How to Use a Noninferiority Trial: Users' Guides to the Medical Literature

Clinical investigators are increasingly testing treatments that have the primary benefit of decreased burden or harms relative to an existing standard. The goal of the resulting randomized trials--called noninferiority trials--is to establish that the novel treatment's effectiveness is not substantially less than the existing standard. Conclusions from these trials are, however, based on noninferiority thresholds specified by authors whose …