Sample size determinations for stepped-wedge clinical trials from a three-level data hierarchy perspective.

ABSTRACT: Stepped-wedge (SW) designs have been steadily implemented in a variety of trials. A SW design typically assumes a three-level hierarchical data structure where participants are nested within times or periods which are in turn nested within clusters. Therefore, statistical models for analysis of SW trial data need to consider two correlations, the first and second level correlations. Existing power functions and sample size determination formulas had been derived based on statistical models for two-level data structures. Consequently, the second-level correlation has not been incorporated in conventional power analyses. In this paper, we derived a closed-form explicit power function based on a statistical model for three-level continuous outcome data. The power function is based on a pooled

SUBMITTER: Heo M 

PROVIDER: S-EPMC5026912 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature