Table 1.
Simulated scenarios for sample size determination in the design of a hypothetical study
| Standard Scenario | Relaxed significance level | Relaxed Power | Baseline Mortality shifted away from 50% | Inflated delta | |
|---|---|---|---|---|---|
| Significance level (two-sided) | 0.05 | 0.1 | 0.05 | 0.05 | 0.05 |
| Power | 90% | 90% | 80% | 90% | 90% |
| Baseline (placebo) mortality rate | 50% | 50% | 50% | 40% | 50% |
| Delta (ARR) | 10% | 10% | 10% | 10% | 15% |
| Required sample size | 1076 | 884 | 816 | 992 | 480 |
Inflation of delta has a substantially larger impact on required sample size than changes in the other variables. ARR, absolute risk reduction.