By Thomas M. O'Toole, Ph.D. & Kevin Boully, Ph.D.
One of the most persistent beliefs about jury trials is that cases are won in opening statement. It is a belief largely born out of primacy theory, which is the idea that what jurors hear first at trial is most influential to their final verdict. The belief in opening statements as the key decision point for jurors has been repeated in publications, television series, movies, and endless CLE presentations. Harvard University Professor of Law Ronald S. Sullivan, Jr. recently wrote, “Though Hollywood movies about courtroom dramas often glamorize the closing arguments given by lawyers, in reality the opening statement is likely the most important single event of a trial.” Last year, a retired trial judge in California presented a CLE on “how to win your case in opening statement.” We hear it regularly from some of our own clients. But this profession, as smart as its members are, routinely embraces old wives’ tales, pop psychology gimmicks, and other beliefs that give attorneys that sense of control and belief that they are inching closer to success, so we wanted to explore the research on this issue and offer insights into whether cases are won in opening statements.
Before we get to our own study, let’s look at some of the research out there on this subject. If you conduct a Google search on the topic, you will find pages and pages of people making this claim with few, if any, citing research or data to support their argument. However, when data is offered, one of the most popular statistics we hear comes from the famous book The American Jury, which was published in 1967 by Harry Kalven Jr. and Hans Zeisel. First, Kalven and Zeisel conducted their extensive study that led to this book on criminal trials, which are notably different than civil trials. The unique difficulties facing criminal defendants at trial set criminal cases apart from the average civil case and it comes as no surprise that jurors make early judgments about criminal allegations. Even more important, when Hans Zeisel learned in the 1980s that people were suggesting his research found that most people make up their mind about opening statements, he published a clarifying article in a University of Chicago Law School publication that their research had no such finding, going as far as suggesting this argument about the “superpower” of opening statement is a “hoax.” He specifically stated, “we never made such a discovery; we never even asked the question. Nowhere in The American Jury’s 438 pages can one even find the words “opening statement.”
A 1981 study of criminal trials by Thomas Pyszczynksi and Lawrence Wrightsman found that jurors were more likely to maintain their initial leanings after opening statement throughout the trial. Notably, this study again focused on criminal cases which are uniquely different from civil cases but even the authors note that their findings were in conflict with other similar studies at the time, citing a 1972 study by Laurens Walker, John Thibaut, and Virginia Andreoli that found a greater recency effect at trial than a primacy effect. Walker, et al. conducted an interesting study where they presented 50 pieces of evidence to each participant but varied the order across participants. They found that the most recent piece of evidence participants heard tended to be the most influential, which implies closing arguments could be more impactful than opening statements.
Next up is a 2011 publication by Brian Bornstein and Edie Greene that is commonly cited to support the contention that cases are won in opening statements. Nowhere in this publication do the authors suggest that cases are won in opening statements or present data that suggests this. Instead, the authors argue the best predictor of final verdicts is the individual pre-deliberation verdicts, citing research that, “In approximately 90% of trials, the position favored by the majority at the beginning of deliberations becomes the jury verdict.” However, this data only suggest that verdicts may not change much over the course of deliberations from the initial majority. It tells us nothing about volatility in case leanings over the course of trial after opening statements.
In another study, fellow University of Kansas graduate Shelley Spiecker found in a study published with Debra Worthington in 2003 that there was interaction between the structure of opening statements and closing arguments by a party that directly impacted jury verdicts. In other words, they found that the style and structure of opening statement alone was not as impactful on final verdict as the combined style and structure of opening statements and closing arguments. They found this by using a research design that varied the structures of both the opening statements and closing arguments in a few different ways. While Spiecker and Worthington do not directly refute the suggestion that cases are won in opening, their data indirectly highlight the connection between opening and closing structures as impactful for the final verdict, meaning that opening statements do not singlehandedly impact the final verdicts.
Since the empirical research is inconsistent at best on the impact of opening statements, Sound Jury Consulting examined data collected from 430 mock jurors from 14 mock trials on civil cases conducted across the country in 2023 and 2024 to perhaps shed some light on whether cases can be won in opening statement. We realized we had a wealth of data that might shed light on whether jurors change their minds after opening statements. In each of these mock trials, the mock jurors were asked to indicate their leanings in the case both immediately before deliberations and immediately after deliberations. While these two data points do not directly address the impact of opening statement, they shed light on the lasting impact of opening statements. Specifically, changes in leanings over the course of deliberations directly refute the suggestion that jurors make up their mind after opening statements. If jurors do in fact make up their minds in opening statements, we should observe minimal, if any, changes from pre-deliberation to post-deliberation in our data.
So what did the data show? For starters, 49.8% indicated the same leaning after deliberations as they did before deliberations. Another 18% said their leaning towards the party they favored before deliberations strengthened over the course of deliberations. However, 26% changed the party they favored over the course of deliberations and another 6% said their leaning in favor of one party prior to deliberations weakened over the course of deliberations. One might argue from this that 68%–74% of the mock jurors favored the same party to some degree after deliberations as they did before deliberations, but this focus would miss a more important point since 68%–74% is not the decision rule. For example, in King County, 10 of the 12 jurors must agree and in the Western District of Washington, they all must agree. This makes deliberations meaningful and impactful since opening statements alone are not sufficient for achieving the verdict threshold.
However, there are two more important points about these research findings. First, this study examined mock trial data from fourteen different cases. When we compared the pre- and post-deliberation data on a case-by-case basis, we found a great deal of variance between cases. For example, in some cases, the percentage of mock jurors who changed their leaning over the course of deliberations was as low as 13%. In other cases, it was as high as 35%. We saw multiple cases where the combination of mock jurors who changed their party leanings and those who indicated that their leanings had weakened over the course of deliberations exceeded 50%. Consequently, the data suggests that any lasting impact of opening statement varies from case-to-case.
Second, and more important, is a unique social conformity dynamic we often see in mock trial research and post-trial interviews with actual jurors. We recently saw this phenomenon in a bad faith case against a large insurance company. In one group, we saw that five of the ten mock jurors favored the defense both before and after deliberations, yet this group voted 9–1 in favor of the plaintiff. Even more fascinating, the damage award of the group far exceeded what eight of the ten mock jurors had indicated in their pre-deliberation questionnaire they were willing to award the plaintiff, if they reached a decision where they were awarding money. What we realized as we went back and reviewed this group’s deliberations is that, while half the group favored the defense, they either struggled to effectively re-articulate the defense’s technical arguments, or they simply did not appear motivated to argue against three loud and dominating advocates for the plaintiff. In fact, when one of the defense-leaning mock jurors was asked in the post-deliberation group interview why he did not push for a defense verdict in deliberations, he talked about how even though he favored the defense, the defendant is an insurance company, and he does not like insurance companies. Consequently, he did not feel compelled to fight for his personal opinions in this case, especially in the face of three zealous plaintiff advocates who aggressively argued with anyone who highlighted points in favor of the defense.
In sum, while extensive research clearly demonstrates that opening statements are impactful, there is little to no research to support the notion that cases are “won” in opening statement. Since attorneys love pop psychology concepts, the one most relevant to this discussion is the sleeper effect. The sleeper effect helps explain the persistent myth that cases are won in opening statement despite the fact that there is little to no data to support the claim and there are in fact some recency studies that directly refute it. The sleeper effect says that messages can become detached from their original source over time, and gain credibility and acceptance where no such credibility and acceptance was justified by the original source. This seems to be the case with the idea that cases are won in the opening statement. The claim is ubiquitous in the legal profession but has become totally detached from any research or data actually supporting the claim. Perhaps even more shocking, is the lack of sufficient preparation for opening statement put forth by some of the attorneys who insist cases are won in openings, which gets us to perhaps a more important and accurate claim about opening statement: While you cannot “win” your case in opening statement, you can certainly lose it there.
Thomas M. O’Toole, Ph.D. is President of Sound Jury Consulting in Seattle, WA. Kevin R. Boully, Ph.D. is Senior Consultant at Perkins Coie in Denver, CO.
