Random allocation to intervention groups remains the best method of ensuring that the groups being compared are similar at the onset of study and of avoiding removing selection bias between groups of patients. The success of randomization depends on two interrelated processes. First, an unpredictable allocation sequence must be generated based on a random procedure. Second, strict implementation of that sequence must be secured through an assignment mechanism called allocation concealment to prevent those involved in a trial from knowing upcoming assignments. Inadequate allocation concealment can lead to clinicians scheduling patient’s assignment and compromising the unpredictable allocation sequence.
Randomization was the basis for the design and conduct of clinical trials. However, the traditional randomized controlled trials (RCTs) were often randomized in a fixed manner with unbalanced potential covariates, which spured researchers to develop a more flexible and practical randomization method. Thus, the adaptive randomization emerged as the time needed. In this paper, the application of adaptive randomization in clinical trials was introduced, and its key points of implementation, advantages and disadvantages were summarized. The development space of the adaptive randomization in clinical applications was also discussed, and it provided evidence for the development of the drug clinical trials in China.