Product liability claims require proof of causation. To be sure, they also require proof of some defect in the product and/or its accompanying warnings and product literature. But defect and causation are separate elements of a prima facie claim, and both must be established – usually, through expert testimony. As we have discussed on multiple occasions (for example, here and here), a plaintiff’s failure to offer admissible expert testimony on each element can lead to summary judgment. A recent decision from the Eastern District of Pennsylvania offers yet another illustration.
In Slatowski v. Sig Sauer, Inc., 2024 WL 1078198 (E.D. Pa. Mar. 12, 2024), the plaintiff was an Immigration and Customs Enforcement (“ICE”) officer who was injured when his pistol fired unintentionally during a marksmanship training exercise. He sued the gun manufacturer, alleging that a design defect in the gun’s integral safety feature – specifically, the lack of a tabbed trigger – caused the firearm to discharge unintentionally. The plaintiff proffered two experts in support of the claim: a gunsmith and a certified firearms instructor and range safety officer with a Ph.D. in ergonomics. The defendant moved to exclude both experts’ opinions and also moved for summary judgment, arguing that the plaintiff had no admissible expert testimony to establish causation.
The court began by confirming that the plaintiff would need expert testimony to establish causation. The plaintiff argued that a lay jury could understand the difference between pulling on a tabbed trigger and the trigger in the pistol at issue. However, the court ruled that the internal mechanics of a pistol were complex and therefore required expert testimony to understand the technical subject matter. As such, Plaintiff’s claims could not move forward without expert testimony establishing causation.
The plaintiff’s expert gunsmith opined that the lack of a tabbed trigger on the pistol at issue rendered it defective. He had examined the plaintiff’s pistol, viewed YouTube videos of unintentional discharges involving the same model, evaluated data published by ICE regarding other incidents, and suggested a competitor pistol as a safer alternative design due to its tabbed trigger. The problem was that he had no basis on which to opine that a tabbed trigger would have prevented the unintentional discharge in the plaintiff’s case – that is, that what he called a “defect” had actually caused the plaintiff’s injuries. Although he assumed that the trigger had been actuated by “a finger [or] by an object [or] by something,” he did not know what had actuated the trigger or even what holster the pistol was in when it discharged. Moreover, he had tested a pistol of the same model as the plaintiff’s but could not simulate the pistol firing unintentionally or the circumstances in which the plaintiff’s pistol discharged. Nor could he say that a tabbed trigger would not have fired under the same circumstances – that is, that the injuries would have been avoided if the pistol had not had the “defect” to which he pointed.
The court found that the expert’s opinions missed the mark, noting that he did not attempt to replicate or simulate the conditions in which the plaintiff unholstered the gun. The expert provided no basis for his ipse dixit conclusion that the plaintiff’s pistol would not have intentionally discharged had it been equipped with a tabbed trigger safety function. Because his opinions were descriptive in nature with little to no scientific analysis, they were inadmissible.
Plaintiff’s second expert fell for largely the same reason, relying on largely the same evidence and offering similar – and similarly deficient – opinions. He opined that a tabbed trigger would have avoided the unintentional discharge because, without that safeguard, “the sides of the [pistol] can be used to engage the trigger or activate the trigger. It doesn’t have to be pulled with your finger directly on the fact.” But he had no opinion as to what had contacted the trigger in the plaintiff’s case, or what part of the trigger was contacted, or whether the pistol had fired without any trigger movement. Nor had he conducted any testing to determine whether a tab trigger could have been pulled under the circumstances of the accident. The court rejected the expert’s causation opinion as unsupported by studies, scientific analyses, methodology, or explanations to support his conclusion. Because the opinion rested solely on the expert’s own intuitions, it was inadmissible. And, because the plaintiff therefore had no expert testimony to support causation, the court granted the defendant’s motion for summary judgment.
In essence, the experts in Slatowski assumed that the existence of a defect – as they saw it – implicitly proved causation. They were mistaken; one cannot prove that a defect is to blame for a specific outcome in a plaintiff’s case merely by proving that the defect exists. Rather, causation is a separate and distinct element. Slatowski’s discussion of whether causation had to be supported by expert testimony hints at a similar blending of the concepts of defect and causation – plaintiff argued that a jury could understand simply placing a tab on a trigger, but the court effectively responded that the question of causation requires not only the ability to appreciate how a proposed alternative design differs but an understanding of how the mechanism in question functions within the complex setting of a pistol. Ultimately, Slatowski is a good illustration of a court keeping the individual elements of a claim separate and demanding that a plaintiff properly support each element with admissible expert evidence.
