You are doing a cluster randomised controlled trial. However, your sample size is incorrect: you have not adjusted for clustering. Also your analysis strategy is incorrect: again you need to adjust for clustering. Even if you did the adjustment you only have 4 clusters, which is insufficient cluster replication. You need to increase the number of clusters to at least 8 and recalculate your sample size.
Wrong power calculation and analysis
1 March 2012
You are doing a cluster randomised controlled trial. However, your sample size is incorrect: you have not adjusted for clustering. Also your analysis strategy is incorrect: again you need to adjust for clustering. Even if you did the adjustment you only have 4 clusters, which is insufficient cluster replication. You need to increase the number of clusters to at least 8 and recalculate your sample size.
Competing interests
None