Academic grit scale for Chinese middle- and upper-grade primary school students: testing its factor structure and measurement invariance

Table 3 Goodness-of-fit statistics of measurement invariance for tested models

Model	S-B χ²	df	CFI	TLI	RMSEA	SRMR	Model Comparison	ΔS-Bχ² (Δdf)	Δ CFI
Measurement invariance across genders
Model 1: the one-factor model for boys (n = 935)	102.75	35	0.979	0.973	0.045	0.026	-	-	-
Model 2: the one-factor model for girls (n = 959)	90.90	35	0.986	0.982	0.041	0.021	-	-	-
Model 3: configural invariance	194.22	70	0.983	0.978	0.043	0.023	-	-	-
Model 4: metric invariance	210.05	79	0.982	0.979	0.042	0.026	4 vs. 3	15.84 (9)	− 0.001
Model 5: scalar invariance	230.52	88	0.980	0.980	0.041	0.027	5 vs. 4	20.46 (9)	− 0.002
Measurement invariance across grades
Model 6: the one-factor model for the 3rd graders (n = 371)	65.19	35	0.977	0.971	0.048	0.032	-	-	-
Model 7: the one-factor model l for the 4th graders (n = 557)	67.64	35	0.984	0.979	0.041	0.026	-	-	-
Model 8: the one-factor model for the 5th graders (n = 451)	73.50	35	0.979	0.973	0.049	0.028	-	-	-
Model 9: the one-factor model for the 6th graders (n = 515)	68.69	35	0.985	0.980	0.043	0.024	-	-	-
Model 10: configural invariance	275.08	140	0.982	0.976	0.045	0.027	-	-	-
Model 11: metric invariance	323.08	167	0.979	0.977	0.044	0.042	11 vs. 10	47.98 (27)	− 0.003
Model 12: scalar invariance	374.45	194	0.975	0.977	0.044	0.044	12 vs. 11	51.37 (27)	− 0.004

ISSN: 2050-7283