Cluster Randomized Controlled Trials: A Quick Update on Concepts and Types

Bolaji Emmanuel Egbewale*

Cluster Randomized Controlled Trials: A Quick Update on Concepts and Types. Cluster randomized controlled trials have certain complexities both at design and statistical analysis stages of the experiment. Although, this experimental study approach offers solutions in situations where it would be inappropriate to randomize individuals into treatment arms its design and statistical analysis are not without certain unique challenges.

Compared to individual randomized controlled trials, very limited understanding of the design concepts in cluster randomized controlled trials exists, this perhaps explain reasons it is not as popular as the former. This short note presents a quick description of cluster randomized controlled trials with a view to enhance capacity in its design, conduct and management.

It will also provide students and researchers with ready-made information necessary to make appropriate choices regarding type of cluster randomized trials given a prevailing research environment. Cluster randomized trials are experiments in which unit of randomization are not individuals as in conventional randomized controlled trials, groups of subjects, social units or clusters rather than individuals are randomly allocated to treatment groups.

Campbell et al, 20044 reported that, when compared with individually randomized trials, cluster randomized trials are more complex to design, require more participants to obtain equivalent statistical power, and require more complex analysis.

Clin Trial Pract Open J. 2017; 1(1): 15-17. doi: 10.17140/CTPOJ-1-103