Randomized Trials

Abstract

Randomized trials are interventional studies that administer specific treatments or control procedures to study participants. The primary advantage of the randomized design is the ability to separate the causal impact of treatments from the characteristics of people who receive these treatments. Characteristics that impact the internal validty of randomized studies include the randomization procedure, choice of conparator, blinding, concealment, adherence, accuracy of the study measurements, and the analytic plan. The results of randomized trials may have limited external validity due to preferential inclusion of relatively healthy participants and careful monitoring procedures.