Power calculations to detect an effect size=0.35 of 1 SD between the intervention and usual care periods, assuming an intracluster correlation of 0.1 and alpha of 5% for a two-sided test for a stepped wedge cluster randomised controlled trial with nine clusters and three steps
| Probability of remaining at the centre | Within-participant correlation | Sample cluster size | Power* |
|---|---|---|---|
| 0 | NA | 30 | 0.81 |
| 0.2 | 0.2 | 30 | 0.82 |
| 0.2 | 0.7 | 30 | 0.86 |
| 0.6 | 0.2 | 30 | 0.86 |
| 0.6 | 0.7 | 30 | 0.94 |
*Power calculations based on 2000 simulations.
NA, not available.