and an additional 10,000 (half of them criminal trials) in federal courts. Yet the influence of the jury extends far beyond the trials it actually decides. The terms of a plea agreement and the decision to let a judge decide the case are based on what attorneys and defendants anticipate would happen if the case were decided by a jury.

The jury also plays a political role in the criminal justice system. In addition to deciding cases, the jury is a potential source of legitimacy for the legal system. To the extent that the jury is viewed as representing a fair cross-section of the community, its verdict is likely to be seen as the product of fair consideration and can carry a legitimacy that the decision of the judge, as an employee of the state, may lack. Even when the jury’s verdict is unpopular, and even if observers believe that the jury does not fairly represent the community, the jury acts as a lightning rod, insulating the judge and other parts of the state legal system from criticism.

The jury also can act as a conduit for community standards. For example, in evaluating a claim of self-defense, the jury must determine what a reasonable person would be expected to believe, as well as what the particular defendant did believe. Although the jury is charged with applying the law it receives from the judge to the facts, this example illustrates the fuzziness of the division between law and facts. The jury must often inject its understanding of appropriate standards into its fact-finding even while scrupulously following the instructions that the judge provides.

A final political role for the jury is its educative function, identified by Alexis de Toqueville as the jury’s great strength. Surveys suggest that more than one-half of American adults have had some personal involvement with the courts; of this sub-group, half have served on a jury. Citizens also receive information and misinformation on the courts from other sources, including the media. The extent to which jury service provides additional or corrective information is unclear, but jury experience tends to make jurors feel more positive about the jury system.

Judge Versus Jury

One way to evaluate jury behavior is to compare the decisions reached by juries with those reached by judges. Studies of judge-jury agreement reveal substantial, but not uniform agreement. In Kalven and Zeisel’s classic study of jury trials, judges reported the jury verdicts for each of the jury trials over which they presided. They also indicated how they would have decided the cases if they had been bench trials. In 78 percent of the cases, the judge and jury agreed on the verdict. In disagreement cases, the judge would have convicted when the jury acquitted in 19 percent of the cases and the jury convicted when the judge would have acquitted in 3 percent of the cases, a net leniency of 16 percent.

When disagreement arose, it was not attributable to case complexity. Cases that the judge rated as high in complexity were no more likely to stimulate disagreement between the judge and jury than were cases that were low in complexity. The disagreements emerged most often (in 45 percent of the disagreement cases) from the combination of a difference in interpretation of the evidence (the jury’s traditional fact-finding role) and an issue of values (e.g., the jury’s preference for an expanded version of the law of selfdefense). Different conclusions about the facts alone accounted for 34 percent of the disagreements, and values alone accounted for only 21 percent of the disagreements.

Kalven and Zeisel collected their data in the late 1950s, but despite many changes in the makeup of the jury pool and the bench, a very similar pattern was found more recently by Heuer and Penrod. In a sample of criminal trials, they obtained a rate of 74 percent agreement, with the judge convicting when the jury would have acquitted in 23 percent of the cases and the jury convicting when the judge would have acquitted in 3 percent of the cases, a net leniency of 20 percent.

A few researchers have examined the impact extra-legal factors, such as inadmissible evidence, or judicial decisions. The results suggest that judges as well as jurors are susceptible to cognitive biases that can influence their verdicts.

How Jurors Evaluate Evidence

The traditional legal model of the jury trial portrays jurors as passive recipients of the evidence and legal instructions. However, empirical studies of jury behavior find jurors to be active processors of incoming information. Early models of jury decision-making included (1) ‘‘averaging models,’’ in which jurors assess and weigh each piece of evidence, combining the results to reach a verdict and (2) ‘‘Bayesian models,’’ in which jurors consider and evaluate each new piece of information, revising their position on the appropriate verdict in light of their prior position and the additional evidence. These formal models have enjoyed limited success as descriptions of how jurors actually decide cases.

Explanation-based models of jury decisionmaking, such as Pennington and Hastie’s story model, provide an account of jury behavior that comports better with empirical evidence about jury behavior. Consistent with the story model, jurors do not simply record and store the evidence for later use as they receive it. Rather, they actively select and organize the trial evidence to construct a story about what happened. The story they construct is based on the evidence, but jurors also use it to fill in gaps in the evidence by drawing inferences based on their understandings of how the world works. Jurors arrange evidence in the form of a sequence of motivated human actions that include important events, the circumstances of the case, inferences about character, and the parties’ motivations and states of mind. By influencing jurors’ understanding of what took place, the order in which facts are presented (i.e., in story order rather than witness order) can affect verdicts. No studies have investigated whether the story model provides a reasonable account of decision-making by judges as well as jurors.

Jury Composition

The modern American jury is far more heterogeneous and representative of the citizenry at large than was the early English jury or even the American jury in the early twentieth century. Nonetheless, the jury is not a random sample of citizens. It is the product of a multi-stage selection process that typically begins with a list of potentially eligible jurors drawn from voter registration lists and often supplemented by lists of individuals holding drivers’ licenses in the general geographic area where the court sits. Prospective jurors may be excused from jury service on the basis of hardship, but losses also arise as a result of geographic mobility, a failure to update the lists, and nonresponse by prospective jurors to a court summons. The loss of prospective jurors in the qualification and summons process results in a systematic underrepresentation of minorities, younger individuals, and those at lower income levels.

The final stage in jury selection occurs when prospective jurors are brought into the courtroom and questioned to determine whether they will serve in the particular case. Those who clearly express preconceived notions about what the verdict in the case should be, and those with clear conflicts of interest, are excused by the judge (the challenge for cause). In addition, the parties can excuse a limited number of prospective jurors without giving a reason (the peremptory challenge). The U.S. Supreme Court has ruled— Batson v. Kentucky, 476 U.S. 79 (1986); J.E.B. v. Alabama ex rel. T.B., 511 U.S. 127 (1994)—that peremptory challenges based on race or gender are constitutionally prohibited, but that prohibition fails to eliminate racially and gender motivated challenges because courts generally require the party making the challenge to provide only minimal justification when the opposing party charges that a challenge was improperly motivated. Also, given the small number of jurors challenged in the typical trial, an attorney can generally identify a unique and nondiscriminatory reason for each challenge.

The result of this variety of shaping and sometimes cross-cutting forces is that juries tend to be somewhat more educated, wealthier and older, and less likely to include a representative number of minorities, as compared to the distribution of these groups in the adult population. Although these differences are likely to persist, the American jury today is more representative than ever before, and is more heterogeneous than the juries of other countries with a jury system. Moreover, jury participation is extensive. Surveys indicate that 25 percent of American citizens are likely to serve on a jury trial at some point in their lives.

Individual Differences

Attempts to predict juror verdict preferences based upon juror’s background characteristics have had limited success. For example, demographic characteristics like gender, race, and age generally account for very little of the variation in jurors’ responses. Attitudinal characteristics can be more powerful, albeit also modest, predictors.

Expectations, beliefs, and values affect the way jurors react to evidence. In that respect, jurors are no different from any other decisionmakers, because people ordinarily scrutinize more carefully, and are more likely to reject, information that is inconsistent with their beliefs and expectations. It is generally easier for people to remember theory-consistent information than theory-inconsistent information; moreover, ambiguous information tends to be interpreted as theory-consistent.

Some types of legal cases and issues are more likely than others to implicate strongly held beliefs or values. A primary example concerns the death penalty: even among jurors willing to impose the death penalty in some cases, the strength of their support for the death penalty can strongly influence the likelihood that they will vote for a death sentence.

Pretrial Publicity

The American constitutional right to a free press occasionally provides the public with information or misinformation about the case that a jury will be asked to decide. Under such circumstances, the constitutional rights to a free press and to a fair trial are potentially at odds. This conflict is not faced in countries like Canada and Great Britain where the press is prohibited from writing about impending trials. For example, pretrial publicity about a defendant’s alleged confession can affect the expectations and beliefs of prospective jurors in the United States. Although some limited research indicates that the effects of some types of pretrial publicity are generally small, it also suggests that jury selection and the passage of time may not eliminate them. In some high-profile cases, the legal system faces not only the cost of moving a trial, but also the increasing difficulty of identifying a location that has not been saturated with pretrial media coverage.

The Jury’s Response to Experts

Trials increasingly involve the testimony of experts who present technical and scientific evidence. The addition of DNA evidence to the usual range of forensic testimony is a prime example. Surveys of jurors indicate that they find expert testimony to be useful, but they are wary of experts and their potential biases, a factor that can affect an expert’s persuasiveness. Jurors typically work hard at trying to understand the content of expert testimony. Motivation, however, is not enough to ensure success and jurors often express concern about their ability to handle complex evidence.

Jurors are instructed to base their verdicts on the evidence presented at trial and legal instructions. However, their ability to fully process the evidence may be reduced if the expert fails to teach as well as attempt to persuade. When faced with technical testimony, jurors look for cues about the trustworthiness of the source, sometimes using the language itself as a cue. When a decision-maker accepts a persuasive message in response merely to cues (e.g., the prestigious credentials or complicated language of the source of the message), and has not processed and evaluated the message itself, the decision-maker is engaging in peripheral (or heuristic) processing. This approach contrasts with the central (or systematic) processing of the expert testimony that occurs if there is a thorough evaluation of the evidence.

There is little evidence to suggest that jurors adopt the position of an expert based solely on peripheral cues. What is more likely to happen is that the juror will reject unintelligible expert testimony. Moreover, unintelligible jargon may lead jurors to give less credence to an expert who displays other evidence of potential bias, such as an unusually high rate of pay.

Jury Size and Decision Rule

Traditional English and American juries consisted of twelve members who were required to reach a unanimous verdict. Some American jurisdictions now permit juries with as few as six members and nonunanimous verdicts of 9–3 or 10–2; England permits a 10–2 verdict if the jury has been unable to reach unanimity within a specified period of time. Reducing jury size increases the likelihood of an aberrant jury verdict. A majority-decision rule tends to reduce the rate of hung juries and to shorten deliberations because jurors in the majority do not need to gain the support of all jury members. It may also result in less thorough deliberations if the deliberators can arrive at a verdict without considering the reasons why there is disagreement among the members of the jury.

Reactions to The Law, Including Nullification

In theory, jurors are expected to apply the law to the facts of the case. However, a verdict rarely reveals whether the jury has applied the judge’s legal instructions, or whether the jury has applied the judge’s instructions accurately. Thus, trial and appellate courts are left to assume that the jury has followed the judge’s instructions when the verdict is consistent with the law under at least one possible interpretation of the facts. Questions about the jury’s use of the legal instructions typically arise at the appellate level only in the context of concerns about whether the trial court has stated the legal standard accurately. If the statement of the law comports with the legal standard, questions are rarely raised regarding whether the judge conveyed the standard clearly enough to be correctly applied.

Jurors might fail to follow the judge’s instructions on the law if they were either unmotivated or unable to apply the instructions. Empirical studies of the jury show that jurors see themselves as obligated to apply the law, and that they spend a significant portion of their time during deliberations discussing the law. Yet, there is also evidence that legal instructions as they are typically given often fail to provide jurors with helpful legal guidance. Nearly twenty years ago, Elwork, Sales, and Alfini examined juror comprehension of several frequently used jury instructions. They showed not only that comprehension was low, but also that it could be significantly improved if the instructions were rewritten using a combination of psycholinguistic tools and common sense.

More recent work has demonstrated additional ways to facilitate comprehension. The traditional approach to jury instructions is to tell the jury only what it is supposed to do, and to avoid directing attention to any matter that the jury should ignore. But failing to address the erroneous beliefs that jurors do have does not make those beliefs go away, and it does not neutralize them. For example, if jurors are worried about whether a defendant not sentenced to death will be eligible for parole, avoiding any mention of the parole issue during jury instructions can leave jurors believing that a swift release is likely. Jurors come to court with expectations, beliefs, and schemas that can powerfully affect perceptions, attention, and recall. When instructions fail to correct inaccurate legal impressions, they miss the opportunity to provide jurors with a meaningful legal framework.

Although the most common source of deviations from legal standards is a failure of the legal instructions to convey clearly what the appropriate legal standard is, jurors also may deviate from the path outlined in the instructions due to cognitive biases or motivational obstacles. Jurors admonished to disregard particular information may find it difficult to do so. Other legal instructions may ask the jurors to engage in mental gymnastics that are not easy to perform, for example, to use a defendant’s criminal record only to assist in evaluating his credibility, but not as evidence of bad character; to forget that they learned about damaging evidence that the judge ruled inadmissible. Yet, jurors may be unwilling or unable to perform the required cognitive adjustments. A series of simulation experiments have illustrated that such inadmissible evidence can affect juror decisions. The remaining question is whether these failures are significantly less likely when the trier of fact is a judge, or whether they represent heuristic patterns of using information that neither a judge nor jury can overcome.

Finally, jurors may depart from the judge’s legal instructions when the application of the legal standard to the particular case so substantially violates the jurors’ sense of justice that they are persuaded to temper the letter of the law. This conduct has come to be known as ‘‘jury nullification.’’ Kalven and Zeisel attributed most of the disagreements they found between judge and jury to evidentiary disputes, reporting that the jury is engaged in only a modest rewriting of the law in cases that are close on the evidence. Yet, even if it is rare, explicit jury nullification of the law plays a central role in conceptions of the jury and has been a source of extensive debate. Although courts have long recognized the power (as opposed to the right) of the jury to nullify, courts and commentators have disagreed about whether juries should be told about that power ( United States v. Dougherty, 472 F.2d (D.C. Cir. 1972); United States v. Thomas, 116 F.3d 606 (2d Cir. 1997)). Empirical research indicates that the distinction between the power and the right matters: when jurors are explicitly instructed that they have the right not to apply the law as the judge describes it, they are more willing to reach verdicts that temper the literal application of the law.

Deliberations

Deliberations resulting in a group verdict distinguish the jury from its chief alternative, the trial court judge, in two ways. First, the jury verdict in principle reduces the likelihood that the decision will represent an idiosyncratic view of a single deviant decision-maker. Second, in theory, deliberations give the jury an opportunity to profit from the resources of its multiple members and to pool its knowledge and sensibilities to resolve differences. Presumably, a jury verdict reflects more than what could be achieved either by a single decision-maker or by mechanically combining or averaging the preferences of the individual members.

The extent to which deliberations actually do affect jury verdicts in criminal cases is in dispute. Some scholars have suggested that jury verdicts simply reflect the position of the majority before deliberations begin. This suggestion is consistent with the verdict-driven jury that takes an immediate vote to see where each juror stands and then focuses its attention on persuading the minority to join the position initially held by a majority of the jurors. When a vote is immediate, it is likely to reflect predeliberation preferences. When a discussion of the evidence precedes a vote (the so-called evidence-driven jury), that vote will be affected by any changes that have occurred as a result of the discussion. Although jurors often call for an immediate vote, discussions can interrupt before a vote is completed, so that first votes often are not immediate and they imperfectly reflect the individual predeliberation preferences of the jurors. Nonetheless, most juries probably do end up reaching a verdict that reflects the majority position that was apparent at the time most of the jurors expressed a verdict preference in deliberations. The majority, using both normative and informational pressure, persuades the minority to accept its position. When the jury in a criminal case is evenly divided on its first vote, some evidence suggests that the ‘‘beyond a reasonable doubt’’ standard will make a not guilty verdict more likely than a guilty verdict.

Reforming Jury Trials

The jury is regularly the subject of calls for reform. Some proposed reforms, such as those advocating that jurors be permitted to take notes and to submit questions for witnesses during the trial, are modest designed changes to assist jurors in reaching well-considered judgments, to improve the comfort of the conscripted citizens who serve as jurors, and generally to optimize jury performance and juror satisfaction. Other proposed reforms, such as the reduction or elimination of peremptory challenges and the call for greater use of nonunanimous verdicts, have serious potential costs. The remaining question is whether the increasing scholarly literature on jury behavior will inform popular and political discussion.

Bibliography:

• ABRAMSON, JEFFREY. We, The Jury: The Jury System and the Ideal of Democracy. New York: Harper Collins, 1994.
• DIAMOND, SHARI, and LEVI, JUDITH. ‘‘Improving Decisions on Death by Revising and Testing Jury Instructions.’’ Judicature 79, no. 5 (1996): 224–232.
• DIAMOND, SHARI; CASPER, JONATHAN D.; HEIERT, CAM; and MARSHALL, ANNA-MARIA. ‘‘Juror Reactions to Attorneys at Trial.’’ Journal of Criminal Law and Criminology 87 (1996): 17–47.
• ELWORK, AMIRAM; SALES, BRUCE; and ALFINI, JAMES J. Making Jury Instructions Understandable. Charlottesville, Va.: Michie, 1982.
• ELLSWORTH, PHOEBE ‘‘Are Twelve Heads Better than One?’’ Law and Contemporary Problems 52 (1989): 205–224.
• FUKURAI, HIROSHI; BUTLER, EDGAR; and KROOTH, RICHARD. Race and the Jury: Racial Disenfranchisement and the Search for Justice. New York: Plenum, 1993.
• HASTIE, REID; PENROD, STEVEN; and PENNINGTON, NANCY. Inside the Jury. Cambridge, Mass.: Harvard University Press, 1983.
• HEUER, LARRY, and PENROD, STEVEN ‘‘Trial Complexity: A Field Investigation of Its Meaning and Effects.’’ Law and Human Behavior 18 (1994): 29–51.
• HOROWITZ, IRWIN. ‘‘The Effect of Jury Nullification on Verdicts and Jury Functioning in Criminal Trials.’’ Law and Human Behavior 9, no. 1 (1985): 25–36.
• KALVEN, HARRY, JR., and ZEISEL, HANS. The American Jury. Chicago, Ill: University of Chicago Press, 1966.
• LIEBERMAN, JOE, and SALES, BRUCE ‘‘What Social Science Teaches Us about the Jury Instruction Process.’’ Psychology, Public Policy, and Law 3 (1997): 589–644.
• MACCOUN, ROB ‘‘Experimental Research on Jury Decision Making.’’ Science 244, no. 4908 (1989): 1046–1450.
• MUNSTERMAN, G. THOMAS, and MUNSTERMAN, JANICE ‘‘The Search for Jury Representativeness.’’ Justice System Journal 11, no. 1 (1986): 59–78.
• PENNINGTON, NANCY; and HASTIE, REID. ‘‘Evidence Evaluation in Complex Decision Making.’’ Journal of Personality & Social Psychology 51, no. 2 (1986): 242–258.
• SAKS, MICHAEL, and MARTI, MOLLIE W. ‘‘A Meta-Analysis of the Effect of Jury Size.’’ Law and Human Behavior 21, no. 5 (1997): 451–467.
• SANDYS, MARLA, and DILLEHAY, RONALD ‘‘Firstballot Votes, Predeliberation Dispositions, and Final Verdicts in Jury Trials.’’ Law and Human Behavior 19, no. 2 (1995): 175–195.
• SMITH, VICKI, and STUDEBAKER, CHRISTINA A. ‘‘What Do You Expect?: The Influence of People’s Prior Knowledge on Crime Categories on Fact-finding.’’ Law and Human Behavior 20, no. 5 (1996): 517–532.
• THAMAN, STEPHEN. ‘‘Europe’s New Jury Systems: The Cases of Spain and Russia.’’ Law and Contemporary Problems 62 (1999): 233–259.

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• Analysis & Opinion

Can We Trust the Jury in Trump's Manhattan Trial?

Can We Trust the Jury in Trump’s Manhattan Trial?

Experience shows that juries take seriously their duty to set aside their biases and decide where the truth lies.

This piece with originally  published  on  cafe.com  and is reprinted with their kind permission.

How best to decide who is guilty of committing a crime? Until 1641, when it was abolished, the Star Chamber, a group consisting of members of the King’s Council, made those decisions in England when people who were considered too powerful for ordinary courts were under suspicion. You can guess how that ended — in corruption. King Charles I used the Star Chamber to crush opposition to his policies. That’s the likely outcome when the criminal justice system is controlled by the head of state. 

Our Founding Fathers, eager to leave behind all the trappings of a system where kings were above the law, established a jury system for both civil and criminal trials, importantly, leaving decisions about who is guilty and of what to a jury of a defendant’s peers. In  Federalist Papers  No. 83, Alexander Hamilton wrote, “The friends and adversaries of the plan of the convention, if they agree in nothing else, concur at least in the value they set upon the trial by jury; or if there is any difference between them it consists in this: the former regard it as a valuable safeguard to liberty; the latter represent it as the very palladium of free government.”

In practice, there are sometimes questions about juries’ verdicts; the O.J. Simpson and Kyle Rittenhouse acquittals, the convictions of the Central Park Five for a rape they were proven innocent of, but only years later. These cases present important issues, but they are also outliers. Tens of thousands of criminal cases go to trial across the country every year, and juries handle them successfully. It is not a perfect system, but no one has come up with a better one. And the jury system fulfills the important purpose of providing citizens with a check on the enormous power invested in prosecutors. Donald Trump demonstrates that principle, with his  recent boast  that he intends to use the criminal justice system to prosecute people he considers his enemies if he’s reelected. A jury is one of the primary lines of defense against that sort of corruption of the system.

But how does it work when the man who has acknowledged he wants to corrupt the system is the one who’s on trial? That’s what we’re watching play out in a Manhattan courtroom. For too many people, their view about whether the jury system “works” may come down to the verdict — if it aligns with their view of the case, then they’ll think the jury got it right.

That’s one of the results of living in an era where public trust in essential democratic institutions has been sharply eroded. Much of the damage has been done by politically motivated people who see advantage for themselves where the foundations of our system of laws and government are no longer credible, as with Trump’s attacks on law enforcement and the intelligence community. Institutions of long-standing integrity are vulnerable to attacks, like the ones on public health that undercut our safety during a pandemic or Trump’s more personally motivated attack on the National Archives, a custodian for our nation’s history. As we’ve learned, over time, if you undercut public confidence in the institutions, it becomes more difficult for them to work effectively and our way of life is disrupted in ways big and small.

It’s easy to form an impression about a case from what you see on television or read in the press. But juries have an entirely different level of exposure to the evidence in a case. They are instructed in the law by the judge, they hear all of the evidence from start to finish, and they can observe the demeanor of the witnesses firsthand. They are charged with paying close attention from their front row seats and at the end of trial, can listen to the lawyers’ assessment of the case and how the evidence fits together. And then, they deliberate. 

Jurors undoubtedly bring their own prejudices and biases to the courtroom. However, experience shows they take the judge’s instructions to set them aside seriously. After the trial of Paul Manafort, a juror who identified herself as a Trump supporter was interviewed and  said , “I did not want Paul Manafort to be guilty, but he was, and no one’s above the law.” When twelve Americans with different views and backgrounds come together in the jury room, their interaction leads them to set aside preconceived notions and deliberate seriously in most cases. 

Will that happen when Trump’s jury deliberates? Can we have confidence in their verdict? Trump is already suggesting that we can’t if he’s convicted, in a move that’s reminiscent of the way he operated for months in advance of both the 2016 and 2020 elections to suggest that if he lost, the outcome was rigged. As jury selection got underway, he  posted  on Truth Social that Fox Host Jesse Watters said, “They are catching undercover Liberal Activists lying to the Judge in order to get on the Trump Jury.” (Watters, in fact, said the first part, but Trump added on the bit about doing it to get on his jury.) His post earned him another finding of contempt from the judge in the case. 

After 25 years of service as a federal prosecutor, I continue to have confidence in the jury system. The Manhattan DA’s case against Trump is a complicated one, based in some important regards on circumstantial evidence. The jury will have to decide whether to believe it. They will also have to decide which witnesses they believe, and, in order to convict on felony charges, they will have to agree that the prosecution has established that the false business records were created to conceal or assist in the commission of another crime. This is why we have a jury system — when cases are obvious or easy, they typically resolve with a plea agreement. When there is a dispute over the facts, someone has to decide where the truth lies and whether a guilty verdict is warranted. We could leave questions of guilt in the hands of a judge, or a king, or his star chamber. We do not. We entrust the lives and liberties of people who are accused of crimes in this country to the collective wisdom of juries. 

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'Chicken scratch' notes, Trump's book, and a 2006 picture: See evidence in hush money trial

By time Donald Trump 's hush money trial concluded its fourth week, witness testimony swung drastically from accounting processes to Stormy Daniels ' blockbuster story about sex with Trump.

Trump has been indicted on 34 counts of falsifying business records. Prosecutors say he covered up reimbursements to Cohen, who paid Daniels $130,000 to keep her story under wraps ahead of the 2016 election. More than a dozen people have taken the stand, and they all come with tidbits of evidence to explain to the jury.

Prosecutors appear to be using that evidence to show jurors Trump's approach to business and how that led him to signing checks to Cohen himself, while also propping up Daniels' alleged sexual encounter with the former president in 2006. (Trump denies it happened).

Coupled with courtroom sketches , transcripts of the trial and on-the-ground reporting from USA TODAY, the following evidence gives insight into what the jurors are seeing and considering:

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The paper trail: Michael Cohen's checks and 'chicken scratch' numbers

Who introduced the evidence: The prosecution. The checks and accounting documents form a central part of the case as prosecutors try to show Trump was reimbursing Cohen for the $130,000 hush money payment to Daniels and falsifying records to cover it up. The defense has denied the payments were reimbursements.

Associated witness: The paperwork has come into play across a few testimonies, as prosecutors try to show the jury the accounting processes behind Trump's organization approving and issuing checks. The documents above were verified by Jeffrey McConney, the former controller at the Trump Organization and Deborah Tarasoff, an accounts payable supervisor at the Trump Organization.

Testimony: McConney calculated how the $130,000 allegedly netted out to $35,000 monthly payments for Cohen's for a "retainer." The $130,000 paid to Keith M Davidson Associates PLC, plus $50,000 paid for technology services, doubled to pad for taxes, plus a $60,000 bonus, equaled $420,000. At a monthly rate, McConney testified, that came to $35,000. Tarasoff testified the check from Trump's personal account was signed by Trump.

Trump Organization junior bookkeeper Rebecca Manochio and former presidential aide Madeleine Westerhout later testified about how checks were signed in 2017, once Trump was in the White House. They had to send them via FedEx back and forth.

Quote from the transcript: "Allen (Weisselberg) said we had to get some money to Michael, reimburse Michael. He tossed a pad towards me, and I started taking notes on what Allen said," McConney said of his "chicken scratch" notes during a January 2017 meeting.

He also testified the hand writing on the bottom left of the First Republic Bank account statement belonged to Weisselberg, the former Trump organization CFO convicted of tax fraud and falsifying business records.

'I sign all my own checks, so I know where my money's going'

Who introduced the evidence: The prosecution.

Associated witness: Sally Franklin , a senior vice president and executive managing editor in publishing at Penguin Random House.

Testimony: Franklin read loud several portions of Trump's books, in which Trump outlines his approach to business, which includes closely checking invoices and checks. The defense team raised the fact that he used a ghostwriter in cross examination.

Quote from the transcript: "As I said before, I always sign my checks, so I know where my money's going," Trump wrote in his book "Trump: Think Like a Billionaire." "In the same spirit, I also always try to read my bills to make sure I'm not being overcharged"

Photos of Trump and Stormy Daniels at Lake Tahoe golf tournament, 2006

Associated witness: Stormy Daniels, the adult film star who allegedly had sex with Trump in July 2006 at a Lake Tahoe golf tournament.

Testimony: Daniels testified she met Trump while she was working for adult film company Wicked Pictures, a sponsor for the tournament. Trump has denied a sexual encounter between them ever occurred. These photos demonstrated that the two were at least in the same place at the same time.

Transcript excerpt: "So, Wicked sponsors one of the holes on the golf course, which, yes, I know it's very funny. We are an adult film company sponsoring one of the holes," Daniels said on the stand, before describing being introduced to Trump, along with several other golfers. "The owner of the company was like...'this is my contract star and director Stormy Daniels.' And that's when he acted like, oh, you actually direct too? You must be the smart one. And there is a picture and they moved on."

'Oh my god': Stormy Daniels testifies on spanking Trump, his gold tweezers, and silky PJs

Stormy Daniels book and merchandise

Who introduced the evidence: The defense.

Associated witness: Stormy Daniels.

Testimony: Defense lawyer  Susan Necheles pressed Daniels on how she has profited from telling her story. Daniels confirmed a post on social media saying that she made $1 million from her 2018 book "Full Disclosure ," which covered her life story, including the interaction with Trump. Daniels also has other themed merchandise for sale like a candle and a comic book, she confirmed on the stand. Necheles suggested Daniels made up the story of having sex with Trump.

"If that story was untrue, I would have written it to be a lot better," Daniels shot back. "I didn't have to write this one."

Contributing: Aysha Bagchi, Bart Jansen

Trump Trial Turns to Debate Over Jury Instructions After Defense Rests

The jury has been dismissed until closing arguments next Tuesday, but the judge and lawyers from both sides met to hash out how jurors will be instructed before deliberatioms. Donald J. Trump did not take the stand in his own defense.

• Share full article

Jesse McKinley and Kate Christobek

A swift defense and a decision ahead: 5 takeaways.

On Tuesday morning, five weeks after the first jurors were seated for the criminal trial of Donald J. Trump, the defense rested, with closing arguments and then jury deliberations scheduled for after Memorial Day weekend.

And, despite dangling the possibility, Mr. Trump did not testify.

Testimony started April 22 with a tabloid publisher called by the prosecution, David Pecker, and ended with a lawyer called by the defense, Robert Costello. In between were a porn star, Stormy Daniels; Mr. Trump’s former lawyer and fixer, Michael D. Cohen; an erstwhile aide of Mr. Trump, Hope Hicks; and a bevy of lesser-known witnesses, mostly for the prosecution.

The former president is charged with falsifying 34 business records to hide Mr. Cohen’s reimbursement for a $130,000 hush-money payment he made to Ms. Daniels, who says she had sex with Mr. Trump in 2006. Mr. Trump, 77, has denied the charges and the encounter. If convicted, he could face prison or probation.

Here are five takeaways from Mr. Trump’s 20th day on trial.

The defense’s big witness may not have been a great idea.

Mr. Costello, once Mr. Cohen’s informal adviser, continued on the stand on Tuesday, after a reprimand Monday from Justice Juan M. Merchan, who said he had been “contemptuous.”

Mr. Costello had been called by the defense to attack Mr. Cohen’s credibility, but during cross-examination, prosecutors sought to portray him as an agent of Mr. Trump, suggesting he was trying to prevent Mr. Cohen from cooperating with federal investigators. That included reading an email from Mr. Costello saying he was trying to “get Cohen on the right page.”

The defense had hoped to damage Mr. Cohen — a key prosecution witness — beyond repair. Mr. Costello’s choppy performance may be remembered, too.

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Trump talked a lot, just not in court.

Mr. Trump’s vociferousness has never been questioned. During the trial, he regularly spoke outside the courtroom, including Tuesday, when he repeated refrains slamming the trial and complaining about the courtroom temperature.

While he called the trial “election interference,” saying it was impeding his campaign, Mr. Trump did squeeze in rallies on weekends and off-days, as well as some golf .

But after teasing an appearance on the stand, he declined to testify. And after violating a gag order 10 times, he carped carefully, particularly after Justice Merchan threatened jail time.

Trump’s entourage exhibited his pull over his party.

Republican politicians might not normally flock to defend a person enmeshed in a trial prompted by a porn star’s story of extramarital sex. But Mr. Trump has a tight hold on his party, and right-wing luminaries came to support their presumptive presidential nominee.

Throughout the trial, visitors included several potential vice-presidential candidates — including Senator J.D. Vance, an Ohio Republican, and Vivek Ramaswamy, who was once Mr. Trump’s primary opponent — and a brood of Republican lawmakers. Mr. Trump’s son, Donald Jr., also attended Tuesday; another son, Eric, was a regular. There was also a former leader of New York’s Hells Angels chapter.

Many visitors then attacked witnesses, something Mr. Trump could not do because of the gag order.

Perhaps the most notable attendee was Mike Johnson, the speaker of the House, who called the trial “corrupt” and a “sham.” It was a remarkable attack on the legal system by a staunch conservative who is second in line to the presidency — and an indication of Mr. Trump’s sway.

Some key figures were never called to the stand.

Notable as some witnesses were, absences were also interesting. One big name: Karen McDougal, a former Playboy model who says she had an affair with Mr. Trump in 2006 and 2007. Mr. Trump denies this, and she was not called as a witness, though she indicated she was keeping an eye on the case .

Other unseen characters who were frequently mentioned included Keith Schiller, the former president’s bodyguard, and Dylan Howard, a former editor of The National Enquirer, who had a medical condition that prevented him traveling from Australia.

Both might have told interesting tales: Mr. Howard helped buy up and bury unflattering stories about Mr. Trump, including Ms. McDougal’s. He also participated in discussions about Ms. Daniels’s story.

Mr. Schiller was close to Mr. Trump, and fielded a call from Mr. Cohen in which Mr. Cohen says he discussed Ms. Daniels with the former president. But Mr. Schiller was not called by the prosecution or defense.

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It will be at least a week before the jury starts to deliberate.

Jurors will return May 28 for closing arguments, which Justice Merchan predicted would last the entire day. On Tuesday afternoon, lawyers argued over jury instructions, an important part of any trial.

After several hours of debate, with both sides seemingly winning some points, Justice Merchan said he would provide a final version of those instructions on Thursday.

Justice Merchan said he hoped deliberations would begin May 29. And after sitting silently through 22 witnesses over 16 days of testimony, the jurors’ verdict will be unprecedented: the first in an American president’s criminal trial.

Jonah Bromwich

The judge tells the lawyers that he will get them a final version of the jury instructions by the end of the day on Thursday. We won’t know his final rulings until then, but court is adjourned.

Testimony in the case is over. The next time we see the jury will be a week from now, for closing arguments. Thanks for reading.

The week before the trial began, Emil Bove, one of the defense lawyers, worked hard to delay it at an appeals court. He mounted daily arguments that it should be postponed, all of which failed. His work in this conference is similar — he has offered numerous arguments, most of which the judge seems inclined to rule against. Bove is making a valiant effort to affect the jury instructions. But I haven’t heard him make many gains as this crawls to a close.

Justice Merchan finally expressed impatience as Bove continued to argue. But Bove insisted it was important, and Merchan gave him one more chance to speak. Now, though, the judge is describing his past decisions on the matter at hand: Michael Cohen having been Trump’s lawyer when the charged conduct took place.

“My answer hasn’t changed, and honestly I find it disingenuous for you to make the argument at this point,” Merchan says, instructing Bove not to stand up again. “I let you speak,” he says to the defense lawyer. Now, the judge says, it is his turn to speak.

Bove says that he is not being disingenuous, after clarifying that he is making his argument for the record — meaning if the defense appeals and other judges evaluate this case, Bove wants them to see this. Merchan tells him again he’s repeating himself. He appears to have lost his patience, as he says that the defense lawyers continue to try to make this argument to the jury, and that they will be barred from doing so.

Justice Juan M. Merchan

Presiding Judge

Susan Hoffinger

Trump Lawyer

Michael Cohen

Former Trump Lawyer and Fixer

Stormy Daniels

Porn Director, Producer and Actress

Robert Costello

Former legal adviser to Michael Cohen

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Maggie Haberman

Trump and the prosecutors are back after the break. The number of reporters in attendance at the courthouse has dropped off precipitously this afternoon.

Nate Schweber

Texas's lieutenant governor was among those who praised Trump outside the courthouse on Tuesday, but there was also an opposing voice from the Lone Star State. Cecy Vazquez Dreher stood in Collect Pond Park across the street with a handwritten sign noting that “Loser Trump” still owed her hometown, El Paso, more than a half million dollars for a 2019 rally.

“The El Paso taxpayers are still waiting for his bill to be paid,” said Vazquez Dreher, 57, a real estate agent. She was in town to see friends she made when she attended the Wharton School of Business, which Trump attended as well. When asked if that is where he learned not to pay bills, Vazquez Dreher said: “I don’t think it was part of the curriculum.”

We're taking a short break. Trump leaves the courtroom, carrying a pile of printouts and what appears to be a copy of The New York Times. His entourage follows.

In order to reach a guilty verdict, the defense wanted to require jurors not only to agree unanimously that Trump had falsified records to conceal a conspiracy to win an election by unlawful means. It also wanted jurors to be unanimous on what those unlawful means were.

The defense’s request would have made reaching a verdict all the more difficult. Trump's lawyers argued that while this sort of unanimity was not required by law, it was within Justice Merchan’s discretion to ask for it, and in effect set this case apart from other cases.

Prosecutors fired back, arguing that Trump should be treated like any other defendant. The unique importance of the case, they argued, was not a reason for “deviating from the law, it’s a reason for applying the law.” Merchan appeared to agree, saying, “There’s no reason to rewrite the law for this case.”

The lawyers are now arguing about whether the evidence at trial supported the idea that Trump entered a conspiracy with David Pecker and Michael Cohen in 2015 to suppress negative stories during his presidential campaign. The defense, echoing an argument it made to jurors, suggests that there was nothing criminal about participating in that meeting, and that meeting with The National Enquirer was simply a standard part of campaigning for president.

But if there’s nothing wrong with Trump having participated in the meeting, Justice Merchan asks, why not suggest to the jury that he did so? He then reserves judgment on the wording addressing Trump’s participation in the conspiracy — it sounded to me as if he were inclined to side with the prosecution on that issue, but we won’t know for some time.

The reporters in the room have bristled at the suggestion that the deal with The National Enquirer, in which the tabloid killed negative stories on Trump’s behalf, was a typical agreement for a publication to strike with a politician.

The defense lawyers just seemed to lose a key argument. They had hoped that jurors would be told that they had to find Trump had some intent to enter the conspiracy prosecutors say involved him, David Pecker, the former publisher of The National Enquirer, and Michael Cohen, his former personal lawyer and fixer.

But Justice Merchan pointed out that the felony falsifying business records charges that Trump faces include an intent to conceal another crime. The law doesn't require prosecutors to show that Trump intended to orchestrate a conspiracy, but rather that by falsifying business records, he intended to hide one.

Merchan says he will leave that instruction as is, in a win for prosecutors. It would have been far harder for them to show that Trump intended to orchestrate a conspiracy.

Kate Christobek

Members of the public in the overflow room who came back this afternoon appear engaged despite the often dense arguments over jury iinstructions. A few of them have been using binoculars to get a closer look at the screen displaying the feed from the courtroom.

Jesse McKinley

One person has a foot kicked up on a small suitcase. Real Friday energy in here, as the jury has gone home until next week.

Trump has been shuffling and reading papers in front of him. Occasionally, he’s been whispering with his lead lawyer, Todd Blanche, seated at the defense table next to him.

After lengthy and complex discussion, Justice Merchan responds to a request by prosecutors — that language be included in the jury instructions suggesting it was “reasonably forseeable” that false records would be created as a result of Trump’s conduct — by saying that he’s inclined not to include it. But he reserves judgment for now.

It seems like, on the knottiest issues, Merchan is holding back from making decisions, giving himself time to study the issues further.

The judge makes a joke. He says that on a new draft of proposed orders, the conversation in the courtroom will start with “the most challenging issue facing all of us” — how to pronounce a word.

The word, which he eventually spelled, was “eleemosynary,” which means having to do with charity. “Why do we even have it?” the judge asked. The lawyers didn’t seem to know, and it was removed from the draft of the instructions.

This may be one of the few times the judge, prosecutors and the defense all found something funny.

Five minutes' worth of argument results in a word being pluralized — we went from “crime” to “crimes.”

Susanne Craig

Trump has been perusing documents that were handed to him by his lawyer Todd Blanche. He is not fully engaged in the proceedings, though, and appears to have nodded off at least once this afternoon — his head slowly dropped before snapping back up.

Emil Bove and Matthew Colangelo are making these arguments for the defense and prosecution respectively.

Michael Gold

In the hallway before court resumed, Trump suggested he was flirting with again violating the gag order that keeps him from commenting on witnesses, jurors and some others associated with the case. “We do want to defend our Constitution,” he told reporters. “So at some point, maybe, I will take the chance.”

Trump has already been fined $10,000 for violating the gag order, and Justice Merchan earlier this month threatened to imprison him if he violated it again. Such threats have recently been central to Trump’s claims on the trail and in fund-raising emails that the trial is biased against him.

Justice Merchan just rejected a request from the defense outright, about specifying that candidates were not limited, in the years leading up to Trump's election — 2015 and 2016 — from contributing funds to their own campaigns. The prosecution called it a misleading request and the judge determined it was unnecessary for him to explain it to the jury.

He has, however, reserved his final decision on the argument over the word “willfully.”

To begin, if you are seeking to follow this conference, you need to know that the 34 falsifying business records charges against Trump are felony charges because prosecutors say he used the false records to try to conceal a second crime.

That second crime, prosecutors have specified in their proposed jury instructions, is a violation of a state election law that forbids a person from seeking election by “unlawful means.”

So, currently, the defense and prosecution are debating what types of unlawful means apply. The defense is asking for additions that would make it clear that only crimes should count, while the prosecution suggests that civil violations should apply, too.

For the first time there are plenty of open seats in the overflow room, where the media and public can watch the court proceedings on jumbo television screens.

Just to give you a sense of how legally wonky this charge conference will be, we start with the judge asking the defense to argue on behalf of one of its requests: to add the word “willfully” in two places to the instructions that will be given to the jury on a federal election law that is not among the charges.

Charge conferences are often complex, but the knotty charges brought against Trump by the Manhattan district attorney’s office mean we're in for a particularly abstruse affair today.

For this reason, we will strive to give our readers high-level updates that we hope will help them understand what both sides want, and where the judge seems to be leaning.

We’re about to begin the afternoon session in the courtroom, where prosecutors and defense lawyers will make arguments about how the judge should instruct the jury regarding the law. He will deliver those jury instructions next week, after closing arguments.

Trump has returned with members of his entourage, including his oldest son, Donald Trump Jr.; Chuck Zito, the former Hells Angel leader and actor; and the actor Joe Piscopo.

William K. Rashbaum and Maggie Haberman

Prosecutors and Trump’s lawyers will jockey for an edge with jurors in a charge conference.

The testimony in the trial of Donald J. Trump has been riveting and salacious, focusing on a tryst with a porn star and a hush-money payment that paved the road to the White House.

On Tuesday afternoon, the trial will take a decidedly less dramatic — but critically important — turn, as prosecutors and the defense dig into the dry legalities that will guide the jurors as they deliberate.

During the charge conference, the two sides are expected to lay out their dueling visions for how the judge should instruct the jury as it prepares to weigh the charges against Mr. Trump — 34 felony counts of falsifying business records.

Jury instructions are typically meant to translate legal treatises into something intelligible to the 12 laypeople who will decide the case. The instructions provide jurors with a road map to help them apply the law to the facts they have gleaned from the witnesses, documents and other evidence that has been presented to them.

The New York Times has obtained early drafts of each side’s proposed jury instructions, which were filed with the court in recent days and will underpin their arguments to the judge, Juan M. Merchan. That conference will take place outside the presence of the jury.

The prosecutors’ proposed instructions, among other things, ask the judge to give the jury what legal experts said was unusual flexibility in determining whether Mr. Trump had a role in the creation of the false records at the center of the charges.

Prosecutors argue that even if Mr. Trump did not create the records himself, the jury can find him responsible if the creation of the false records was “a reasonably foreseeable consequence of his conduct.”

The defense’s request drilled down on a variety of other issues that they already sought to raise at trial.

One such issue is their suggestion that Michael D. Cohen, the prosecution’s star witness, improperly deleted data from his phone. In their request for jury instructions, they asked the judge to tell the jurors that they can infer that anything Mr. Cohen may have deleted would have been unfavorable to him.

The proposed instructions provided by both sides, and their arguments in the conference in court, give the lawyers the opportunity to have some input. But the judge has broad leeway in how he will instruct the jury on the law. The jurors will not actually receive the instructions until next week, after they hear closing arguments and shortly before they begin deliberations.

Jury instructions are always crucial, but they will be even more important in this case, which focuses on the cover-up of a sex scandal, but hinges on complex and untested legal issues. That means the outcome of the case could very well turn on the substance of the instructions jurors receive.

Here’s more about the proposals from each side.

Prosecutors want to offer jurors options to convict Trump

To convict Mr. Trump of the felonies he is charged with, prosecutors must show that he falsified business records in order to commit or conceal another crime. The prosecution’s proposed instructions say that other crime is the violation of an election law statue that makes it illegal to conspire to promote or prevent a candidate’s election by “unlawful means.”

But what are those unlawful means? Prosecutors want the judge to instruct the jurors that they can choose any of three options: a federal election law violation; the falsification of other business records; or a tax crime.

The jurors must unanimously agree that Mr. Trump conspired to promote his own election by unlawful means. But prosecutors are asking the judge to instruct jurors that they do not need to reach a unanimous conclusion about what the unlawful means were.

The defense is taking aim at Cohen’s work for Trump

Mr. Trump’s lawyers appear to be referencing one possible defense that Justice Merchan has already rejected: the idea that Mr. Trump was simply following the legal advice of his one-time lawyer, Mr. Cohen.

In their proposed instructions, Mr. Trump’s lawyers asked the judge to remind jurors that Mr. Cohen had served as a lawyer for Mr. Trump while he worked at the Trump Organization. That could suggest to jurors that the former fixer’s role as Mr. Trump’s lawyer should affect the way they view the case as a whole.

This appears to be something of an end run around Justice Merchan’s earlier decision that Mr. Trump could not pursue a so-called advice-of-counsel defense, which argues that someone is not guilty of a crime because they acted based on a lawyer’s advice.

Ben Protess and Wesley Parnell

Costello’s task was to get Cohen on the ‘right page’ for Trump.

Robert J. Costello was the main witness Donald J. Trump’s lawyers called in his criminal trial, and like Mr. Trump, he has great disdain for the prosecution and its case.

During his brief time on the stand Tuesday, Mr. Costello had tense exchanges with Susan Hoffinger, the prosecutor cross-examining him, as they sparred for a second straight day.

Mr. Costello’s testimony centered on his relationship with the prosecution’s star witness, Michael D. Cohen. Mr. Costello, a prosecutor turned defense lawyer, was an informal adviser to Mr. Cohen, the former president’s onetime fixer. Mr. Cohen had made a $130,000 hush-money payment to a porn star on the eve of the 2016 election to silence her account of a sexual encounter with Mr. Trump.

Mr. Cohen testified that Mr. Trump had ordered him to buy the silence of the woman, Stormy Daniels. And he said that he suspected that Mr. Costello was trying to ensure that he would not cooperate with prosecutors after the hush-money deal came to light in 2018. Mr. Costello, Mr. Cohen noted, was close with Mr. Trump’s lawyer at the time, Rudolph W. Giuliani.

On Tuesday, Ms. Hoffinger echoed that claim, suggesting that Mr. Costello was actually an agent of Mr. Trump working to prevent Mr. Cohen from flipping on the then-president.

She produced a litany of emails underscoring her point, including one in which Mr. Costello wrote to his law partner, saying, “Our issue is to get Cohen on the right page without giving him the appearance that we are following instructions from Giuliani or the president.”

And once Mr. Cohen turned on Mr. Trump, pleading guilty to federal crimes for his role in the hush-money, Ms. Hoffinger noted that “you lost control of Michael Cohen for the president.”

Mr. Costello, defiant, declared: “Absolutely not.”

During her questioning, Ms. Hoffinger aimed at Mr. Costello’s credibility, seeking to turn the tables on the defense, which had called Mr. Costello to do the same to Mr. Cohen.

She began by citing Mr. Costello’s first meeting with Mr. Cohen in April 2018, and asked him to confirm that he played up his connection to Mr. Trump’s then lawyer.

“Not true,” Mr. Costello replied, prompting Ms. Hoffinger to show a pair of emails that appeared to contradict his denial.

“I told you my relationship with Rudy which could be very very useful for you,” Mr. Costello wrote Mr. Cohen two days after their meeting.

She also displayed one that Mr. Costello sent to a law partner, saying that Mr. Cohen had good reason to hire him “because of my connection to Rudy Giuliani, which I mentioned to him in our meeting.”

And when Mr. Costello equivocated about when he offered to serve as a back channel to Mr. Trump’s legal team, Ms. Hoffinger showed him an email he sent to Mr. Cohen using that exact phrase. The email recounted a conversation Mr. Costello said he had with Mr. Giuliani, who was “thrilled and said this could not be a better situation for the President or you.”

Mr. Giuliani, he added, “said thank you for opening this back channel of communication and asked me to keep in touch.”

Mr. Costello’s session on Tuesday was more placid than his combustible performance the day before.

Shortly after Mr. Costello took the stand on Monday, prosecutors objected to a series of questions. When the judge sided with them, Mr. Costello muttered “jeez,” registering his dismay and irking the judge, Juan M. Merchan. Mr. Costello tried to retract his remark, mumbling under his breath that he wanted to “strike” it from the record.

The testimony continued, but after more objections, Justice Merchan again grew frustrated. He dismissed the jury, and excoriated the witness: “If you don’t like my ruling, you don’t say, ‘jeez,’ and you don’t say, ‘strike it,’ because I’m the only one who can strike testimony in court,” he said, adding: “Are you staring me down?”

He then cleared the courtroom, dismissing reporters while allowing a group of Mr. Trump’s supporters to remain.

Then, according to a transcript, the judge told Mr. Costello that his conduct was “contemptuous” and said, “If you try to stare me down one more time I will remove you from the stand,” adding, to the defense lawyers, “I will strike his testimony, do you hear me?”

Mr. Costello asked, “Can I say something, please?” And Justice Merchan replied: “No. No. This is not a conversation.”

While a gag order prevents Trump from commenting on witnesses, his supporters and campaign surrogates have freer rein to comment. Outside the courthouse, his oldest son, Donald Trump Jr., attacked Michael Cohen as a liar. He also criticized Stormy Daniels, the prosecution's other star witness, and essentially said that their involvement in the trial made a mockery of jurisprudence.

Matt Whitaker, a former acting attorney general who was a top Trump campaign surrogate in Iowa, said: “We have witnesses who are liars and stealers.”

While this group of close to a dozen people gives a news conference in the streets outside the courthouse, we have dueling chants in the background. As a few people call out “we love Trump,” one woman shouts over them, “lock him up,” a twist on Trump supporters’ rallying cry in 2016.

A man who happened to be walking by this gaggle shouted at Donald Trump Jr., calling him “phony,” adding an expletive, and saying: “We hate you in New York.”

The collision between the courtroom and the campaign trail has long been evident, but of note today: As the Trump campaign has been courting Hispanic voters, Representative Maria Salazar of Florida — in both English and Spanish — is denouncing the Manhattan case as something akin to what takes place in totalitarian Latin American regimes. Trump will hold a campaign event on Thursday in a heavily Latino area in the South Bronx.

Asked why his dad didn’t testify, Donald Trump Jr. did not directly answer the question but repeated his previous description of the trial as a farce. “How do you justify this insanity?” he said. “Look at the clowns” on the stand.

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• Published: 13 May 2024

Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial

• Donna H. Ryan 1 ,
• Ildiko Lingvay   ORCID: orcid.org/0000-0001-7006-7401 2 ,
• John Deanfield 3 ,
• Steven E. Kahn 4 ,
• Eric Barros   ORCID: orcid.org/0000-0001-6613-4181 5 ,
• Bartolome Burguera 6 ,
• Helen M. Colhoun   ORCID: orcid.org/0000-0002-8345-3288 7 ,
• Cintia Cercato   ORCID: orcid.org/0000-0002-6181-4951 8 ,
• Dror Dicker 9 ,
• Deborah B. Horn 10 ,
• G. Kees Hovingh 5 ,
• Ole Kleist Jeppesen 5 ,
• Alexander Kokkinos 11 ,
• A. Michael Lincoff   ORCID: orcid.org/0000-0001-8175-2121 12 ,
• Sebastian M. Meyhöfer 13 ,
• Tugce Kalayci Oral 5 ,
• Jorge Plutzky   ORCID: orcid.org/0000-0002-7194-9876 14 ,
• André P. van Beek   ORCID: orcid.org/0000-0002-0335-8177 15 ,
• John P. H. Wilding   ORCID: orcid.org/0000-0003-2839-8404 16 &
• Robert F. Kushner 17  

Nature Medicine ( 2024 ) Cite this article

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• Medical research

In the SELECT cardiovascular outcomes trial, semaglutide showed a 20% reduction in major adverse cardiovascular events in 17,604 adults with preexisting cardiovascular disease, overweight or obesity, without diabetes. Here in this prespecified analysis, we examined effects of semaglutide on weight and anthropometric outcomes, safety and tolerability by baseline body mass index (BMI). In patients treated with semaglutide, weight loss continued over 65 weeks and was sustained for up to 4 years. At 208 weeks, semaglutide was associated with mean reduction in weight (−10.2%), waist circumference (−7.7 cm) and waist-to-height ratio (−6.9%) versus placebo (−1.5%, −1.3 cm and −1.0%, respectively; P  < 0.0001 for all comparisons versus placebo). Clinically meaningful weight loss occurred in both sexes and all races, body sizes and regions. Semaglutide was associated with fewer serious adverse events. For each BMI category (<30, 30 to <35, 35 to <40 and ≥40 kg m − 2 ) there were lower rates (events per 100 years of observation) of serious adverse events with semaglutide (43.23, 43.54, 51.07 and 47.06 for semaglutide and 50.48, 49.66, 52.73 and 60.85 for placebo). Semaglutide was associated with increased rates of trial product discontinuation. Discontinuations increased as BMI class decreased. In SELECT, at 208 weeks, semaglutide produced clinically significant weight loss and improvements in anthropometric measurements versus placebo. Weight loss was sustained over 4 years. ClinicalTrials.gov identifier: NCT03574597 .

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Effects of a personalized nutrition program on cardiometabolic health: a randomized controlled trial

Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial

What is the pipeline for future medications for obesity?

The worldwide obesity prevalence, defined by body mass index (BMI) ≥30 kg m − 2 , has nearly tripled since 1975 (ref. 1 ). BMI is a good surveillance measure for population changes over time, given its strong correlation with body fat amount on a population level, but it may not accurately indicate the amount or location of body fat at the individual level 2 . In fact, the World Health Organization defines clinical obesity as ‘abnormal or excessive fat accumulation that may impair health’ 1 . Excess abnormal body fat, especially visceral adiposity and ectopic fat, is a driver of cardiovascular (CV) disease (CVD) 3 , 4 , 5 , and contributes to the global chronic disease burden of diabetes, chronic kidney disease, cancer and other chronic conditions 6 , 7 .

Remediating the adverse health effects of excess abnormal body fat through weight loss is a priority in addressing the global chronic disease burden. Improvements in CV risk factors, glycemia and quality-of-life measures including personal well-being and physical functioning generally begin with modest weight loss of 5%, whereas greater weight loss is associated with more improvement in these measures 8 , 9 , 10 . Producing and sustaining durable and clinically significant weight loss with lifestyle intervention alone has been challenging 11 . However, weight-management medications that modify appetite can make attaining and sustaining clinically meaningful weight loss of ≥10% more likely 12 . Recently, weight-management medications, particularly those comprising glucagon-like peptide-1 receptor agonists, that help people achieve greater and more sustainable weight loss have been developed 13 . Once-weekly subcutaneous semaglutide 2.4 mg, a glucagon-like peptide-1 receptor agonist, is approved for chronic weight management 14 , 15 , 16 and at doses of up to 2.0 mg is approved for type 2 diabetes treatment 17 , 18 , 19 . In patients with type 2 diabetes and high CV risk, semaglutide at doses of 0.5 mg and 1.0 mg has been shown to significantly lower the risk of CV events 20 . The SELECT trial (Semaglutide Effects on Heart Disease and Stroke in Patients with Overweight or Obesity) studied patients with established CVD and overweight or obesity but without diabetes. In SELECT, semaglutide was associated with a 20% reduction in major adverse CV events (hazard ratio 0.80, 95% confidence interval (CI) 0.72 to 0.90; P  < 0.001) 21 . Data derived from the SELECT trial offer the opportunity to evaluate the weight loss efficacy, in a geographically and racially diverse population, of semaglutide compared with placebo over 208 weeks when both are given in addition to standard-of-care recommendations for secondary CVD prevention (but without a focus on targeting weight loss). Furthermore, the data allow examination of changes in anthropometric measures such as BMI, waist circumference (WC) and waist-to-height ratio (WHtR) as surrogates for body fat amount and location 22 , 23 . The diverse population can also be evaluated for changes in sex- and race-specific ‘cutoff points’ for BMI and WC, which have been identified as anthropometric measures that predict cardiometabolic risk 8 , 22 , 23 .

This prespecified analysis of the SELECT trial investigated weight loss and changes in anthropometric indices in patients with established CVD and overweight or obesity without diabetes, who met inclusion and exclusion criteria, within a range of baseline categories for glycemia, renal function and body anthropometric measures.

Study population

The SELECT study enrolled 17,604 patients (72.3% male) from 41 countries between October 2018 and March 2021, with a mean (s.d.) age of 61.6 (8.9) years and BMI of 33.3 (5.0) kg m − 2 (ref. 21 ). The baseline characteristics of the population have been reported 24 . Supplementary Table 1 outlines SELECT patients according to baseline BMI categories. Of note, in the lower BMI categories (<30 kg m − 2 (overweight) and 30 to <35 kg m − 2 (class I obesity)), the proportion of Asian individuals was higher (14.5% and 7.4%, respectively) compared with the proportion of Asian individuals in the higher BMI categories (BMI 35 to <40 kg m − 2 (class II obesity; 3.8%) and ≥40 kg m − 2 (class III obesity; 2.2%), respectively). As the BMI categories increased, the proportion of women was higher: in the class III BMI category, 45.5% were female, compared with 20.8%, 25.7% and 33.0% in the overweight, class I and class II categories, respectively. Lower BMI categories were associated with a higher proportion of patients with normoglycemia and glycated hemoglobin <5.7%. Although the proportions of patients with high cholesterol and history of smoking were similar across BMI categories, the proportion of patients with high-sensitivity C-reactive protein ≥2.0 mg dl −1 increased as the BMI category increased. A high-sensitivity C-reactive protein >2.0 mg dl −1 was present in 36.4% of patients in the overweight BMI category, with a progressive increase to 43.3%, 57.3% and 72.0% for patients in the class I, II and III obesity categories, respectively.

Weight and anthropometric outcomes

Percentage weight loss.

The average percentage weight-loss trajectories with semaglutide and placebo over 4 years of observation are shown in Fig. 1a (ref. 21 ). For those in the semaglutide group, the weight-loss trajectory continued to week 65 and then was sustained for the study period through week 208 (−10.2% for the semaglutide group, −1.5% for the placebo group; treatment difference −8.7%; 95% CI −9.42 to −7.88; P  < 0.0001). To estimate the treatment effect while on medication, we performed a first on-treatment analysis (observation period until the first time being off treatment for >35 days). At week 208, mean weight loss in the semaglutide group analyzed as first on-treatment was −11.7% compared with −1.5% for the placebo group (Fig. 1b ; treatment difference −10.2%; 95% CI −11.0 to −9.42; P  < 0.0001).

a , b , Observed data from the in-trial period ( a ) and first on-treatment ( b ). The symbols are the observed means, and error bars are ±s.e.m. Numbers shown below each panel represent the number of patients contributing to the means. Analysis of covariance with treatment and baseline values was used to estimate the treatment difference. Exact P values are 1.323762 × 10 −94 and 9.80035 × 10 −100 for a and b , respectively. P values are two-sided and are not adjusted for multiplicity. ETD, estimated treatment difference; sema, semaglutide.

Categorical weight loss and individual body weight change

Among in-trial (intention-to-treat principle) patients at week 104, weight loss of ≥5%, ≥10%, ≥15%, ≥20% and ≥25% was achieved by 67.8%, 44.2%, 22.9%, 11.0% and 4.9%, respectively, of those treated with semaglutide compared with 21.3%, 6.9%, 1.7%, 0.6% and 0.1% of those receiving placebo (Fig. 2a ). Individual weight changes at 104 weeks for the in-trial populations for semaglutide and placebo are depicted in Fig. 2b and Fig. 2c , respectively. These waterfall plots show the variation in weight-loss response that occurs with semaglutide and placebo and show that weight loss is more prominent with semaglutide than placebo.

a , Categorical weight loss from baseline at week 104 for semaglutide and placebo. Data from the in-trial period. Bars depict the proportion (%) of patients receiving semaglutide or placebo who achieved ≥5%, ≥10%, ≥15%, ≥20% and ≥25% weight loss. b , c , Percentage change in body weight for individual patients from baseline to week 104 for semaglutide ( b ) and placebo ( c ). Each patient’s percentage change in body weight is plotted as a single bar.

Change in WC

WC change from baseline to 104 weeks has been reported previously in the primary outcome paper 21 . The trajectory of WC change mirrored that of the change in body weight. At week 208, average reduction in WC was −7.7 cm with semaglutide versus −1.3 cm with placebo, with a treatment difference of −6.4 cm (95% CI −7.18 to −5.61; P  < 0.0001) 21 .

WC cutoff points

We analyzed achievement of sex- and race-specific cutoff points for WC by BMI <35 kg m − 2 or ≥35 kg m − 2 , because for BMI >35 kg m − 2 , WC is more difficult technically and, thus, less accurate as a risk predictor 4 , 25 , 26 . Within the SELECT population with BMI <35 kg m − 2 at baseline, 15.0% and 14.3% of the semaglutide and placebo groups, respectively, were below the sex- and race-specific WC cutoff points. At week 104, 41.2% fell below the sex- and race-specific cutoff points for the semaglutide group, compared with only 18.0% for the placebo group (Fig. 3 ).

WC cutoff points; Asian women <80 cm, non-Asian women <88 cm, Asian men <88 cm, non-Asian men <102 cm.

Waist-to-height ratio

At baseline, mean WHtR was 0.66 for the study population. The lowest tertile of the SELECT population at baseline had a mean WHtR <0.62, which is higher than the cutoff point of 0.5 used to indicate increased cardiometabolic risk 27 , suggesting that the trial population had high WCs. At week 208, in the group randomized to semaglutide, there was a relative reduction of 6.9% in WHtR compared with 1.0% in placebo (treatment difference −5.87% points; 95% CI −6.56 to −5.17; P  < 0.0001).

BMI category change

At week 104, 52.4% of patients treated with semaglutide achieved improvement in BMI category compared with 15.7% of those receiving placebo. Proportions of patients in the BMI categories at baseline and week 104 are shown in Fig. 4 , which depicts in-trial patients receiving semaglutide and placebo. The BMI category change reflects the superior weight loss with semaglutide, which resulted in fewer patients being in the higher BMI categories after 104 weeks. In the semaglutide group, 12.0% of patients achieved a BMI <25 kg m − 2 , which is considered the healthy BMI category, compared with 1.2% for placebo; per study inclusion criteria, no patients were in this category at baseline. The proportion of patients with obesity (BMI ≥30 kg m − 2 ) fell from 71.0% to 43.3% in the semaglutide group versus 71.9% to 67.9% in the placebo group.

In the semaglutide group, 12.0% of patients achieved normal weight status at week 104 (from 0% at baseline), compared with 1.2% (from 0% at baseline) for placebo. BMI classes: healthy (BMI <25 kg m − 2 ), overweight (25 to <30 kg m − 2 ), class I obesity (30 to <35 kg m − 2 ), class II obesity (35 to <40 kg m − 2 ) and class III obesity (BMI ≥40 kg m − 2 ).

Weight and anthropometric outcomes by subgroups

The forest plot illustrated in Fig. 5 displays mean body weight percentage change from baseline to week 104 for semaglutide relative to placebo in prespecified subgroups. Similar relationships are depicted for WC changes in prespecified subgroups shown in Extended Data Fig. 1 . The effect of semaglutide (versus placebo) on mean percentage body weight loss as well as reduction in WC was found to be heterogeneous across several population subgroups. Women had a greater difference in mean weight loss with semaglutide versus placebo (−11.1% (95% CI −11.56 to −10.66) versus −7.5% in men (95% CI −7.78 to −7.23); P  < 0.0001). There was a linear relationship between age category and degree of mean weight loss, with younger age being associated with progressively greater mean weight loss, but the actual mean difference by age group is small. Similarly, BMI category had small, although statistically significant, associations. Those with WHtR less than the median experienced slightly lower mean body weight change than those above the median, with estimated treatment differences −8.04% (95% CI −8.37 to −7.70) and −8.99% (95% CI −9.33 to −8.65), respectively ( P  < 0.0001). Patients from Asia and of Asian race experienced slightly lower mean weight loss (estimated treatment difference with semaglutide for Asian race −7.27% (95% CI −8.09 to −6.46; P  = 0.0147) and for Asia −7.30 (95% CI −7.97 to −6.62; P  = 0.0016)). There was no difference in weight loss with semaglutide associated with ethnicity (estimated treatment difference for Hispanic −8.53% (95% CI −9.28 to −7.76) or non-Hispanic −8.52% (95% CI −8.77 to 8.26); P  = 0.9769), glycemic status (estimated treatment difference for prediabetes −8.53% (95% CI −8.83 to −8.24) or normoglycemia −8.48% (95% CI −8.88 to −8.07; P  = 0.8188) or renal function (estimated treatment difference for estimated glomerular filtration rate (eGFR) <60 or ≥60 ml min −1  1.73 m − 2 being −8.50% (95% CI −9.23 to −7.76) and −8.52% (95% CI −8.77 to −8.26), respectively ( P  = 0.9519)).

Data from the in-trial period. N  = 17,604. P values represent test of no interaction effect. P values are two-sided and are not adjusted for multiplicity. The dots show estimated treatment differences, and the error bars show 95% CIs. Details of the statistical models are available in Methods . ETD, estimated treatment difference; HbA1c, glycated hemoglobin; MI, myocardial infarction; PAD, peripheral artery disease; sema, semaglutide.

Safety and tolerability according to baseline BMI category

We reported in the primary outcome of the SELECT trial that adverse events (AEs) leading to permanent discontinuation of the trial product occurred in 1,461 patients (16.6%) in the semaglutide group and 718 patients (8.2%) in the placebo group ( P  < 0.001) 21 . For this analysis, we evaluated the cumulative incidence of AEs leading to trial product discontinuation by treatment assignment and by BMI category (Fig. 6 ). For this analysis, with death modeled as a competing risk, we tracked the proportion of in-trial patients for whom drug was withdrawn or interrupted for the first time (Fig. 6 , left) or cumulative discontinuations (Fig. 6 , right). Both panels of Fig. 6 depict a graded increase in the proportion discontinuing semaglutide, but not placebo. For lower BMI classes, discontinuation rates are higher in the semaglutide group but not the placebo group.

Data are in-trial from the full analysis set. sema, semaglutide.

We reported in the primary SELECT analysis that serious adverse events (SAEs) were reported by 2,941 patients (33.4%) in the semaglutide arm and by 3,204 patients (36.4%) in the placebo arm ( P  < 0.001) 21 . For this study, we analyzed SAE rates by person-years of treatment exposure for BMI classes (<30 kg m − 2 , 30 to <35 kg m − 2 , 35 to <40 kg m − 2 , and ≥40 kg m − 2 ) and provide these data in Supplementary Table 2 . We also provide an analysis of the most common categories of SAEs. Semaglutide was associated with lower SAEs, primarily driven by CV event and infections. Within each obesity class (<30 kg m − 2 , 30 to <35 kg m − 2 , 35 to <40 kg m − 2 , and ≥40 kg m − 2 ), there were fewer SAEs in the group receiving semaglutide compared with placebo. Rates (events per 100 years of observation) of SAEs were 43.23, 43.54, 51.07 and 47.06 for semaglutide and 50.48, 49.66, 52.73 and 60.85 for placebo, with no evidence of heterogeneity. There was no detectable difference in hepatobiliary or gastrointestinal SAEs comparing semaglutide with placebo in any of the four BMI classes we evaluated.

The analyses of weight effects of the SELECT study presented here reveal that patients assigned to once-weekly subcutaneous semaglutide 2.4 mg lost significantly more weight than those receiving placebo. The weight-loss trajectory with semaglutide occurred over 65 weeks and was sustained up to 4 years. Likewise, there were similar improvements in the semaglutide group for anthropometrics (WC and WHtR). The weight loss was associated with a greater proportion of patients receiving semaglutide achieving improvement in BMI category, healthy BMI (<25 kg m − 2 ) and falling below the WC cutoff point above which increased cardiometabolic risk for the sex and race is greater 22 , 23 . Furthermore, both sexes, all races, all body sizes and those from all geographic regions were able to achieve clinically meaningful weight loss. There was no evidence of increased SAEs based on BMI categories, although lower BMI category was associated with increased rates of trial product discontinuation, probably reflecting exposure to a higher level of drug in lower BMI categories. These data, representing the longest clinical trial of the effects of semaglutide versus placebo on weight, establish the safety and durability of semaglutide effects on weight loss and maintenance in a geographically and racially diverse population of adult men and women with overweight and obesity but not diabetes. The implications of weight loss of this degree in such a diverse population suggests that it may be possible to impact the public health burden of the multiple morbidities associated with obesity. Although our trial focused on CV events, many chronic diseases would benefit from effective weight management 28 .

There were variations in the weight-loss response. Individual changes in body weight with semaglutide and placebo were striking; still, 67.8% achieved 5% or more weight loss and 44.2% achieved 10% weight loss with semaglutide at 2 years, compared with 21.3% and 6.9%, respectively, for those receiving placebo. Our first on-treatment analysis demonstrated that those on-drug lost more weight than those in-trial, confirming the effect of drug exposure. With semaglutide, lower BMI was associated with less percentage weight loss, and women lost more weight on average than men (−11.1% versus −7.5% treatment difference from placebo); however, in all cases, clinically meaningful mean weight loss was achieved. Although Asian patients lost less weight on average than patients of other races (−7.3% more than placebo), Asian patients were more likely to be in the lowest BMI category (<30 kg m − 2 ), which is known to be associated with less weight loss, as discussed below. Clinically meaningful weight loss was evident in the semaglutide group within a broad range of baseline categories for glycemia and body anthropometrics. Interestingly, at 2 years, a significant proportion of the semaglutide-treated group fell below the sex- and race-specific WC cutoff points, especially in those with BMI <35 kg m − 2 , and a notable proportion (12.0%) fell below the BMI cutoff point of 25 kg m − 2 , which is deemed a healthy BMI in those without unintentional weight loss. As more robust weight loss is possible with newer medications, achieving and maintaining these cutoff point targets may become important benchmarks for tracking responses.

The overall safety profile did not reveal any new signals from prior studies, and there were no BMI category-related associations with AE reporting. The analysis did reveal that tolerability may differ among specific BMI classes, since more discontinuations occurred with semaglutide among lower BMI classes. Potential contributors may include a possibility of higher drug exposure in lower BMI classes, although other explanations, including differences in motivation and cultural mores regarding body size, cannot be excluded.

Is the weight loss in SELECT less than expected based on prior studies with the drug? In STEP 1, a large phase 3 study of once-weekly subcutaneous semaglutide 2.4 mg in individuals without diabetes but with BMI >30 kg m − 2 or 27 kg m − 2 with at least one obesity-related comorbidity, the mean weight loss was −14.9% at week 68, compared with −2.4% with placebo 14 . Several reasons may explain the observation that the mean treatment difference was −12.5% in STEP 1 and −8.7% in SELECT. First, SELECT was designed as a CV outcomes trial and not a weight-loss trial, and weight loss was only a supportive secondary endpoint in the trial design. Patients in STEP 1 were desirous of weight loss as a reason for study participation and received structured lifestyle intervention (which included a −500 kcal per day diet with 150 min per week of physical activity). In the SELECT trial, patients did not enroll for the specific purpose of weight loss and received standard of care covering management of CV risk factors, including medical treatment and healthy lifestyle counseling, but without a specific focus on weight loss. Second, the respective study populations were quite different, with STEP 1 including a younger, healthier population with more women (73.1% of the semaglutide arm in STEP 1 versus 27.7% in SELECT) and higher mean BMI (37.8 kg m − 2 versus 33.3 kg m − 2 , respectively) 14 , 21 . Third, major differences existed between the respective trial protocols. Patients in the semaglutide treatment arm of STEP 1 were more likely to be exposed to the medication at the full dose of 2.4 mg than those in SELECT. In SELECT, investigators were allowed to slow, decrease or pause treatment. By 104 weeks, approximately 77% of SELECT patients on dose were receiving the target semaglutide 2.4 mg weekly dose, which is lower than the corresponding proportion of patients in STEP 1 (89.6% were receiving the target dose at week 68) 14 , 21 . Indeed, in our first on-treatment analysis at week 208, weight loss was greater (−11.7% for semaglutide) compared with the in-trial analysis (−10.2% for semaglutide). Taken together, all these issues make less weight loss an expected finding in SELECT, compared with STEP 1.

The SELECT study has some limitations. First, SELECT was not a primary prevention trial, and the data should not be extrapolated to all individuals with overweight and obesity to prevent major adverse CV events. Although the data set is rich in numbers and diversity, it does not have the numbers of individuals in racial subgroups that may have revealed potential differential effects. SELECT also did not include individuals who have excess abnormal body fat but a BMI <27 kg m − 2 . Not all individuals with increased CV risk have BMI ≥27 kg m − 2 . Thus, the study did not include Asian patients who qualify for treatment with obesity medications at lower BMI and WC cutoff points according to guidelines in their countries 29 . We observed that Asian patients were less likely to be in the higher BMI categories of SELECT and that the population of those with BMI <30 kg m − 2 had a higher percentage of Asian race. Asian individuals would probably benefit from weight loss and medication approaches undertaken at lower BMI levels in the secondary prevention of CVD. Future studies should evaluate CV risk reduction in Asian individuals with high CV risk and BMI <27 kg m − 2 . Another limitation is the lack of information on body composition, beyond the anthropometric measures we used. It would be meaningful to have quantitation of fat mass, lean mass and muscle mass, especially given the wide range of body size in the SELECT population.

An interesting observation from this SELECT weight loss data is that when BMI is ≤30 kg m − 2 , weight loss on a percentage basis is less than that observed across higher classes of BMI severity. Furthermore, as BMI exceeds 30 kg m − 2 , weight loss amounts are more similar for class I, II and III obesity. This was also observed in Look AHEAD, a lifestyle intervention study for weight loss 30 . The proportion (percentage) of weight loss seems to be less, on average, in the BMI <30 kg m − 2 category relative to higher BMI categories, despite their receiving of the same treatment and even potentially higher exposure to the drug for weight loss 30 . Weight loss cannot continue indefinitely. There is a plateau of weight that occurs after weight loss with all treatments for weight management. This plateau has been termed the ‘set point’ or ‘settling point’, a body weight that is in harmony with the genetic and environmental determinants of body weight and adiposity 31 . Perhaps persons with BMI <30 kg m − 2 are closer to their settling point and have less weight to lose to reach it. Furthermore, the cardiometabolic benefits of weight loss are driven by reduction in the abnormal ectopic and visceral depots of fat, not by reduction of subcutaneous fat stores in the hips and thighs. The phenotype of cardiometabolic disease but lower BMI (<30 kg m − 2 ) may be one where reduction of excess abnormal and dysfunctional body fat does not require as much body mass reduction to achieve health improvement. We suspect this may be the case and suggest further studies to explore this aspect of weight-loss physiology.

In conclusion, this analysis of the SELECT study supports the broad use of once-weekly subcutaneous semaglutide 2.4 mg as an aid to CV event reduction in individuals with overweight or obesity without diabetes but with preexisting CVD. Semaglutide 2.4 mg safely and effectively produced clinically significant weight loss in all subgroups based on age, sex, race, glycemia, renal function and anthropometric categories. Furthermore, the weight loss was sustained over 4 years during the trial.

Trial design and participants

The current work complies with all relevant ethical regulations and reports a prespecified analysis of the randomized, double-blind, placebo-controlled SELECT trial ( NCT03574597 ), details of which have been reported in papers describing study design and rationale 32 , baseline characteristics 24 and the primary outcome 21 . SELECT evaluated once-weekly subcutaneous semaglutide 2.4 mg versus placebo to reduce the risk of major adverse cardiac events (a composite endpoint comprising CV death, nonfatal myocardial infarction or nonfatal stroke) in individuals with established CVD and overweight or obesity, without diabetes. The protocol for SELECT was approved by national and institutional regulatory and ethical authorities in each participating country. All patients provided written informed consent before beginning any trial-specific activity. Eligible patients were aged ≥45 years, with a BMI of ≥27 kg m − 2 and established CVD defined as at least one of the following: prior myocardial infarction, prior ischemic or hemorrhagic stroke, or symptomatic peripheral artery disease. Additional inclusion and exclusion criteria can be found elsewhere 32 .

Human participants research

The trial protocol was designed by the trial sponsor, Novo Nordisk, and the academic Steering Committee. A global expert panel of physician leaders in participating countries advised on regional operational issues. National and institutional regulatory and ethical authorities approved the protocol, and all patients provided written informed consent.

Study intervention and patient management

Patients were randomly assigned in a double-blind manner and 1:1 ratio to receive once-weekly subcutaneous semaglutide 2.4 mg or placebo. The starting dose was 0.24 mg once weekly, with dose increases every 4 weeks (to doses of 0.5, 1.0, 1.7 and 2.4 mg per week) until the target dose of 2.4 mg was reached after 16 weeks. Patients who were unable to tolerate dose escalation due to AEs could be managed by extension of dose-escalation intervals, treatment pauses or maintenance at doses below the 2.4 mg per week target dose. Investigators were allowed to reduce the dose of study product if tolerability issues arose. Investigators were provided with guidelines for, and encouraged to follow, evidence-based recommendations for medical treatment and lifestyle counseling to optimize management of underlying CVD as part of the standard of care. The lifestyle counseling was not targeted at weight loss. Additional intervention descriptions are available 32 .

Sex, race, body weight, height and WC measurements

Sex and race were self-reported. Body weight was measured without shoes and only wearing light clothing; it was measured on a digital scale and recorded in kilograms or pounds (one decimal with a precision of 0.1 kg or lb), with preference for using the same scale throughout the trial. The scale was calibrated yearly as a minimum unless the manufacturer certified that calibration of the weight scales was valid for the lifetime of the scale. Height was measured without shoes in centimeters or inches (one decimal with a precision of 0.1 cm or inches). At screening, BMI was calculated by the electronic case report form. WC was defined as the abdominal circumference located midway between the lower rib margin and the iliac crest. Measures were obtained in a standing position with a nonstretchable measuring tape and to the nearest centimeter or inch. The patient was asked to breathe normally. The tape touched the skin but did not compress soft tissue, and twists in the tape were avoided.

The following endpoints relevant to this paper were assessed at randomization (week 0) to years 2, 3 and 4: change in body weight (%); proportion achieving weight loss ≥5%, ≥10%, ≥15% and ≥20%; change in WC (cm); and percentage change in WHtR (cm cm −1 ). Improvement in BMI category (defined as being in a lower BMI class) was assessed at week 104 compared with baseline according to BMI classes: healthy (BMI <25 kg m − 2 ), overweight (25 to <30 kg m − 2 ), class I obesity (30 to <35 kg m − 2 ), class II obesity (35 to <40 kg m − 2 ) and class III obesity (≥40 kg m − 2 ). The proportions of individuals with BMI <35 or ≥35 kg m − 2 who achieved sex- and race-specific cutoff points for WC (indicating increased metabolic risk) were evaluated at week 104. The WC cutoff points were as follows: Asian women <80 cm, non-Asian women <88 cm, Asian men <88 cm and non-Asian men <102 cm.

Overall, 97.1% of the semaglutide group and 96.8% of the placebo group completed the trial. During the study, 30.6% of those assigned to semaglutide did not complete drug treatment, compared with 27.0% for placebo.

Statistical analysis

The statistical analyses for the in-trial period were based on the intention-to-treat principle and included all randomized patients irrespective of adherence to semaglutide or placebo or changes to background medications. Continuous endpoints were analyzed using an analysis of covariance model with treatment as a fixed factor and baseline value of the endpoint as a covariate. Missing data at the landmark visit, for example, week 104, were imputed using a multiple imputation model and done separately for each treatment arm and included baseline value as a covariate and fit to patients having an observed data point (irrespective of adherence to randomized treatment) at week 104. The fit model is used to impute values for all patients with missing data at week 104 to create 500 complete data sets. Rubin’s rules were used to combine the results. Estimated means are provided with s.e.m., and estimated treatment differences are provided with 95% CI. Binary endpoints were analyzed using logistic regression with treatment and baseline value as a covariate, where missing data were imputed by first using multiple imputation as described above and then categorizing the imputed data according to the endpoint, for example, body weight percentage change at week 104 of <0%. Subgroup analyses for continuous and binary endpoints also included the subgroup and interaction between treatment and subgroup as fixed factors. Because some patients in both arms continued to be followed but were off treatment, we also analyzed weight loss by first on-treatment group (observation period until first time being off treatment for >35 days) to assess a more realistic picture of weight loss in those adhering to treatment. CIs were not adjusted for multiplicity and should therefore not be used to infer definitive treatment effects. All statistical analyses were performed with SAS software, version 9.4 TS1M5 (SAS Institute).

Reporting summary

Further information on research design is available in the Nature Portfolio Reporting Summary linked to this article.

Data availability

Data will be shared with bona fide researchers who submit a research proposal approved by the independent review board. Individual patient data will be shared in data sets in a deidentified and anonymized format. Information about data access request proposals can be found at https://www.novonordisk-trials.com/ .

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Acknowledgements

Editorial support was provided by Richard Ogilvy-Stewart of Apollo, OPEN Health Communications, and funded by Novo Nordisk A/S, in accordance with Good Publication Practice guidelines ( www.ismpp.org/gpp-2022 ).

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Donna H. Ryan

Department of Internal Medicine/Endocrinology and Peter O’ Donnell Jr. School of Public Health, University of Texas Southwestern Medical Center, Dallas, TX, USA

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Contributions

D.H.R., I.L. and S.E.K. contributed to the study design. D.B.H., I.L., D.D., A.K., S.M.M., A.P.v.B., C.C. and J.P.H.W. were study investigators. D.B.H., I.L., D.D., A.K., S.M.M., A.P.v.B., C.C. and J.P.H.W. enrolled patients. D.H.R. was responsible for data analysis and manuscript preparation. All authors contributed to data interpretation, review, revisions and final approval of the manuscript.

Corresponding author

Correspondence to Donna H. Ryan .

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Competing interests.

D.H.R. declares having received consulting honoraria from Altimmune, Amgen, Biohaven, Boehringer Ingelheim, Calibrate, Carmot Therapeutics, CinRx, Eli Lilly, Epitomee, Gila Therapeutics, IFA Celtics, Novo Nordisk, Pfizer, Rhythm, Scientific Intake, Wondr Health and Zealand Pharma; she declares she received stock options from Calibrate, Epitomee, Scientific Intake and Xeno Bioscience. I.L. declares having received research funding (paid to institution) from Novo Nordisk, Sanofi, Mylan and Boehringer Ingelheim. I.L. received advisory/consulting fees and/or other support from Altimmune, AstraZeneca, Bayer, Biomea, Boehringer Ingelheim, Carmot Therapeutics, Cytoki Pharma, Eli Lilly, Intercept, Janssen/Johnson & Johnson, Mannkind, Mediflix, Merck, Metsera, Novo Nordisk, Pharmaventures, Pfizer, Regeneron, Sanofi, Shionogi, Structure Therapeutics, Target RWE, Terns Pharmaceuticals, The Comm Group, Valeritas, WebMD and Zealand Pharma. J.D. declares having received consulting honoraria from Amgen, Boehringer Ingelheim, Merck, Pfizer, Aegerion, Novartis, Sanofi, Takeda, Novo Nordisk and Bayer, and research grants from British Heart Foundation, MRC (UK), NIHR, PHE, MSD, Pfizer, Aegerion, Colgate and Roche. S.E.K. declares having received consulting honoraria from ANI Pharmaceuticals, Boehringer Ingelheim, Eli Lilly, Merck, Novo Nordisk and Oramed, and stock options from AltPep. B.B. declares having received honoraria related to participation on this trial and has no financial conflicts related to this publication. H.M.C. declares being a stockholder and serving on an advisory panel for Bayer; receiving research grants from Chief Scientist Office, Diabetes UK, European Commission, IQVIA, Juvenile Diabetes Research Foundation and Medical Research Council; serving on an advisory board and speaker’s bureau for Novo Nordisk; and holding stock in Roche Pharmaceuticals. C.C. declares having received consulting honoraria from Novo Nordisk, Eli Lilly, Merck, Brace Pharma and Eurofarma. D.D. declares having received consulting honoraria from Novo Nordisk, Eli Lilly, Boehringer Ingelheim and AstraZeneca, and received research grants through his affiliation from Novo Nordisk, Eli Lilly, Boehringer Ingelheim and Rhythm. D.B.H. declares having received research grants through her academic affiliation from Novo Nordisk and Eli Lilly, and advisory/consulting honoraria from Novo Nordisk, Eli Lilly and Gelesis. A.K. declares having received research grants through his affiliation from Novo Nordisk and Pharmaserve Lilly, and consulting honoraria from Pharmaserve Lilly, Sanofi-Aventis, Novo Nordisk, MSD, AstraZeneca, ELPEN Pharma, Boehringer Ingelheim, Galenica Pharma, Epsilon Health and WinMedica. A.M.L. declares having received honoraria from Novo Nordisk, Eli Lilly, Akebia Therapeutics, Ardelyx, Becton Dickinson, Endologix, FibroGen, GSK, Medtronic, Neovasc, Provention Bio, ReCor, BrainStorm Cell Therapeutics, Alnylam and Intarcia for consulting activities, and research funding to his institution from AbbVie, Esperion, AstraZeneca, CSL Behring, Novartis and Eli Lilly. S.M.M. declares having received consulting honoraria from Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Daichii-Sankyo, esanum, Gilead, Ipsen, Eli Lilly, Novartis, Novo Nordisk, Sandoz and Sanofi; he declares he received research grants from AstraZeneca, Eli Lilly and Novo Nordisk. J.P. declares having received consulting honoraria from Altimmune, Amgen, Esperion, Merck, MJH Life Sciences, Novartis and Novo Nordisk; he has received a grant, paid to his institution, from Boehringer Ingelheim and holds the position of Director, Preventive Cardiology, at Brigham and Women’s Hospital. A.P.v.B. is contracted via the University of Groningen (no personal payment) to undertake consultancy for Novo Nordisk, Eli Lilly and Boehringer Ingelheim. J.P.H.W. is contracted via the University of Liverpool (no personal payment) to undertake consultancy for Altimmune, AstraZeneca, Boehringer Ingelheim, Cytoki, Eli Lilly, Napp, Novo Nordisk, Menarini, Pfizer, Rhythm Pharmaceuticals, Sanofi, Saniona, Tern Pharmaceuticals, Shionogi and Ysopia. J.P.H.W. also declares personal honoraria/lecture fees from AstraZeneca, Boehringer Ingelheim, Medscape, Napp, Menarini, Novo Nordisk and Rhythm. R.F.K. declares having received consulting honoraria from Novo Nordisk, Weight Watchers, Eli Lilly, Boehringer Ingelheim, Pfizer, Structure and Altimmune. E.B., G.K.H., O.K.J. and T.K.O. are employees of Novo Nordisk A/S.

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Extended data

Extended data fig. 1 effect of semaglutide treatment or placebo on waist circumference from baseline to week 104 by subgroups..

Data from the in-trial period. N  = 17,604. P values represent test of no interaction effect. P values are two-sided and not adjusted for multiplicity. The dots show estimated treatment differences and the error bars show 95% confidence intervals. Details of the statistical models are available in Methods . BMI, body mass index; CI, confidence interval; CV, cardiovascular; CVD, cardiovascular disease; eGFR, estimated glomerular filtration rate; ETD, estimated treatment difference; HbA1c, glycated hemoglobin; MI, myocardial infarction; PAD, peripheral artery disease; sema, semaglutide.

Supplementary information

Reporting summary, supplementary tables 1 and 2.

Supplementary Table 1. Baseline characteristics by BMI class. Data are represented as number and percentage of patients. Renal function categories were based on the eGFR as per Chronic Kidney Disease Epidemiology Collaboration. Albuminuria categories were based on UACR. Smoking was defined as smoking at least one cigarette or equivalent daily. The category ‘Other’ for CV inclusion criteria includes patients where it is unknown if the patient fulfilled only one or several criteria and patients who were randomized in error and did not fulfill any criteria. Supplementary Table 2. SAEs according to baseline BMI category. P value: two-sided P value from Fisher’s exact test for test of no difference.

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Ryan, D.H., Lingvay, I., Deanfield, J. et al. Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial. Nat Med (2024). https://doi.org/10.1038/s41591-024-02996-7

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DOI : https://doi.org/10.1038/s41591-024-02996-7

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Zantac Not a Cause of Woman’s Cancer, Jury Says in First Trial Over Drug

FILE PHOTO: Zantac heartburn pills are seen in this picture illustration taken October 1, 2019. REUTERS/Brendan McDermid/Illustration/File Photo

By Diana Novak Jones

CHICAGO (Reuters) - A jury in Chicago on Thursday rejected an Illinois woman’s claim that the now discontinued heartburn drug Zantac caused her colon cancer, in the first trial out of thousands of lawsuits making similar allegations.

The jury in Cook County, Illinois circuit court agreed with arguments from drugmakers GSK and Boehringer Ingelheim that the plaintiff, 89-year-old Illinois resident Angela Valadez, had not proven her colon cancer was at least in part caused by her Zantac use.

Valadez had alleged that her cancer was a result of taking over-the-counter Zantac and generic versions of it from 1995 to 2014. The lawsuits over the drug say its active ingredient, ranitidine, under some conditions turns into a cancer-causing substance called NDMA.

Attorneys for Valadez had asked the jury to award $640 million for her suffering. The judge rejected Valadez's request to seek punitive damages during the trial, according to her attorneys.

Mikal Watts, one of Valadez's attorneys, said he respected the jury's verdict but was confident the companies would be held liable in future Zantac trials. "This is a marathon, not a sprint," he said.

Both GSK and Boehringer said in statements that the verdict was consistent with scientific evidence that Zantac does not cause cancer, and that they would vigorously defend themselves against future claims.

Britain-based GSK, whose predecessor developed the drug but later sold the brand to other companies, and German drugmaker Boehringer Ingelheim, which sold the medicine from 2006 until 2017, were the only defendants in the trial after the other companies settled.

Watts said at the trial that began on May 2 that the companies knew that ranitidine would turn into NDMA as it aged or was exposed to extreme temperatures, but did not ensure it was properly handled by transporters, distributors and stores.

Attorneys for GSK and Boehringer countered that Zantac has been repeatedly proven to be safe and effective and that no scientific or medical study has connected Zantac to cancer.

The companies attorneys also argued at trial that there was no evidence to support Valadez's claim that she had taken Zantac for 18 years, and that she had a host of risk factors that made her more likely to develop colon cancer.

The jury found that Valadez proved that she had taken Zantac, but not that it was a cause of her cancer.

First approved in 1983, Zantac became the world's best selling medicine in 1988 and one of the first-ever to top $1 billion in annual sales.

In 2020, the U.S. Food and Drug Administration asked drugmakers to pull Zantac and its generic versions off the market after NDMA was found in samples of the drug. Thousands of lawsuits began piling up in federal and state courts.

The defendants notched a significant win in 2022, when a judge dismissed about 50,000 claims centralized in federal court in Florida. That judge concluded that the opinions of the plaintiffs' expert witnesses that Zantac can cause cancer were not supported by sound science.

Some of the claimants in those cases are appealing the ruling to the Atlanta, Georgia-based 11th U.S. Circuit Court of Appeals.

A judge in Delaware state court is weighing the fate of about 72,000 cases, the bulk of those remaining, where the drugmakers similarly argue that plaintiffs' expert testimony should be kept out.

Some other cases were previously settled, including several individual cases just before trial, and about 4,000 state court lawsuits outside of Delaware against Sanofi, which has owned the right to sell Zantac over the counter since 2017.

Earlier this month, the Financial Times reported that Pfizer had struck a deal to pay up to $250 million to settle more than 10,000 Zantac lawsuits.

Sanofi now sells Zantac360, a reformulated heartburn medicine whose active ingredient is famotidine.

(Reporting By Diana Novak Jones in Chicago, Brendan Pierson in New York; Editing by Bill Berkrot and Alexia Garamfalvi)

Copyright 2024 Thomson Reuters .

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