Table 1.

Sleep facet measurement

Dimension	Domain	Assessment	Cut point
Regularity	Consistency of sleep duration	Difference between workday sleep duration and non-workday sleep duration	Irregular: absolute value > 60 minutes; Regular: absolute value ≤ 60 minutes
Satisfaction	Please indicate how often you experience each of the following:		Dissatisfied: sometimes, often, or almost always (on at least 1 of the 4 items) Satisfied: rarely or never (on all 4 items)
	Trouble falling asleep	Have trouble falling asleep.
	Nocturnal awakenings	Wake up during the night and have difficulty going back to sleep.
	Early awakenings	Wake up too early in the morning and be unable to get back to sleep.
	Unrested upon waking	Feel unrested during the day, no matter how many hours of sleep you had.
Alertness	Nap frequency	During a usual week, how many times do you nap for 5 minutes or more?	Many naps: > 2 Few naps: ≤ 2
Efficiency	Sleep latency	How long does it usually take you to fall asleep at bedtime?	Inefficient: > 30 minutes Efficient: ≤ 30 minutes
Duration	Workday sleep duration	How much sleep do you usually get at night (or in your main sleep period) on weekdays or workdays?	Suboptimal duration: ≤ 6 or ≥ 9 Optimal duration: > 6 & < 9

To conduct supplementary clustering analyses (i.e., LCA), the continuous sleep characteristics were dichotomized to reflect desirable and undesirable categories for each. These values were then used as indicators in LCA.