Defining the Limits of Lay Testimony in Complicated Products Cases

“So when is a question too complicated for the jury?” That is the question the Third Circuit sought to answer recently in Slatowski v. Sig Sauer, Inc., ___ F. 4th ___, 2025 WL 2178533 (3d Cir. 2025), reversing a district court’s grant of summary judgment despite affirming its exclusion of the plaintiff’s causation experts. Ironically, the Third Circuit’s analysis of when an expert opinion is required is itself so nuanced that it may require expert interpretation. Upon close inspection, the Slatowski panel’s holding is not nearly as broad as the headings might suggest.