Table 1.

Measurements and sample sizes by phase of study

Phase of study	Measurements	Sample size*
Phase 1	Morningness–Eveningness Questionnaire (MEQ)	2200
	Cambridge–Hopkins Restless Legs Questionnaire	2402
	Household sleep environment	2407
	Participated in at least one of Phase 1 sleep assessments	2425
Phase 2	Wrist actigraphy	899
	Home Sleep Test	619
	Pittsburgh Sleep Quality Index	1159
	Epworth Sleepiness Scale	1212
	Insomnia Severity Index	1212
	HOBO (light, temperature)	379
	Extech (sound)	354
	Participated in at least one of Phase 2 sleep assessments	1317

^*Number with valid data (see methods for the definition of valid by measurement type).