Fundamentals of Randomization in Clinical Trial

Fatemeh Baghbaninaghadehi, Susan Armijo-Olivo, Linda Woodhouse


The randomized control trial (RCTs) is widely accepted to be the best design for evaluating the efficacy of new therapies, and thus it is accepted as the gold standard to evaluate treatment effects. Random assignment of patients to the treatment ensures the internal validity of the comparison of new treatment with a control group. Unfortunately, the randomization process in most research studies is not implemented properly. The purpose of this review is to provide researchers and scholarly clinicians with a better understanding of different options to achieve proper randomization. The information presented in this article will also help to better design and interpret the results of clinical trials. Therefore, a brief definition of randomization plus its concise benefits in clinical trials, and the processes of an accurate randomization procedure, generation of unpredictable random allocation sequence and allocation concealment are considered. Recommendations are made to select the suitable techniques of generation of random allocation and allocation concealment. Finally, the authors describe how the appropriate implementation of these two procedures reduces the potential for biases throughout the study and improves the power of the study.



Allocation Concealment; Study Power; Randomized Control Trial; Random Allocation

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