Exploratory factor analysis of loadings of the Jenkins Sleep Scale items
| Jenkins Sleep Scale items | Factor #1 | Uniqueness |
| Trouble falling asleep | 0.62 | 0.61 |
| Waking up but no trouble falling asleep again | 0.72 | 0.48 |
| Waking up and trouble falling asleep again | 0.79 | 0.37 |
| Waking up feeling tired | 0.63 | 0.60 |