Common design concepts in randomized controlled trials

Abstract

It is a known fact that Randomized Controlled Trials (RCTs) are the gold standard design methods in medical investigations particularly when the aim is comparison of medical therapies or effectiveness of intervention between treatment groups. This design method, once carefully followed, presents the highest level of evidence attainable in the measurement of treatment effect. Oftentimes, researchers confuse concepts related to the design of RCTs and thereby jeopardizing its benefits. Furthermore, in resource‑poor settings, a very limited access to educational materials on design, conduct, and reporting of clinical trials exists. This among other reasons explains why most studies in such settings are observational in nature as RCTs are not as popular. This review adopted a narrative synthesis approach to aggregate current knowledge scattered in literatures in respect of selected common design concepts in RCTs so as to elucidate on their meaning and demands. Overall, 25 literatures drawn majorly from the PubMed database including 8 textbook materials were involved in examining the following concepts; Study Population in RCTs Setting, Primary and Secondary Outcome Measures, Single and Multicenter Trials, Pragmatic and Explanatory trials, and Blinding. Appropriate search terms for each of the concepts were entered into the PubMed database and relevant articles accessed. This review article, intended for educational purposes could also serve as a guide, especially for new entrants, in the design of RCTs. It is hoped that this educational material would contribute immensely toward maximizing the benefits of this all‑important design method.