Barbara Osimani

1 Introduction Because in typical medical experiments it is not feasible to test all members of the target population, scientists rely on samples. This requires that the sample represents the target population at least to some degree. Surprisingly, despite its crucial role, representativeness remains a controversial topic within the methodology of medical science. It remains unclear not only how to best define and ensure representativeness, but also whether it is worth pursuing in the first place.

Abstract : Under exceptional circumstances, including high rates of protocol non-compliance, per-protocol (PP) analysis can better indicate the real-world benefits of a medical intervention than intention-to-treat (ITT) analysis. Exemplifying this, the first randomized clinical trial (RCT) considered found that colonoscopy screenings were marginally beneficial, based upon ITT analysis, with only 42% of the intervention group actually undergoing the procedure.