Evidence-based Urology: Subgroup Analysis in Randomized Controlled Trials

In randomized controlled trials, investigators often explore the possibility that the treatment effects differ between subgroups (eg, women vs men, old vs young, more versus less severe disease). Investigators often inappropriately claim subgroup effects (also called "effect modification" or "interaction") when the likelihood of a true effect modification is low. Criteria for assessing the credibility of subgroup analyses, nicely summarized in …