Anything You Can Do I Can Do Better

Newly introduced drugs or treatments may not be substantively more effective than current therapies, but these drugs or treatments may have distinct advantages in terms of lower costs or fewer or less severe side effects. Demonstrating the utility of a novel treatment is thus unlike usual hypothesis testing, in which researchers seek to prove that treatments differ (i.e., that one treatment is better than another). Instead, researchers must prove that the treatments are equivalent in effectiveness (i.e., that the treatments do not differ). I discuss here how to execute this type of study: the non-inferiority study.