Table 2.
Zero-inflated Poisson regression with number of sick days as the dependent variable
| Model 1 | Model 2 | Model 3 | Model 4 | |
|---|---|---|---|---|
| Count component | ||||
| Age | −0.016 | −0.017 | −0.049 | −0.031 |
| Age squared | 0.0002 | 0.0002 | 0.0007 | 0.0005 |
| Previous deliveries | 0.374 | 0.330 | ||
| Previous deliveries×age | −0.008 | −0.007 | ||
| II Lower professionals | 0.056 | |||
| IIIa Higher routine | 0.185 | |||
| IIIb Lower routine | 0.240 | |||
| V Technicians | 0.069 | |||
| VI Skilled | 0.212 | |||
| VIIa Semiskilled and unskilled | 0.285 | |||
| VIIb Agricultural | 0.200 | |||
| Missing | 0.107 | |||
| Constant | 4.448 | 3.350 | 3.749 | 3.231 |
| Excess zero component | ||||
| Constant | −1.341 | −1.341 | −1.341 | −1.341 |
| Observations | 216 541 | 216 541 | 216 541 | 216 541 |
| Cragg and Uhler's | 0.023 | 0.179 | 0.290 | 0.462 |
The coefficients in the count component are adjusted for Working hours, Leave, Year and Marital status in models 2–4. The coefficients of the excess zero component are adjusted for Working hours and Leave in all four models.