Assessing psychometric properties and measurement invariance of the Sleep Quality Questionnaire among healthcare students

Table 2 Fit indices for three alternative CFA models of the SQQ (N = 595)

Model	χ² (df)	P	CFI	TLI	AIC	BIC	RMSEA (90% CI)
Baseline
Item 2 in the SDS^a	265.529 (34)	< 0.001	0.847	0.797	15,982.736	16,074.895	0.120 (0.108, 0.132)
Item 2 in the DSS^b	104.315 (34)	< 0.001	0.953	0.938	15,821.522	15,913.682	0.059 (0.046, 0.072)
Item 2 excluded^c	63.549 (26)	< 0.001	0.970	0.959	14,239.977	14,323.359	0.067 (0.055, 0.080)
Follow-up
Item 2 in the SDS^a	268.677 (34)	< 0.001	0.870	0.828	15,242.308	15,334.468	0.118 (0.106, 0.130)
Item 2 in the DSS^b	92.785 (34)	< 0.001	0.967	0.957	15,066.416	15,158.576	0.054 (0.041, 0.067)
Item 2 excluded^c	62.122 (26)	< 0.001	0.977	0.968	13,563.274	13,646.657	0.059 (0.047, 0.072)
Threshold	N/A	> 0.050	≥ 0.950	≥ 0.950	N/A	N/A	≤ 0.080

CFA confirmatory factor analysis, SQQ Sleep Quality Questionnaire, SDS Sleep Difficulty Subscale, DSS Daytime Sleepiness Subscale, χ² chi-square, df degrees of freedom, CFI comparative fit index, TLI Tucker-Lewis index, AIC Akaike information criterion, BIC Bayesian information criterion, RMSEA root mean square error of approximation, CI confidence interval, N/A not applicable
^aitem 2 belongs to the SDS (original structure)
^bitem 2 belongs to the DSS
^citem 2 excluded from the SQQ

ISSN: 2050-7283