Table 1.

Results from the measurement invariance testing.

	Model	Invariance level	Chi-2 (df)	RMSEA (90% CI)	CFI	TLI	ΔRMSEA	ΔCFI
Main analysis (ELSA: n = 3,246)	Bifactor model	Configural	1691 (357)	0.034 (0.032, 0.036)	0.981	0.975
		Scalar	1962 (441)	0.033 (0.031, 0.034)	0.978	0.977	0.001	−0.003
	Correlated factors model	Configural	1874 (375)	0.035 (0.034, 0.037)	0.978	0.973
		Scalar	2374 (429)	0.037 (0.036, 0.039)	0.972	0.970	−0.002	−0.006
Comparative analysis (CHARLS: n = 5,57l)	Bifactor model	Configural	2378 (234)	0.041 (0.039, 0.042)	0.958	0.945
		Scalar	2789 (289)	0.039 (0.038, 0.041)	0.951	0.948	0.002	−0.007
	Correlated factors model	Configural	2118 (253)	0.036 (0.035, 0.038)	0.963	0.956
		Scalar	2967 (289)	0.041 (0.039, 0.042)	0.947	0.944	−0.005	−0.016

Note. df: degrees of freedom; RMSEA: Root Mean Square Error of Approximation; CFI: Comparative Fit Index; TLI: Tucker-Lewis Index; ΔRMSEA: difference in RMSEA; ΔCFI: difference in TLI. Scalar invariance is usually deemed to hold if the difference between the configural model in the RMSEA (ΔRMSEA) and the Comparative Fit Index (CFI) is smaller than 0.015 and 0.010, respectively. Configural invariance is usually deemed to hold if the values of the root mean square error of approximation (RMSEA) and the Tucker-Lewis Index (TLI) for the configural model were below 0.060 and above 0.950, respectively (24).