Table 2.

Common measures from sleep tracking devices.

Sleep Measure	Acronym	Units	Abbreviated	Measurement	Description
Sleep Onset Latency	SOL	Minutes	mins	Derived	Number of minutes from Time at Lights Out to Time at Sleep Onset
Sleep Onset Time	SOT	Time of day	hh:mm	Directly measured	Time of day when the first epoch of sleep occurs between Time at Lights Out and Time at Wake
Total Sleep Time	TST	Hours and Minutes	h:min	Derived	Number of minutes from Time at Sleep Onset to Time at Wake, minus number of minutes awake (WASO)
Wake After Sleep Onset	WASO	Minutes	mins	Directly measured	Number of minutes awake after Time at Sleep Onset
Wake Time	WT	Time of day	hh:mm	Directly measured	Time of day when awake with no further Sleep Duration
Sleep Efficiency	SE	Percentage	%	Derived	Sleep Duration divided by Time in Bed multiplied by 100
Time in Bed	TIB	Hours and Minutes	h:min	Derived	The total time spent in bed, from Time at Lights Out to Time at Wake
Sleep Onset Variance	SOV	Hours and Minutes	h:min	Derived	Can be calculated using standard deviations or by using the sleep regularity index (SRI)
Wake Variance	WV	Hours and Minutes	h:min	Derived	Can be calculated using standard deviations or by using the sleep regularity index (SRI)