Clustering & treatment effect heterogeneity in stepped wedge cluster trials
Modelling differential clustering and treatment effect heterogeneity in parallel and stepped wedge cluster trials
Abstract: Cluster randomized trials are frequently used in health service evaluation. It is common practice to use an analysis model with a random effect to combine between cluster information about treatment effects. It is increasingly being acknowledged that intervention effects might vary across clusters, or the variation between clusters differs across the randomized arms. It has been proposed in both parallel cluster trials and stepped wedge designs that this heterogeneity can be allowed for by incorporating additional random effect(s) into the model. Here we show that the choice of model parameterization needs careful consideration as some parameterization for additional heterogeneity induce unnecessary assumptions. We suggest more appropriate parameterizations, discuss their relative advantages and demonstrate the implications of these model choices using practical examples of a parallel cluster trial and a simulated stepped wedge trial.
Speaker: Dr Karla Hemming, Institute of Applied Health Research, University of Birmingham
Visitors will be met at reception 10 minutes before the start of the seminar.
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