Expert Witness Blog

Expert insights, legal technology trends, and best practices for working with expert witnesses

A Whistleblower's Own Expert Used ChatGPT - the Case Ended Before Any Judge Ruled on It

United States of America and State of Nevada ex rel. Michael D. Khoury, M.D. v. Mountain West Anesthesia, LLC, et al. — U.S. District Court, District of Utah, Central Division, Case No. 2:20-cv-00372-TC-CMR - Case dismissed September 30, 2025 — Hon. Tena Campbell, United States District Judge; Hon. Cecilia M. Romero, United States Magistrate Judge - A whistleblower's own testifying expert admitted at deposition that ChatGPT helped produce his report's fabricated testimony - then the case ended before a judge ever ruled on the fallout.

Expert Witness Testimony

Anthropic’s Own Expert Loses a Paragraph to an AI-Fabricated Citation

Concord Music Group, Inc., et al. v. Anthropic PBC - U.S. District Court, Northern District of California, Case No. 24-cv-03811-EKL (SVK) Decided and filed May 23, 2025 - Hon. Susan van Keulen, United States Magistrate Judge - In a discovery order in the Anthropic music-lyrics copyright case, a judge struck one paragraph of the company’s own expert’s declaration after finding Claude.ai had invented a citation’s title and author list.

Expert Witness Testimony

AI Misinformation Expert Excluded Over Fake, AI-Generated Citations

Christopher Kohls and Mary Franson v. Keith Ellison, Attorney General of Minnesota, and Chad Larson, County Attorney of Douglas County — U.S. District Court, District of Minnesota, Case No. 24-cv-3754 (LMP/DLM) Decided January 10, 2025 - Hon. Laura M. Provinzino, United States District Judge - A Stanford expert on AI misinformation used GPT-4o to help draft his declaration - and the tool’s fake citations got his own testimony excluded from a federal case about the dangers of AI.

Expert Witness Testimony

Surrogate’s Court Rejects AI-Checked Damages, Sets Disclosure Rule for Expert Evidence

In the Matter of the Accounting by Susan F. Weber, as Trustee of the Michael S. Weber Trust — Surrogate’s Court, Saratoga County, New York, File No. 1845-4/B, 85 Misc. 3d 727 Decided October 10, 2024 - Hon. Jonathan G. Schopf, Saratoga County SurrogateAn expert’s Microsoft Copilot-checked damages figure came back different every time the court ran the same query itself - prompting a New York court to require disclosure, and a reliability hearing, before AI-generated evidence can be used at trial.

Expert Witness Testimony

Bard MDL Court Rejects Untimely AI-Hallucination Attack on Expert

In re: Bard Implanted Port Catheter Products Liability Litigation - No. 2:23-md-03081, U.S. District Court, District of Arizona (Phoenix Division) — Senior Judge David G. Campbell — Order dated August 12, 2026 Filed Aug. 8, 2023 | Case Flags: ATTYADD, LEAD, MULTI-DISTRICT, STD | Nature of Suit: 365 Product Liability | Cause: 28:1332 Diversity-Product Liability | Jury Demand: Both - Defendants accused a materials science expert of hiding his ChatGPT use and pointed to hallucinated citations in an unrelated case - but the court found the argument came too late, and too thin, to keep his opinions out.

AI Cases

Court Orders Expert to Turn Over the AI Prompts Behind Her Report

Conservation Law Foundation, Inc. v. Equilon Enterprises LLC d/b/a Shell Oil Products US, Inc. et al., No. 3:21-cv-00933-VDO (D. Conn.) - Judge Thomas O. Farrish, order entered May 18, 2026 (granting ECF No. 941) - A federal court in Connecticut ordered an expert witness to turn over the AI prompts behind her report, ruling that generative-AI methodology is discoverable like any other expert reliance material.

Expert Witness Playbook

Experts excluded for AI hallucinated citations in expert reports: LeDoux v. Outliers, Inc., et al.

3:24-cv-05808-TMC (W.D. Wash., Tacoma) - Order Granting Defendants' Motion for Summary Judgment, Dkt. 269, filed Aug. 18, 2026, and Order Granting Defendants' Motion for Partial Summary Judgment, Dkt. 202, filed Jan. 9, 2026 - before U.S. District Judge Tiffany M. Cartwright - Plaintiff’s counsel fed the same AI-generated citation table to two experts. Neither checked it - and when the fabrications surfaced, one expert’s entire report went down with them.

Expert Witness Playbook

Could Cost-Recovery Clauses Fix the Late-Instruction Problem?

Category: Timing and Instruction of Expert Witnesses - If cost sensitivity drives much of the late-instruction problem, would making pre-dispute expert costs reliably recoverable actually fix it? This piece tests the idea honestly, finding real but partial value, and lays out what counsel can do now, regardless of the applicable cost regime, to strengthen a future recoverability argument.

Expert Witness Playbook

Who's Really to Blame When Expert Instruction Comes Late?

Category: Timing and Instruction of Expert Witnesses - When an expert is instructed too late, counsel blames a hesitant client and clients blame a lawyer who never made the case clearly. Both accounts are usually partly right. This piece examines how clients, counsel, and structural industry factors each genuinely contribute to delay, and why moving past blame toward a documented early checkpoint works better than assigning fault after the fact.

Expert Witness Playbook

The Three Real Reasons Experts Get Brought In Too Late

Category: Timing and Instruction of Expert Witnesses - Late expert instruction traces back to one of three distinct root causes, cost sensitivity, role misunderstanding, or genuine legal-team strategy, each with its own psychology and its own specific fix. This piece breaks down all three, shows how they compound and disguise each other, and offers a diagnostic for identifying which one is actually driving delay in a given case.