Paid medical malpractice claims: How strongly does the past predict the future?

When does the past predict the future? In financial markets, warnings that "past results are no guarantee of future performance" are ubiquitous. But in multiple fields (including professional sports, insurance, and criminal law), it is widely believed that the past is a useful guide to the future. Does that insight apply to medical malpractice ("med mal")? Using a novel dataset (which includes detailed data on all licensed physicians and all paid claims in Illinois over a 25-year period), we study whether past paid med mal claims, physician characteristics, and specialty predict future paid med mal claims. After controlling for other factors, physicians with a single prior paid claim have a fourfold higher risk of future claims than physicians with zero prior paid claims. The more prior paid claims a physician has, the higher the likelihood of a future paid claim. Multiple factors (male gender, having an MD, attending a non-U.S. medical school, practicing in a high-claim-risk specialty, and mid-career status [6-15 prior years of experience]) predict a higher likelihood of having one or more paid med mal claims.