Table 5.
Internal Consistency and Test–Retest Reliability of the WHO-5-C, SRHQ, and PHQ-4-C (N = 343)
| Scales | Cronbach’s α | McDonald’s ω | ICC (95% CI) | SEM | |||
|---|---|---|---|---|---|---|---|
| Baseline | Follow-Up | Baseline | Follow-Up | Baseline | Follow-Up | ||
| WHO-5-C | 0.907 (0.891, 0.922) | 0.934 (0.923, 0.945) | 0.908 (0.893, 0.924) | 0.935 (0.924, 0.946) | 0.803 (0.762, 0.838) | 7.810 | 8.209 |
| WHO-5-C01 | 0.883 (0.863, 0.903) | 0.915 (0.900, 0.929) | 0.885 (0.865, 0.905) | 0.915 (0.900, 0.930) | 0.796 (0.754, 0.832) | 6.578 | 6.875 |
| WHO-5-C02 | 0.877 (0.857, 0.898) | 0.914 (0.899, 0.929) | 0.881 (0.860, 0.901) | 0.915 (0.901, 0.930) | 0.799 (0.757, 0.834) | 6.394 | 6.682 |
| WHO-5-C03 | 0.865 (0.843, 0.888) | 0.906 (0.890, 0.921) | 0.865 (0.841, 0.888) | 0.904 (0.887, 0.921) | 0.785 (0.741, 0.822) | 6.484 | 6.820 |
| WHO-5-C04 | 0.905 (0.889, 0.921) | 0.930 (0.918, 0.942) | 0.905 (0.889, 0.922) | 0.931 (0.918, 0.943) | 0.791 (0.748, 0.828) | 6.521 | 6.772 |
| WHO-5-C05 | 0.898 (0.881, 0.916) | 0.930 (0.918, 0.942) | 0.900 (0.883, 0.918) | 0.931 (0.919, 0.943) | 0.798 (0.756, 0.833) | 6.347 | 6.712 |
| SRHQ | 0.727 | 0.805 | N/A | N/A | 0.749 (0.697, 0.793) | 0.637 | 0.675 |
| PHQ-4-C | 0.818 (0.786, 0.849) | 0.846 (0.820, 0.872) | 0.820 (0.789, 0.851) | 0.849 (0.823, 0.875) | 0.681 (0.620, 0.734) | 1.234 | 1.263 |
Note: The McDonald’s ω and the 95% CI of Cronbach’s α cannot be calculated due to the SRHQ containing only 2 items.
Abbreviations: WHO-5-C, Chinese World Health Organization-Five Well-Being Index; WHO-5-C01-05, item 01–05 of the WHO-5-C was deleted; SRHQ, Self-Rated Health Questionnaire; PHQ-4-C, Chinese Patient Health Questionnaire-4; ICC, intraclass correlation coefficient; CI, confidence interval; SEM, standard error of measurement, calculated as “SD × sqrt (1-ICC)”.