Table 1.

Items Used to Operationalize Sleep Variables in Each of the Sleep Diaries.

Bedtime
United States	Attempted to fall asleep at ___________ am pm (circle am or pm)
Australia	Went to bed last night at ____________ am pm (circle am or pm)
Qatar and United Kingdom	Time you went to bed ________ (example entry of 8:00 pm was given in first row)
Sleep onset latency
United States and Australia	Minutes until fell asleep _______________
Qatar and United Kingdom	Researcher calculated variable as difference in minutes between “Time you went to bed” and “Time you think you fell to sleep”
Wake time
United States and Australia	Finally woke at _______________ am pm (circle am or pm)
Qatar and United Kingdom	Time you woke up _________ (example entry of 6:00 am was given in first row)
Sleep duration
United States	Slept this much last night _______ hours and _______ minutes
Australia	Went to bed last night at ____________ am pm (circle am or pm)
Qatar and United Kingdom	Total sleep duration (hours and minutes) _________ (example entry of 9 h 30 min was given in the first row)

Units of measurement were clock times for bedtime and wake time, minutes for sleep onset latency, and hours and minutes for sleep duration.