A divided Federal Circuit panel held that a district court abused its discretion when it excluded an expert’s opinions as being contradictory to the district court’s claim construction order. In Barry v. DePuy Synthes Cos., Appeal Nos. 2023-2226, -2234 (Fed. Cir. Jan. 20, 2026), the Federal Circuit held that the expert’s opinions reflected his application of the district court’s construction rather than an attempt to change that construction.
Procedural Background
The Barry appeal arrived at the Federal Circuit after the district court (the United States District Court for the Eastern District of Pennsylvania) granted DePuy’s motion for judgment of non-infringement as a matter of law. That motion was based on the argument that the opinions of Barry’s infringement expert, Dr. Walid Yassir, were based on an understanding of the claim term “handle means” that was inconsistent with the district court’s construction of that term. Specifically, the court had construed the term to mean “a part that is designed especially to be grasped by the hand.” In the district court’s view, certain of Dr. Yassir’s testimony indicated he applied a different construction. For example, DePuy’s counsel elicited testimony from Dr. Yassir on cross-examination that indicated Dr. Yassir treated the term “handle means” to cover “parts that cannot be assembled without grasping them by the hand.” The district court thus struck Dr. Yassir’s testimony and, because the record then failed to include sufficient evidence to support a jury verdict of infringement, granted DePuy’s JMOL on the issue.
The Federal Circuit Majority Decision
A split panel of the Federal Circuit reversed. Circuit Judge Stark, joined by Circuit Judge Taranto, concluded that the district court abused its discretion in excluding Dr. Yassir’s testimony and granting JMOL in favor of DePuy. Central to the majority’s decision was its finding that Dr. Yassir’s testimony did not contradict the district court’s claim construction but was instead an “application” of that construction. The majority noted that Dr. Yassir repeatedly testified on direct that his opinions were rendered pursuant to the district court’s construction. The majority stated that “disputes over the application of the court’s construction are fact disputes to be resolved by the factfinder, not evidentiary issues to be decided by the court in its role as gatekeeper.” In addressing Dr. Yassir’s cross-examination testimony, which the district court found to reflect a divergent claim construction, the majority stated, “At most, what the cross-examination revealed was a dispute as to the credibility of Yassir’s repeated insistence that he did, in fact, apply the court’s construction.”
The majority further explained why the district court too aggressively wielded its gatekeeping power stating that an effective cross-examination will almost always reveal “tensions and ambiguities” but that those are different than impermissible “contradictions.” As the majority stressed, “contradiction does not mean mere tension, arguable inconsistency, or lack of persuasiveness.” Relatedly, the majority expressed fear that district courts would dismantle parties’ cases based on “ordinary evidentiary imperfections” at trial.
Accordingly, the Federal Circuit reversed the grating of JMOL and the exclusion of Dr. Yassir’s testimony and remanded for a new trial.
Dissent
The district court did not err in the view of Circuit Judge Prost who dissented. The dissent noted the Advisory Committee’s view that district courts had, prior to the 2023 amendments to Federal Rule of Evidence 702, too often treated “the critical questions of the sufficiency of an expert’s basis, and the application of the expert’s methodology, [as] questions of weight and not admissibility.” In the dissent’s view, the majority opinion is subject to that same critique.
Conclusion
Under Barry, parties seeking to exclude the testimony of an opposing party’s expert as being contrary to the court’s claim construction should focus on how that testimony is contradictory to, rather than merely in tension with, that construction. At the same time, parties should ensure their experts’ consistently apply a court’s construction and do not agree to alternative definitions. As the divided panel of Barry reflects, there is no universal understanding as to the line between excusable applications of a construction and fatal contradictions to a construction.