WLF Urges Fourth Circuit to Affirm Exclusion of Unreliable Expert Testimony in Product Liability Case
“Unreliable expert evidence threatens the integrity of federal judicial proceedings and produces unfair outcomes.”
—Cory Andrews, WLF General Counsel & Vice President of Litigation
Click here for WLF’s brief.
(Washington, DC)—Washington Legal Foundation (WLF) today urged the U.S. Court of Appeals for the Fourth Circuit to affirm a district court’s exclusion of a plaintiff’s expert testimony in a product liability case, which resulted in summary judgment for the defendant. WLF’s amicus brief contends that the district court correctly applied amended Rule 702 by barring unqualified and unreliable opinions that threatened to mislead the jury and circumvent judicial gatekeeping.
The case arises from plaintiff Jack Anthony Williams’s allegation that his Sig Sauer P320 pistol discharged without a trigger pull while holstered in his pocket, causing injury to his leg. Williams sued Sig Sauer and a related entity under North Carolina law for defective design, failure to warn, negligence, and related claims. To support his claims, he offered testimony from gunsmith Timothy Whealton and mechanical engineer Dr. Joshua Harrison. The district court excluded both experts’ testimony as unreliable and unqualified under Rule 702, then granted summary judgment for Sig Sauer because Williams could not establish causation without admissible expert evidence.
In its amicus brief, WLF argues that cross-examination cannot substitute for the district court’s mandatory gatekeeping duty under the 2023-amended Rule 702, which requires judges—not juries—to ensure expert opinions rest on sufficient facts, reliable principles, and proper application to the case facts by a preponderance of the evidence. The brief stresses that Williams improperly relies on superseded pre-amendment precedent treating methodological flaws and factual gaps as jury issues rather than admissibility barriers, while sister circuits have tightened standards post-amendment to exclude similarly speculative, untested, and disconnected opinions.