Table 2.

Correlation and difference between accelerometer and parent‐reported measures

		Correlation coefficient (‘r’)	Difference in hours (accelerometer − parent), Mean (SE)
Sleep duration	Weekday	0.43***	−0.48 (0.061)***
	Weekend	0.19*	−0.66 (0.095)***
Sleep timing	Weekday bedtime	0.59***	0.56 (0.069)***
	Weekday wake time	0.54***	−0.091 (0.084)
	Weekend bedtime	0.56***	0.85 (0.056)***
	Weekend wake time	0.47***	0.36 (0.056)***

Two individuals do not have accelerometer‐measured weekend sleep values. Student's paired t‐test was used to test differences in hours between mean accelerometer and parent‐reported typical sleep values (accelerometer estimate minus parent estimate) for a given individual. A negative difference in sleep duration indicates that the accelerometer estimate is shorter than the parent estimate. A positive difference in sleep timing indicates that the accelerometer estimate is later than the parent estimate. Mean (SE) of the difference in hours are shown.

^* P < 0.05.

^** P < 0.01.

^*** P < 0.001.

SE, standard error.