Expert insights, legal technology trends, and best practices for working with expert witnesses
State Court of Gwinnett County, Georgia · Civil Action File No. 24-C-05776-S6 · Order on Motion to Exclude Expert Opinion Testimony · Hon. Veronica Cope · Dated July 2, 2026 (e-filed July 8, 2026)
In re: Valsartan, Losartan, and Irbesartan Products Liability Litigation D.N.J., Camden Vicinage · MDL No. 2875 · No. 1:20-cv-00946-RBK-JS · Dkt. No. 3167 · Special Master Order (Hon. Thomas I. Vanaskie, Ret.) · September 3, 2025 - A special master let a pharmaceutical MDL expert’s opinions stand after his report cited nonexistent, AI-generated sources, ruling the lapse went to costs and cross-examination rather than admissibility.
In re: Social Media Adolescent Addiction Litigation N.D. Cal. · No. 4:22-md-03047-YGR (MDL No. 3047) · Dkt. No. 2750 · Hon. Yvonne Gonzalez Rogers · February 17, 2026 - A federal judge refused to strike a school-district expert’s opinions after some of his citations turned out to be AI-generated miscites, ruling the issue belonged on cross-examination — even as she flagged other parts of his report that would be excluded outright at trial.
Riddle Aggregates, LLC, Ornstein-Schuler, LLC, Tax Matters Partner v. Commissioner of Internal Revenue — U.S. Tax Court, Docket No. 31104-21, Judge Kathleen Kerrigan, trial testimony of March 18, 2026 - A Tax Court appraiser’s rebuttal reports, drafted with Grammarly, ChatGPT, and Gemini, cited a Yellow Book section and quotations that don’t exist - and were withdrawn once the judge said she had “grave concerns.”
Joseph Ferlito v. Harbor Freight Tools USA, Inc. - U.S. District Court, Eastern District of New York, Civil Action No. 20-cv-5615 (GRB)(SIL) Decided and filed April 23, 2025 - Hon. Gary R. Brown, United States District Judge - A products-liability expert ran his finished opinion past ChatGPT to see if it agreed - the court found that kind of AI use, after the fact and unrelied-upon, didn't threaten his testimony's reliability.
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.
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.
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.
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.
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.
