The simplified Chinese version of the Nonrestorative Sleep Scale in Chinese young adults and measurement invariance across language and age

Table 4 Model fit indices in confirmatory factor analysis of the Chinese NRSS

Level of measurement invariance	χ² statistic	Degrees of freedom	CFI	RMSEA (95% CI)	SRMR	△CFI	△RMSEA
Language (n = 1070, simplified Chinese: n = 570; traditional Chinese: n = 500)
Configural	269.945	96	0.993	0.058 (0.050, 0.067)	0.053
Metric	302.739	104	0.992	0.060 (0.052, 0.068)	0.056	0.001	0.002
Scalar	445.059	136	0.987	0.065 (0.059, 0.072)	0.053	0.005	0.005
Age (n = 1051, Adolescents: n = 481; Adults: n = 570)
Configural	209.309	96	0.995	0.047 (0.039, 0.056)	0.046
Metric	275.275	104	0.992	0.056 (0.048, 0.064)	0.052	0.003	0.009
Scalar	396.643	136	0.988	0.060 (0.054, 0.067)	0.048	0.004	0.004

NRSS: Nonrestorative Sleep Scale; CFI: comparative fit index; CI: confidence interval; RMSEA: root mean square error of approximation; SRMR: standardized root mean square residual

ISSN: 2050-7283