Table 3.

Two-factor solution: Factor loadings and communalities by principal components from the SHI

	Factor loadings
Item content	1	2	h 2
10. I sleep on an uncomfortable bed (for example: poor mattress or pillow, too much or not enough blankets).	.77	.06	.60
11. I sleep in an uncomfortable bedroom (for example: too bright, too stuffy, too hot, too cold, or too noisy).	.74	-.02	.55
12. I do important work before bedtime (for example: pay bills, schedule, or study).	.65	-.12	.43
7. I do something that may wake me up before bedtime (for example: play video games, use the internet, or clean).	.51	.23	.31
6. I use alcohol, tobacco, or caffeine within 4 hours of going to bed or after going to bed.	.50	.04	.25
13. I think, plan, or worry when I am in bed.	.49	.20	.28
9. I use my bed for things other than sleeping or sex (for example, watch television, read, eat, or study).	.43	.26	.25
4. I exercise to the point of sweating within 1 hour of going to bed.	.14	.06	.02
3. I get out of bed at different times from day to day.	.13	.83	.70
2. I go to bed at different times from day to day.	.13	.82	.69
5. I stay in bed longer than I should two or three times a week.	.06	.74	.55
1. I take daytime naps lasting two or more hours.	.00	.50	.25
8. I go to bed feeling stressed, angry, upset, or nervous.	.34	.46	.33

Note: Bold number indicates salient factor loading (≥.32); h ² indicates item communalities; SHI: Sleep Hygiene Index.