Table 4.
Main Effects of Daily Stress, Shift Worker Status, and Daily Work Schedule on Self-Report and Actigraphy Total Sleep Time
| Self-Report Total Sleep Time (min.) | Actigraphy Total Sleep Time (min.) | |||||
|---|---|---|---|---|---|---|
| Predictors | Estimates | CI | p | Estimates | CI | p |
| (Intercept) | 479.257 | 456.880 – 501.635 | <0.001 | 416.906 | 392.591 – 441.221 | <0.001 |
| Daily stress | −6.104 | −9.745 – −2.463 | 0.001 | −0.776 | −4.345 – 2.793 | 0.670 |
| Age | −1.185 | −1.588 – −0.782 | <0.001 | −0.618 | −1.055 – −0.180 | 0.006 |
| Gender | 14.385 | −1.829 – 30.598 | 0.082 | 22.437 | 4.811 – 40.062 | 0.013 |
| Shift worker status | 9.412 | −1.819 – 20.644 | 0.100 | 7.520 | −4.416 – 19.456 | 0.217 |
| Daily work schedule (day shift) | 3.024 | −3.709 – 9.758 | 0.379 | −3.560 | −10.006 – 2.887 | 0.279 |
| Daily work schedule (night shift) | −113.151 | −125.091 – −101.210 | <0.001 | −101.524 | −113.229 – −89.819 | <0.001 |
| Random Effects | ||||||
| σ2 | 9905.91 | 8276.16 | ||||
| τ00 | 1107.78 ID | 1513.31 ID | ||||
| ICC | 0.10 | 0.15 | ||||
| N | 389 ID | 387 ID | ||||
| Observations | 4759 | 4428 | ||||
| Marginal R2 / Conditional R2 | 0.107 / NA | 0.090 / NA | ||||
Note. Bold values represent p <.05 estimates. Gender was coded as 0 = male, 1 = female. Shift worker status was coded as 0 = day worker (worked no night shifts in the past 14 days), 1= night shift worker (worked at least one night shift in the past 14 days). Daily work schedule was dummy coded, with days off as the reference group. Daily stress and daily work schedule are within-person (level 1) variables and all other predictors are between-person (level 2) variables. CI = 95% confidence intervals. p = p-value. For random effects: σ2 represents level 1 variance (within-person), τ00 represents level 2 variance (between-person), ICC represents the intraclass correlation coefficient, N is the total Level 2 sample size, and Observations are the number of Level 1 daily observations.