Hybrid sample size calculations for cluster randomised trials using assurance.

ABSTRACT:

Background/aims

Sample size determination for cluster randomised trials is challenging because it requires robust estimation of the intra-cluster correlation coefficient. Typically, the sample size is chosen to provide a certain level of power to reject the null hypothesis in a two-sample hypothesis test. This relies on the minimal clinically important difference and estimates for the overall standard deviation, the intra-cluster correlation coefficient and, if cluster sizes are assumed to be unequal, the coefficient of variation of the cluster size. Varying any of these parameters can have a strong effect on the required sample size. In particular, it is very sensitive to small differences in the intra-cluster correlation coefficient. A relevant intra-cluster correlation coefficie

SUBMITTER: Williamson SF 

PROVIDER: S-EPMC12476461 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature