Table 2.
Mean of vaccination effect coefficient (standard error) and empirical power from 1000 simulations with true β1=0.693 when individual-specific have a normal distribution.
| Simulation parameters | Average number of cases | Mean of vaccination effect coefficient (standard error) | Empirical power (%) | |||
|---|---|---|---|---|---|---|
| α | σ | CPa/FEb | GEEc | CP/FE | GEE | |
| −5 | 1 | 510 | 0.682 (0.159) | 0.687 (0.159) | 96 | 97 |
| 1.5 | 936 | 0.664 (0.127) | 0.662 (0.132) | 100 | 100 | |
| −6 | 1 | 188 | 0.668 (0.279) | 0.668 (0.280) | 68 | 68 |
| 1.5 | 351 | 0.665 (0.207) | 0.661 (0.209) | 87 | 87 | |
| −7 | 1 | 69 | 0.600 (0.516) | 0.599 (0.516) | 35 | 35 |
| 1.5 | 130 | 0.661 (0.355) | 0.655 (0.356) | 55 | 54 | |
| −8 | 1 | 26 | 0.719 (0.624) | 0.718 (0.624) | 17 | 17 |
| 1.5 | 48 | 0.618 (0.574) | 0.611 (0.578) | 26 | 26 | |
a
CP, conditional Poisson model.
b
FE, fixed effects model.
c
GEE, generalized estimation equations.