Table 1 Estimates of the Minimum Detectable Difference (MDD) for trial with 20 clusters per arm, to detect an increase in an event rate from 40%
From: Sample size calculations for cluster randomised controlled trials with a fixed number of clusters
Power = 80% | Power = 90% | |||
|---|---|---|---|---|
40% vs 50% | MDD | 40% vs 50% | MDD | |
ICC = 0.005 | n I = 385 | N/A | n I = 515 | N/A |
n C = 440 | n C = 600 | |||
m = 22 | m = 30 | |||
ICC = 0.07 | MDD = 12% | MDD = 14% | ||
n I = 267 | n I = 262 | |||
n C = 3,780 | n C = 2,920 | |||
m = 189 | m = 146 | |||