Table 4. Explanatory factors for winter losses in Austria in the winter season 2015/16.
| Variable | Levels | Estimate (SE) | Odds (95% CI) | Z value | P |
|---|---|---|---|---|---|
| Intercept | -3.84 (0.57) | 0.02 (0.01–0.07) | -6.69 | < 0.0001 | |
| Mite infestation level autumn | 0.15 (0.02) | 1.17 (1.11–1.22) | 6.19 | < 0.0001 | |
| Years of experience | -0.04 (0.01) | 0.96 (0.93–0.99) | -2.81 | 0.0037 | |
| Colony strength autumn reference level: strong |
Normal | 0.44 (0.32) | 1.55 (0.83–2.90) | 1.38 | 0.8653 |
| Weak | 1.3 (0.39) | 3.68 (1.70–7.97) | 3.30 | 0.0218 | |
| Queen age autumn reference level: 0 year |
1 year | 0.06 (0.37) | 1.06 (0.52–2.19) | 0.16 | 0.1695 |
| >1 year | 1.10 (0.48) | 3.02 (1.17–7.75) | 2.28 | 0.0009 |
GLMM with binomial distribution, random factor ‘apiary’. The random factor improved the model significantly (Chi2 = 71.82, df = 1, P < 0.001). n = 1382 colonies; N = 188 apiaries, SE = standard error.