Randomized clinical trial: gold standard of experimental designs - importance, advantages, disadvantages and prejudices

Abstract

BACKGROUND: Randomized controlled trial (RCT) is the gold standard of experimental design or clinical trial design. Only by RCT in research, the cause-and-effect relationship between a set of independent and dependent variables could be demonstrated. RCT has added advantages over other experimental designs due to the presence of the control group. The importance of control in health research trials and its advantages to be elaborated. Though various threats to internal validity in health research trials could be minimized by RCT, various biases in RCT and disadvantages add to its discredit. OBJECTIVE: The aim of the present narrative review is to brief the characteristics, advantages, disadvantages, and various biases in RCT. METHODS: This review does not follow the PRISMA statement, as it was a narrative review. Two databases, namely, Medline through PubMed and Scopus, were searched from inception to July 2020 for the information pertaining to RCTs and included in this narrative review. Only English language articles were searched with the keywords, “Randomized controlled trial,” “Randomized clinical trial,” “experimental design,” and “experimental study.” These keywords are linked together by the Boolean words, “AND,” “OR” and “NOT.” Conference proceedings and only abstracts were not considered for the review. RESULTS: RCTs were explained under characteristics, advantages, disadvantages, importance, and advantages of controls in research, the principle of equipoise, RCTs in the pediatric population, RCTs in the geriatric population, threats to internal validity and steps to minimize them and various biases in RCTs. CONCLUSION: The narrative presentation of RCTs under various important topics have been explained in this review.