Ban bets on unfinished clinical trials.

Abstract

In July, the prediction market platform Kalshi and data company AppliedXL began a pilot market listing binary, yes-or-no contracts on whether named late-stage clinical trials meet their preregistered primary end points. Kalshi lists contracts only after trial enrollment closes, reasoning that a visible price-in effect the market's odds that the trial succeeds-could sway recruitment. But closing enrollment does not end an experiment. Traders can buy and sell contracts while trial participants still attend visits, staff still measure outcomes, and interim results remain confidential. The line belongs at the end of the experiment, not of enrollment: No public contract on a trial's efficacy or safety result should trade while the trial is ongoing and before the result is public.