The role of Comparators in Clinical Trials
Drug development is a very complex, long and expensive process. Once a suitable molecule is identified then clinical trials are undertaken to establish the effect of an intervention.
Treatment effects are efficiently isolated by controlling for bias and confounding and by minimizing variation. Key features of clinical trials that are used to meet this objective are randomization (possibly with stratification), adherence to intent-to-treat (ITT) principles, blinding, prospective evaluation, and use of a control group. Compared to other types of study designs (e.g., case-control studies, cohort studies, case reports), randomized trials have high validity but are more difficult and expensive to conduct.