Power to detect association between an independent variable with 50% prevalence and PrEP outcomes (N=528 evaluable)
| OR | P=0.5 | P=0.6 | P=0.7 | P=0.8 |
| 1.75 | 88.7 | 85.6 | 78.6 | 65.0 |
| 2.00 | 97.3 | 95.8 | 91.7 | 80.9 |
| 2.25 | 99.5 | 98.9 | 97 | 90.0 |
p=proportion with the outcome (eg, PrEP initiation) in the reference group.
PrEP, pre-exposure prophylaxis.