Headwater Research LLC v. Verizon Communications Inc.
2:23-cv-00352
E.D. Tex.Jun 16, 2025Background
- Headwater Research LLC sued Verizon and affiliates, alleging infringement of four patents; one patent (’543) was dismissed by agreement.
- Plaintiff filed a motion to exclude opinions of Verizon's survey expert, Sarah Butler.
- Butler’s opinions rebutted technical and damages analyses of plaintiff’s technical expert, Dr. Wesel, particularly around consumer behavior and usage data.
- The motion argued Butler was unqualified to opine on technical issues, that her critiques of the underlying data went beyond her expertise, and that her consumer survey was improper rebuttal.
- The Court reviewed Butler’s report, plaintiff’s arguments, and Verizon’s defenses under the standard for expert admissibility (Rule 702/Fed. R. Evid.).
- The motion to exclude Butler’s opinions was denied in full.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Butler’s qualifications to critique technical analysis | Butler is not qualified to opine on technical testing and methodology | Butler opined only within her expertise (consumer surveys/behavior), not technical domains | Butler gave permissible opinions within her expertise; motion denied |
| Butler’s critique of use of Strategy Analytics data | Butler lacks experience in smartphone telemetry data; her critique goes beyond expertise | It doesn’t matter how data is collected; Butler critiqued the use of data to represent user profiles, which aligns with her expertise | Butler’s opinions concern consumer behavior profiles, not technical data collection; motion denied |
| Butler’s consumer survey as proper rebuttal | Survey not proper rebuttal since Wesel did not use surveys; introduces new evidence | Survey rebuts assumptions Wesel makes about consumer behavior that feed into damages analysis; rebuttal experts aren’t limited to the same methods | Survey is proper rebuttal to factual assumptions in plaintiff’s damages case; motion denied |
| Timeliness/ability to respond to survey | Plaintiff unable to address Butler’s survey due to timing | Plaintiff could have had their own survey expert; rebuttal timing applies equally to both parties | Survey’s timing not grounds for exclusion; motion denied |
Key Cases Cited
- Kumho Tire Co. v. Carmichael, 526 U.S. 137 (U.S. 1999) (district courts have broad discretion in determining admissibility of expert testimony)
- Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (U.S. 1993) (expert evidence must be reliable and relevant)
- United States v. Valencia, 600 F.3d 389 (5th Cir. 2010) (reliability and relevance are the key gates for expert evidence)
- Mathis v. Exxon Corp., 302 F.3d 448 (5th Cir. 2002) (credibility of experts and correctness of underlying facts are for the jury, not for exclusion of testimony)
- Micro Chem., Inc. v. Lextron, Inc., 317 F.3d 1387 (Fed. Cir. 2003) (appellate review of district court discretion in admitting expert testimony)
- Pipitone v. Biomatrix, Inc., 288 F.3d 239 (5th Cir. 2002) (trial court is a gatekeeper, not a trier of fact on expert evidence)
- Tramonte v. Fibreboard Corp., 947 F.2d 762 (5th Cir. 1991) (scope of rebuttal testimony left to trial judge’s discretion)