. 2018 Aug 28;8:12975. doi: 10.1038/s41598-018-31266-z

Table 3.

Correlation, mean absolute error, and concordance between sleep diary and accelerometer estimates (N = 3,752).

Parameter	Metric	HDCZA			L5 ± 6
Parameter	Metric	Value	t; DF	P	Value	t; DF	P
sleep onset time	Correlation in timing	0.78 (95% CI: 0.77–0.79)	76; 3750	**	0.66 (95% CI: 0.64–0.68)	54; 3750	**
sleep onset time	MAE (min)	39.9	76; 3750	**	93.3	54; 3750	**
waking time	Correlation in timing	0.81 (95% CI: 0.8–0.82)	84; 3750	**	0.68 (95% CI: 0.66–0.7)	57; 3750	**
waking time	MAE (min)	29.9	84; 3750	**	58.4	57; 3750	**
SPT-window	Correlation in duration	0.52 (95% CI: 0.5–0.55)	38; 3750	**	0.26 (95% CI: 0.23–0.29)	16; 3750	**
	MAE (min)	40	38; 3750	**	128.4	16; 3750	**
	c-statistic	0.95 (IQR: 0.94–0.98)	—	—	0.92 (IQR: 0.90–0.94)†	—	—

DF: Degrees of freedom; MAE: mean absolute error; min: minutes; *P < 0.005; **P < 0.0005; ^†−0.03 difference (95% CI for difference: −0.031; −0.029), t = −44, DF = 3751, P < 0.0005.