Table 4.
Power calculations: SHARE trials
| Assumptions | Pakistan | India |
|---|---|---|
| Unit of randomisation | Villages (stratified within union councils) | Individual (stratified by urban/rural area of residence) |
| Intra-cluster correlation | 0.07 in the intervention arm | 0.05 in the intervention arm (30 therapists; within-therapist clustering) [22, 32, 33] |
| 0.05 in the control arm (between-village clustering) [22] | ||
| Loss to follow-up over 6 months | 20 % [22] | 15 % [8] |
| Allocation ratio (intervention/control) | 1:1 | 1:1 |
| Number of participants | 560 (14 per village; 40 village clusters) | 280 |
| Outcome | Power | |
| Remission at 6 months (PHQ-9 < 10) of 65 % in the intervention arm vs 45 % in the control arm [22] | 90 % | 86 % |
| Remission at 6 months (PHQ-9 ≤ 5) of 38 % in the intervention arm vs 22 % in the control arm [22] | 81 % | 74 % |
| Depression severity at 6 months (PHQ-9 score) – effect size 0.4 | 90 % | 84 % |