Table 4 Power for comparison of HIV incidence between Arms A and B, with 7 communities per arm and Population Cohort of 2,500 adults per community (assuming that on average 2,125 (85%) will be HIV-uninfected at baseline and that loss to follow-up will be 20% after 2 years and 25% after 3 years)
HIV incidence rate/100 py (control arm) | Between-cluster coefficient of variation (k) | Effectiveness (%) Arm A | Effectiveness (%) Arm B | Power (%) |
|---|---|---|---|---|
1.0 | 0.15 | 50% | 20% | 89% |
1.0 | 0.15 | 50% | 25% | 78% |
1.0 | 0.15 | 55% | 25% | 92% |
1.0 | 0.15 | 55% | 30% | 82% |
1.0 | 0.15 | 60% | 25% | 98% |
1.0 | 0.15 | 60% | 30% | 94% |
1.0 | 0.15 | 65% | 25% | 99% |
1.0 | 0.15 | 65% | 30% | 99% |
1.0 | 0.20 | 50% | 20% | 78% |
1.0 | 0.20 | 50% | 25% | 65% |
1.0 | 0.20 | 55% | 25% | 83% |
1.0 | 0.20 | 55% | 30% | 71% |
1.0 | 0.20 | 60% | 25% | 93% |
1.0 | 0.20 | 60% | 30% | 87% |
1.0 | 0.20 | 65% | 25% | 98% |
1.0 | 0.20 | 65% | 30% | 96% |
1.5 | 0.15 | 50% | 20% | 94% |
1.5 | 0.15 | 50% | 25% | 86% |
1.5 | 0.15 | 55% | 25% | 96% |
1.5 | 0.15 | 55% | 30% | 90% |
1.5 | 0.15 | 60% | 25% | 99% |
1.5 | 0.15 | 60% | 30% | 98% |
1.0 | 0.20 | 65% | 25% | 99% |
1.0 | 0.20 | 65% | 30% | 99% |
1.5 | 0.20 | 50% | 20% | 84% |
1.5 | 0.20 | 50% | 25% | 72% |
1.5 | 0.20 | 55% | 25% | 88% |
1.5 | 0.20 | 55% | 30% | 78% |
1.5 | 0.20 | 60% | 25% | 96% |
1.5 | 0.20 | 60% | 30% | 92% |
1.0 | 0.20 | 65% | 25% | 99% |
1.0 | 0.20 | 65% | 30% | 98% |