![]() Sample size calculations and analysis must make allowance for both the clustered nature of the design and the confounding effect of time. A result that initially might seem suggestive of an effect of the intervention may therefore transpire to be the result of a positive underlying temporal trend. This implies that the effect of the intervention might be confounded with any underlying temporal trend. In a stepped wedge design more clusters are exposed to the intervention towards the end of the study than in its early stages. As in all cluster trials, stepped wedge trials with individual recruitment and without concealment of allocation (or blinding of the intervention) are at risk of selection biases. While not exclusively for the evaluation of service delivery interventions, it is particularly suited to evaluations that do not rely on individual patient recruitment. ![]() It is a pragmatic study design which can reconcile the need for robust evaluations with political or logistical constraints. The design involves random and sequential crossover of clusters from control to intervention until all clusters are exposed. The stepped wedge cluster randomised trial is a novel research study design that is increasingly being used in the evaluation of service delivery type interventions.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |