Table 3.
Psychometric properties of the Motivation to Use CPAP Scale at scale level (n = 183)
| Psychometric testing | Factor 1 | Factor 2 | Suggested cutoff |
|---|---|---|---|
| Standard error of measurement | 1.54 | 1.51 | The smaller the better |
| Ceiling effects (%) | 0 | 5.7 | < 20 |
| Floor effects (%) | 0 | 0.5 | < 20 |
| Internal consistency (Cronbach’s α) | 0.83 | 0.78 | > 0.7 |
| Item separation reliability from Rasch | 0.96 | 0.90 | > 0.7 |
| Item separation index from Rasch | 4.65 | 3.04 | > 2 |
| Person separation reliability from Rasch | 0.73 | 0.73 | > 0.7 |
| Person separation index from Rasch | 2.30 | 2.63 | > 2 |