Randomized controlled trials: Design, measures, and classic examples

The randomized controlled trial is considered the “gold standard” among study designs due to its potential to eliminate selection bias and provide an estimate of the effect size between the factual and the counterfactual. Several key components must be carefully considered to construct a valid trial to answer the research question of interest. These include specifics about the study question, interventions, controls, outcomes, randomization, blinding, and statistics. Three examples of randomized controlled trials are described to illustrate how considerations may differ based on the objectives of the study. Each research question requires an individualized approach factoring in available resources and feasibility.