. 2018 Mar 6;8(3):e018485. doi: 10.1136/bmjopen-2017-018485

Table 2.

Goodness-of-fit indices for the different models

Model	χ² (df)	χ²/df	CFI	AGFI	SRMR	RMSEA
M1a	4216.39 (517)	8.16	0.737	0.708	0.0802	0.095
M1b	1699.40 (503)	3.40	0.915	0.864	0.0696	0.055
M2a	4276.30 (521)	8.21	0.733	0.707	0.0852	0.095
M2b	1664.67 (508)	3.28	0.918	0.866	0.0659	0.053

Model fitting criteria were as followed: a CFI value of greater than 0.90 showed a psychometrically acceptable fit to the data; the value of AGFI ranged between 0 and 1, a value of 1 indicated a perfect fit; for the SRMR, values of 0.08 or lower represented good fit; the value of RMSEA should be below 0.06 to show good fit.

M1b: the modified first-order factor model; M2a: the second-order factor model; M2b: the modified second-order factor model; M1a: the first-order factor model.

AGFI, adjusted goodness-of-fit index; CFI, comparative fit index; RMSEA, root mean square error of approximation; SRMR, standard root mean square residual.