Psychometric evaluation of the depression, anxiety, and stress scale-21 (DASS-21) among Chinese primary and middle school teachers

Table 4 Fit indexes in measurement invariance across different times

Model	χ²	df	CFI	RMSEA	SRMR	Δχ²	Δdf	ΔCFI	ΔRMSEA	ΔSRMR
Configural Invariance	2860.18	783	0.996	0.040	0.037	-	-	-	-	-
Thresholds constrained	2915.12	801	0.996	0.040	0.036	54.94	18	0	0	-0.001
Thresholds and loadings constrained	2955.47	819	0.995	0.039	0.042	40.35	18	-0.001	-0.001	0.006
Thresholds, loadings, and intercept constrained	2964.54	822	0.995	0.040	0.042	9.07	3	0	0.001	0
Thresholds, loadings, intercept, and residuals constrained	3014.32	843	0.995	0.039	0.043	49.78	21	0	-0.001	0.001

Notes: CFI = comparative fit index; RMSEA = root mean square error of approximation; SRMR = standardized root mean square residual

ISSN: 2050-7283