Table 2.
Accelerometer-measured sleep duration (h/day) of the participants across different levels of self-reported sleep duration (h/day) (n = 8,438)
| Self-reported sleep duration (h/day) | Frequency | Percentage | Underestimation1 (n = 1810, 21.5%) | Accurate estimation2 (n = 1630, 19.3%) | Overestimation3 (n = 4998, 59.2%) | Mean of accelerometer-measured sleep duration (h/day) | SD of accelerometer-measured sleep duration (h/day) |
|---|---|---|---|---|---|---|---|
| 3 | 61 | 0.7 | 53 (86.9%) | 8 (13.1%) | 0 (0.0%) | 5.39 | 1.49 |
| 4 | 350 | 4.1 | 227 (79.1%) | 61 (17.4%) | 12 (3.4%) | 5.69 | 1.44 |
| 5 | 854 | 10.1 | 431 (50.5%) | 243 (28.5%) | 180 (21.1%) | 5.74 | 1.51 |
| 6 | 1961 | 23.2 | 573 (29.2%) | 561 (28.6%) | 827 (42.2%) | 5.86 | 1.39 |
| 7 | 2254 | 26.7 | 308 (13.7%) | 484 (21.5%) | 1462 (64.9%) | 6.03 | 1.42 |
| 8 | 2285 | 27.1 | 152 (6.7%) | 237 (10.4%) | 1896 (83.0%) | 6.18 | 1.52 |
| 9 | 431 | 5.1 | 12 (2.8%) | 31 (7.2%) | 388 (90.0%) | 6.38 | 1.54 |
| 10 | 180 | 2.1 | 3 (1.7%) | 5 (2.8%) | 172 (95.6%) | 6.41 | 1.61 |
| 11 | 15 | 0.2 | 1 (6.7%) | 0 (0.0%) | 14 (93.3%) | 7.20 | 1.92 |
| 12 | 47 | 0.6 | 0 (0.0%) | 0 (0.0%) | 47 (100.0%) | 5.99 | 1.58 |
1Self-reported sleep duration—accelerometer-measured sleep duration < − 0.5 h/day
2 − 0.5 h/day ≤ self-reported sleep duration—accelerometer-measured sleep duration < 0.5 h/day
3Self-reported sleep duration—accelerometer-measured sleep duration ≥ 0.5 h/day