Table 2.
Ratio of the average of estimated standard error to the standard deviation of the empirical distribution of treatment effects, and coverage probability of the 95% confidence interval for data simulated under the 3 conditions. ZI = zero inflation parameter.
| Unconditional/Unadjusted | Unconditional/Adjusted | Conditional/Unadjusted | Unconditional/Adjusted | |||||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| Ratio | % Coverage | Ratio | % Coverage | Ratio | % Coverage | Ratio | % Coverage | |
| Condition 1 | ||||||||
| Poisson | 0.853 | 0.864 | 0.976 | 0.917 | 1.105 | 0.676 | 1.105 | 0.864 |
| ZI | 0.948 | 0.858 | 0.963 | 0.936 | 0.979 | 0.858 | 0.971 | 0.930 |
| Condition 2 | ||||||||
| Poisson | 0.836 | – | 0.939 | – | 1.107 | – | 1.030 | – |
| ZI | 0.961 | 0.898 | 0.974 | 0.930 | 1.024 | 0.812 | 1.024 | 0.914 |
| Condition 3 | ||||||||
| Poisson | 0.891 | 0.994 | 0.976 | 0.990 | 1.089 | 0.968 | 1.037 | 0.978 |
| ZI | 0.986 | 0.840 | 1.000 | 0.848 | 1.060 | 0.542 | 1.053 | 0.784 |