The design of randomized controlled trials.

ABSTRACT

Today's clinical practice relies on the application of well-designed clinical research, the gold standard test of an intervention being the randomized controlled trial. Principles of the randomized controlled trial include emphasis on the principal research question, randomization, and blinding; definitions of outcome measures, inclusion and exclusion criteria, and comorbid and confounding factors; enrolling an adequate sample size; planning data management and analysis; preventing challenges to trial integrity, such as dropout, drop-in, and bias. The application of pretrial planning is stressed to ensure the proper application of epidemiological principles, resulting in clinical studies that are feasible and generalizable. In addition, funding strategies and trial team composition are discussed.