A primer on randomized controlled trials

Abstract

Randomized Clinical Trials are held as the gold standard for quantifying the effect of an intervention across two or more groups. In such a trial an intervention is randomly allocated to one of two groups. The benefit of such a trial lies in its ability to establish nearly comparable groups of subjects in all manner except for the effect of the intervention. As such, the effect of a given intervention may be attributed solely to the intervention and not to any other extraneous factor. In the following editorial, we will discuss several issues that are important for understanding how to conduct and interpret randomized trials: choosing the study population, choosing the comparison group, choosing your outcome, study design, data analysis, and issues of inference. This editorial is intended to make the reader an educated consumer of such trial designs.

Donald S. Likosky, PhD

Figure 1.

Design of a randomized trial. Acknowledgment: H. Gilbert Welch, MD, MPH.