Physicians, acting in their role as experts, are often faced with situations where they must trade off personal and patient welfare. Physicians’ incentives vary based on the organizational environment in which they practice. We use the publication of a major clinical trial, which found that a common knee operation does not improve outcomes for patients with osteoarthritis, as an “informational shock” to gauge the impact of physicians’ agency relationships on treatment decisions. Using a 100% sample of procedures in Florida from 1998 to 2010, we find that publication of the trial reduced procedure volume, but the magnitude of the decline was smaller in physician‐owned surgery centers. Incentives affected physicians’ reactions to evidence.