Fed Circ reverses Microsoft win excluding expert witness: Blaw

Fed Circ reverses Microsoft win excluding expert witness: Blaw

The U.S. Court of Appeals for the Federal Circuit recently reversed a lower court’s decision to exclude expert testimony in a patent infringement case, reinforcing the admissibility of expert opinions that apply a court’s claim construction and emphasizing that credibility disputes should be resolved by juries rather than judges according to the Federal Circuit's decision. In Barry v. DePuy Synthes Co., the Federal Circuit vacated the district court’s judgment as a matter of law (JMOL) of noninfringement, ruling that the exclusion of the patentee’s expert testimony was an abuse of discretion. The case centered on patents covering surgical tools for spinal deformity correction, with the court’s claim construction defining “handle means” as “a part designed especially to be grasped by the hand.” The patentee’s technical expert testified that the defendant’s products met this standard, despite cross-examination challenges suggesting his interpretation might apply broadly. The Federal Circuit clarified that such disagreements over application or persuasiveness do not justify exclusion unless there is a genuine contradiction of the court’s construction. Similarly, the court overturned the exclusion of a survey expert’s methodology-based testimony, noting that flaws in methodology typically affect evidence weight, not admissibility. By restoring the experts’ testimony, the Federal Circuit determined there was sufficient evidence to allow a jury to assess infringement. The decision underscores the importance of preserving expert testimony in patent litigation and limits judicial gatekeeping in credibility and methodology disputes as the Federal Circuit's decision demonstrates.