Which Randomization Methods Are Used Most Frequently in Clinical Trials? Results of a Survey by the Randomization Working Group

In June–July 2022, the Randomization Working Group (https://randomization-working-group.rwth-aachen.de) conducted an online survey on the current practices in the application of randomization in clinical trials. Of 145 unique respondents, 137 (94.5%) identified themselves as statisticians. The majority of respondents were from academia and pharmaceutical companies. Permuted block randomization, with or without stratification, was the most frequently chosen method of randomization for RCTs. Interactive Web-Based Response Systems (IWRS) and “in-house” or a combination of “in-house and outsourced” randomization models were found to be most common in practice. Over 80% of respondents perceived some challenges to adoption of new randomization methods that may have more desirable properties. Over 80% of respondents identified opportunities for improving current practice, including education/training, development of standards/guidance on randomization, and adoption of validated software for generating randomization sequences. In summary, practitioners acknowledge the pivotal role of randomization in clinical trials. There are some perceived challenges to successful implementation of randomization, and there are opportunities for improving practice.