Expert Witness Blog

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

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.