The US Court of Appeals for the Federal Circuit reversed an exclusion of expert testimony and grant of judgment as a matter of law, finding that the district court improperly conflated admissibility with credibility and weight of the evidence. Barry v. DePuy Synthes Companies, et al., Case Nos. 023-2226; -2234 (Fed. Cir. Jan. 20, 2026) (Prost, Taranto, Stark, JJ.) (Prost, J., dissenting).
Mark Barry owns patents covering surgical techniques and tools for treating spinal deformities. Barry sued DePuy alleging that DePuy induced surgeons to infringe the patents. The patents describe tools and methods, including levers, for applying force to vertebrae to realign the spinal column. Two of the patents required the presence of a “handle means,” which the district court construed as “a part that is designed especially to be grasped by the hand.”
At trial, Barry relied on two experts. His infringement expert, Dr. Walid Yassir, testified that DePuy’s accused tools could be assembled and used in infringing configurations and that certain components (or linked assemblies) constituted the claimed “handle means” under the court’s construction. Barry also offered expert testimony from Dr. David Neal, who conducted a surgeon survey to estimate how often DePuy’s tools were used in infringing configurations, which in turn supported Barry’s damages case.
Although the district court had denied DePuy’s pretrial Daubert motions regarding Barry’s experts, it reversed course mid-trial. The court excluded Yassir’s testimony on the ground that he contradicted the court’s claim construction by equating “handle means” with parts that must be grasped during assembly. The court also excluded Neal’s survey testimony, concluding that methodological flaws, such as nonprobability sampling and alleged defects in question design, rendered the survey unreliable. Having excluded both experts, the court granted DePuy judgment as a matter of law. Barry appealed.
The Federal Circuit agreed that expert opinion that contradicts a court’s claim construction would not be helpful to a jury and should be excluded under Rule 702. The Court found, however, that Yassir did not contradict the court’s construction but instead applied it in a manner a reasonable factfinder could accept or reject – a disputed application that DePuy challenged on cross-examination. However, DePuy did not object to Yassir’s direct testimony despite having secured a pretrial ruling barring evidence inconsistent with the claim construction.
The Federal Circuit concluded that Yassir’s testimony did not contradict the court’s claim construction but rather exposed areas of tension and potential weakness in how Yassir applied that construction to the accused devices. The Court explained that DePuy’s questioning elicited testimony about what could constitute a “handle means” that went to the credibility and persuasiveness of Yassir’s opinions, not their admissibility. The Court rejected the district court’s reliance on isolated testimonial snippets divorced from their surrounding explanations, noting that ordinary ambiguities and concessions revealed through adversarial questioning are for the jury to evaluate and do not convert an expert’s application of a claim construction into an impermissible contradiction warranting exclusion under Rule 702.
The Federal Circuit likewise held that the district court abused its discretion in excluding Neal’s survey. While acknowledging the district court’s concerns about representativeness and design, the Court found no evidentiary basis to conclude that the survey lacked the “good grounds” required under Rule 702. The Court reiterated that most survey criticisms (sampling choices, response rates, or question framing) are typically fodder for cross-examination rather than wholesale exclusion, absent a showing that the methodology is fundamentally unsound.
Because the judgment as a matter of law rested entirely on exclusion of the experts, the Federal Circuit also reversed that ruling and remanded for a new trial at which both experts may testify.
Judge Prost dissented. In her view, the district court properly exercised its gatekeeping role by excluding both experts. She emphasized that a court’s independent reliability determination is an “essential prerequisite” to the admission of expert testimony under Rule 702. Citing the Federal Circuit’s recent en banc decision in EcoFactor and the 2023 amendments to Rule 702, the dissent warned that treating foundational reliability issues as matters of weight for the jury undermines the court’s responsibility to ensure that expert opinions are supported by sufficient facts and reliable methodology. In Judge Prost’s view, Yassir’s testimony materially departed from the court’s claim construction, and Neal’s survey suffered from cumulative methodological flaws (particularly concerning representativeness and question design) such that the district court acted well within its discretion in excluding both experts and granting judgment as a matter of law.
Practice note: The decision highlights the Federal Circuit’s continued insistence that courts distinguish carefully between unreliable expert methodology that warrants exclusion and debatable expert conclusions, which must be assessed by the jury.
