Comparing Drug Effectiveness at Health Plans: The Ethics of Cluster Randomized Trials‪.‬

"Cluster randomized trials," in which groups of patients are randomly assigned to different therapeutic interventions, provide a powerful way of evaluating drugs. CRTs have not been widely used, in good part because of concerns about whether patients must give informed consent to participate in them. A better understanding of how CRTs fit into clinical practice resolves the concerns. In spite of the thousands of articles published every year in medical journals, many questions remain about the best pharmaceutical treatments for common chronic conditions. In the absence of solid evidence about effectiveness, patients and clinicians base treatment decisions on an assortment of other factors--conventional wisdom, personal experience, advertisements, and cost. Partly for this reason, treatment regimens vary substantially from clinician to clinician, practice to practice, and region to region.