A New York judge recently called out an expert witness for using Microsoft's Copilot chatbot to cross-check a damages estimate in a real estate dispute—one that partly depended on an accurate assessment of damages to win.
In an order Thursday, judge Jonathan Schopf warned that, "due to the nature of the rapid evolution of artificial intelligence and its inherent reliability issues," any use of AI should be disclosed before testimony or evidence is admitted in court. Admitting that the court "has no objective understanding as to how Copilot works," Schopf suggested that the legal system could be disrupted if experts started using chatbots en masse.
His warning came after an expert witness, Charles Ranson, used Copilot to cross-check calculations in a dispute over a $485,000 rental property in the Bahamas that had been included in a trust for a deceased man's son. The court was being asked to assess if the executrix and trustee—the deceased man's sister—breached her fiduciary duties by delaying the sale of the property while admittedly using it for personal vacations.
To win, the surviving son had to prove that his aunt breached her duties by retaining the property, that her vacations there were a form of self-dealing, and that he suffered damages from her alleged misuse of the property.
It was up to Ranson to figure out how much would be owed to the son had the aunt sold the property in 2008 compared to the actual sale price in 2022. But Schopf found that that parts of Ranson's testimony were "entirely speculative" and failed to consider obvious facts, such as the pandemic's impact on rental prices or trust expenses like real estate taxes.
Therefore, the Court "found his testimony and opinion not credible" and specifically called Ranson out for using "Microsoft Copilot, a large language model generative artificial intelligence chatbot, in cross-checking his calculations."