In this patent infringement action, the plaintiffs sought to exclude the defendant’s expert on invalidity and infringement. One of the grounds on which they sought to exclude the testimony was based on bias. The plaintiffs contended that the expert’s bias stemmed from his belief that he invented certain of the technology at issue, which the plaintiffs disputed and which they asserted would motivate him to form opinions that are not based on facts.
In analyzing the issue, the district court noted that “[a]n expert’s alleged bias, however, is not a proper basis on which to exclude his or her testimony under Daubert or Rule 702. See Cage v. City of Chicago, 979 F. Supp. 2d 787, 827 (N.D. Ill. 2013) (collecting cases); Baldwin Graphic Sys., Inc. v. Siebert, Inc., No. 03 C 7713, 2005 WL 4034698, at *3 n.3 (N.D. Ill. Dec. 21, 2005) (“[A]lleged bias is fodder for cross-examination and impeachment, not a ground for exclusion [of expert testimony].”). Any bias on the part of a witness would go to the weight of a specific opinion, not to its admissibility. See Cage, 979 F. Supp. 2d at 827 (citing DiCarlo v. Keller Ladders, Inc., 211 F.3d 465, 468 (8th Cir. 2000)).
Accordingly, the district court denied the plaintiffs’ motion to exclude the expert’s testimony on invalidity and infringement.
Neurografix v. Brainlab, Inc., Case No. 12 C 6075 (E.D. Ill. July 6, 2020) Continue reading