Montana Lawyer October/November 2025

New Data on Jurors and Proximate Cause THOMAS M. O’TOOLE, PH.D & KEVIN R. BOULLY, PH.D JURY ECONOMICS

Last year, we wrote about the growing importance of proxi mate cause arguments. When we both entered this profession over twenty years ago, attorneys told us cases could not be won or lost on proximate cause. What seemed specious at the time has since been proven definitively wrong. As recently as May of this year on one of our cases, a jury found in favor of the defense on proximate cause in a significant personal injury case despite finding the defendant negligent. When asked after trial, one of the jurors explained that they did not like the defen dant’s conduct and wanted to send a message to the defendant that it should change its conduct by finding it negligent, but ultimately did not believe that negligent conduct was a cause of injury to the plaintiff. We have seen similar verdicts in recent years, all demonstrating jurors’ willingness to carefully scruti nize proximate cause arguments. Our previous column on proximate cause focused on what we have learned anecdotally through our mock trials and shadow jury projects over the years. Unsatisfied with anecdotal experience alone, Sound Jury Consulting conducted a nation wide study this year of over 800 mock jurors to collect data on how jurors evaluate proximate cause arguments. The study posed two primary questions: 1) Does the way in which defense attorneys talk about proximate cause impact how jurors evalu ate it? and 2) Does the structure of the verdict form impact how jurors evaluate proximate cause? Finally, this study revealed some of the key hurdles that explain why proximate cause argu ments by defendants are not always effective. In this month’s column, we share the results of this study. The study used the case of an automobile accident where a delivery driver, who was going 10 mph over the speed limit, hit a patch of ice in the road, lost control of the delivery truck, and struck an oncoming vehicle, causing the plaintiffs’ neck and back injuries. Participants were told that while the temperature was below freezing, there had been no precipitation in the two weeks leading up to the accident. Instead, the ice was caused by a pipe that burst at the strip mall along the road, causing water to cover the street, which then froze. In other words, the delivery driver had no notice – no reason to believe there might be ice present in the road. Finally, the participants were told the experts will testify that while the delivery driver was going 10 mph over the speed limit, his speed would not have made a meaningful difference in his ability to maintain control of his vehicle when it struck the ice and would not have significantly changed the force of the impact on the plaintiff’s vehicle. In short, the driver had no notice and his speed was irrelevant. The participants listened to arguments from both the plaintiff and the defendant and completed a verdict form and a questionnaire after hearing each sides’ arguments. The research tested two variables. First, some participants completed a ver dict form that had negligence and proximate cause as separate

questions while others completed verdict forms that had them merged into a single question, the latter of which is common in many venues outside of Washington state. Second, some par ticipants heard defense arguments that explained in great detail how proximate cause works and why they should not find in favor of the plaintiff on proximate cause even if they believe the defense was negligent. We will refer to this as the “explicit prox imate cause argument.” Others heard a much simpler version, more akin to what we often see at trial, where the defendant argued that the speed of the driver did not make a difference in what happened so the participants should not find the defense liable for the plaintiff’s injuries. Across all scenarios, the plaintiff was signifi cantly more likely to prevail on proximate cause when negligence and proximate cause were broken out into separate questions on the verdict form. We will start with the study’s most interesting and shock ing finding. Across all scenarios, the plaintiff was significantly more likely to prevail on proximate cause when negligence and proximate cause were broken out into separate questions on the verdict form. In both variations of an explicit proximate cause argument by the defense and the general argument, participants were significantly more likely to find in favor of the plaintiff on proximate cause when the questions were separated on the verdict form. Even when provided the explicit proximate cause argument by the defense, participants were 20% more likely to find in favor of the plaintiff on proximate cause if they com pleted a verdict form that had the separate questions than if they completed the verdict form with negligence and causation merged into a single question. These results are contrary to what most would expect. We have often heard folks in our industry tell defense attorneys to request a verdict form that has the elements separated into two questions rather than combined into a single question, with the goal of forcing discussion on proximate cause, but this research suggests such a recommendation might be counter productive. To better understand this result, we went back and watched recordings of several mock jury deliberations where proximate cause was an issue raised by the defense. Watching deliberations in cases where the issues were separated on the verdict form, it stood out that having these questions separated forced a lengthier discussion on negligence, which meant the plaintiff was able to build early momentum in deliberations before the jury even got to the proximate cause argument that favored the defendant. The focus on the bad negligence facts for the defendant also generated anger early in the discussion that cut against motivation to let the defendant “off the hook”

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