TABLE 2.
Results of the sleep timing trimmed mean ANOVA and follow‐up trimmed t tests
| Statistic | p | Difference, min (95% CI) | |
|---|---|---|---|
| Sleep duration | |||
| Trimmed ANOVA | |||
| Main effect of pandemic | Q = 0.02 | 0.887 | |
| Main effect of day | Q = 172.09 | <0.001 | |
| Interaction | Q = 63.31 | <0.001 | |
| Follow‐up trimmed t tests | |||
| Pre‐pandemic: free day – workday | t(343.0) = 14.44 | <0.001 | 39.24 (33.90, 44.58) |
| First wave: free day – workday | t(343.0) = 7.46 | <0.001 | 17.81 (13.11, 22.50) |
| Workday: first wave – pre‐pandemic | t(343.0) = 4.07 | <0.001 | 10.44 (5.39, 15.48) |
| Free day: first wave – pre‐pandemic | t(343.0) = −4.96 | <0.001 | −11.00 (−15.37, −6.63) |
| Average week sleep time (weighted average of free‐ and workdays) | |||
| First wave – pre‐pandemic | t(343.0) = 2.29 | 0.023 | 4.85 (0.68, 9.03) |
| Sleep‐onset | |||
| Trimmed ANOVA | |||
| Main effect of pandemic | Q = 98.05 | <0.001 | |
| Main effect of day | Q = 316.85 | <0.001 | |
| Interaction | Q = 28.73 | <0.001 | |
| Follow‐up trimmed t tests | |||
| Pre‐pandemic: free day – workday | t(354.0) = 17.01 | <0.001 | 39.97 (35.35, 44.60) |
| First wave: free day – workday | t(354.0) = 13.68 | <0.001 | 28.15 (24.10, 32.19) |
| Workday: first wave – pre‐pandemic | t(354.0) = 11.67 | <0.001 | 26.72 (22.22, 31.23) |
| Free day: first wave – pre‐pandemic | t(354.0) = 6.07 | <0.001 | 14.90 (10.07, 19.72) |
| Sleep‐end | |||
| Trimmed ANOVA | |||
| Main effect of pandemic | Q = 81.51 | <0.001 | |
| Main effect of day | Q = 622.17 | <0.001 | |
| Interaction | Q = 86.44 | <0.001 | |
| Follow‐up trimmed t tests | |||
| Pre‐pandemic: free day – workday | t(354.0) = 25.01 | <0.001 | 81.39 (74.99, 87.79) |
| First wave: free day – workday | t(354.0) = 18.95 | <0.001 | 54.91 (49.21, 60.61) |
| Workday: first wave – pre‐pandemic | t(354.0) = 11.58 | <0.001 | 32.81 (27.23, 38.38) |
| Free day: first wave – pre‐pandemic | t(354.0) = 2.71 | 0.007 | 6.32 (1.74, 10.91) |
| Sleep midpoint | |||
| Trimmed ANOVA | |||
| Main effect of pandemic | Q = 118.33 | <0.001 | |
| Main effect of day | Q = 576.49 | <0.001 | |
| Interaction | Q = 88.17 | <0.001 | |
| Follow‐up trimmed t tests | |||
| Pre‐pandemic: free day – workday | t(345.0) = 23.96 | <0.001 | 58.84 (54.01, 63.67) |
| First wave: free day – workday | t(345.0) = 18.69 | <0.001 | 39.54 (35.38, 43.70) |
| Workday: first wave – pre‐pandemic | t(345.0) = 13.08 | <0.001 | 28.66 (24.35, 32.97) |
Effect sizes and confidence intervals (CIs) are in minutes and reflect differences in the trimmed means of the conditions being compared.
Differences expressed in minutes with 95% CIs in brackets. Significant values bolded for emphasis. Pandemic effects refer to comparisons between pre‐pandemic to the first wave of the COVID‐19 pandemic. Day effects refer to comparisons between weekdays and free days.