Why do so many medical practices that begin with such promise and confidence turn out to be either ineffective at best or harmful at worst? Adam Cifu of the University of Chicago's School of Medicine and co-author (with Vinayak Prasad) of Ending Medical Reversal explores this question with EconTalk host Russ Roberts. Cifu shows that medical reversal--the discovery that prescribed medical practices are ineffective or harmful--is distressingly common. He contrasts the different types of evidence that support or discourage various medical practices and discusses the cultural challenges doctors face in turning away from techniques they have used for many years.