Excessive daytime sleepiness assessed by the Epworth Sleepiness Scale and its association with health related quality of life: a population-based study in China

Table 1 Item responses, item scores, reliability and validity of ESS

Item	Response		Item score		Cronbach's α	Factor analysis
Item	n	%	Median (Q1,Q3)	Mean (SD)	Cronbach's α	Factor analysis
ESS1	3025	94.12	1(0,2)	0.99(1.09)	0.78*	0.57
ESS2	3187	99.16	1(0,2)	0.99(1.07)	0.78*	0.55
ESS3	3169	98.60	0(0,1)	0.70(0.94)	0.77*	0.68
ESS4	3174	98.76	1(0,2)	0.96(1.08)	0.76*	0.69
ESS5	3143	97.79	2(0,2)	1.48(1.14)	0.79*	0.53
ESS6	3204	99.69	0(0,0)	0.15(0.48)	0.80*	0.44
ESS7	3190	99.25	0(0,2)	0.86(1.03)	0.77*	0.61
ESS8	3086	96.02	0(0,1)	0.69(0.97)	0.78*	0.61
Total	2906	90.42	6(3,10)	6.75(5.11)	0.80

ISSN: 1471-2458