“Hallucinations” by West and Lexis AI? A Cautionary Study and Cautions About the Study, Michael Berman – “This post is a follow up to “Hallucinations” by West’s CoCounsel? (Apr. 7, 2026). In U.S. v. Farris, __ F. 4^th __, 2026 WL 915082, at *1 (6^th Cir. Apr. 3, 2026) (per curiam), the court found errors in a brief prepared using Westlaw’s CoCounsel.  It appears that the tool was used after August 2025. Id. at *2. A 2024 academic study found hallucinations by major AI products in the legal market. The study should be read with caution in 2026.  While it recognizes value in the AI products, it reports flaws in what appear to me to be older versions of the products. After a preprint version was posted, it was “subsequently peer-reviewed and published in the Journal of Empirical Legal Studies in 2025….”  Westlaw AI and Lexis+ AI Still Hallucinate: What the Stanford Study Actually Found – LegalAIWorld (undated); see Varun Magesh, Faiz Surani, Matthew Dahl, Mirac Suzgun, Christopher D. Manning, Daniel E. Ho, Hallucination‐Free? Assessing the Reliability of Leading AI Legal Research Tools – Magesh – 2025 – Journal of Empirical Legal Studies – Wiley Online Library (published Apr. 23, 2025). The scholarly article concludes by emphasizing both the value of, and the need to verify, A.I. output.  Verification, of course, is not only good advice, but also an ethical mandate.  It is worth reviewing the study…”