The optimal design of stepped wedge trials with equal allocation to sequences and a comparison to other trial designs.

ABSTRACT: Background/Aims We sought to optimise the design of stepped wedge trials with an equal allocation of clusters to sequences and explored sample size comparisons with alternative trial designs. Methods We developed a new expression for the design effect for a stepped wedge trial, assuming that observations are equally correlated within clusters and an equal number of observations in each period between sequences switching to the intervention. We minimised the design effect with respect to (1) the fraction of observations before the first and after the final sequence switches (the periods with all clusters in the control or intervention condition, respectively) and (2) the number of sequences. We compared the design effect of this optimised stepped wedge trial to the design effects of a paral

SUBMITTER: Thompson JA 

PROVIDER: S-EPMC5718336 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature