WLF Urges Federal Circuit to Grant Rehearing En Banc to Restore Rule 702 Gatekeeping

“District judges must serve as gatekeepers to exclude unreliable expert testimony before it reaches the jury.”
—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 Federal Circuit to grant rehearing en banc in an important patent dispute. In its amicus brief, WLF contends that a divided panel decision—by treating challenges to an expert’s factual and methodological foundations as issues of weight rather than admissibility—undermines Rule 702 and the Federal Circuit’s recent EcoFactor en banc ruling.

The case arises from a patent infringement action in which the district court excluded two of the plaintiff’s expert opinions—one inconsistent with the court’s claim construction and the other riddled with methodological gaps—and entered judgment as a matter of law in favor of DePuy Synthes. A divided Federal Circuit panel reversed, holding that such reliability flaws should be left for the jury to weigh in the “adversary process.”

WLF’s brief argues that the panel majority’s approach revives the defunct “weight-not-admissibility” framework that EcoFactor and the 2023 Rule 702 amendments both squarely rejected. WLF warns that allowing unreliable expert testimony to reach juries will invite junk science into complex patent cases, chill proper gatekeeping by trial judges, and erode confidence in verdicts. WLF urges the Court to grant rehearing en banc to reaffirm that scientific reliability is a question for district courts, not juries.