Table 4.

Confirmatory factor analysis fit indices

Cohort	Model structure	Model #	Relative chisqa	RMSEAb	CFIc	TLId	NFIe	SRMRf	χ2 difference test
Postpartum half #1	6-factor	Mod1	1.454	0.062	0.870	0.839	0.692	0.078
	1-factor	Mod2	1.924	0.088	0.708	0.671	0.551	0.091
Is 6-factor better fit than 1-factor model?			Lower ✓	Lower ✓	Higher ✓	Higher ✓	Higher ✓	Lower ✓	χ2 diff=91.844 p=0.000 ****
Postpartum half #2	6-factor	Mod3	1.621	0.072	0.885	0.858	0.756	0.068
	1-factor	Mod4	1.635	0.073	0.871	0.854	0.729	0.071
Is 6-factor better fit than 1-factor model?			Lower ✓	Lower ✓	Higher ✓	Higher ✓	Higher ✓	Lower ✓	χ2 diff=24.796 p=0.037 *
After-postpartum	6-factor	Mod5	1.786	0.077	0.855	0.820	0.731	0.073
	1-factor	Mod6	2.066	0.090	0.783	0.756	0.658	0.084
Is 6-factor better fit than 1-factor model?			Lower ✓	Lower ✓	Higher ✓	Higher ✓	Higher ✓	Lower ✓	χ2 diff=67.515 p=0.000 ****
Clinical depression postpartum	6-factor	Mod7	1.237	0.052	0.853	0.818	0.566	0.079
	1-factor	Mod8	1.364	0.065	0.751	0.720	0.472	0.086
Is 6-factor better fit than 1-factor model?			Lower ✓	Lower ✓	Higher ✓	Higher ✓	Higher ✓	Lower ✓	χ2 diff=28.081 p=0.014 *

^aRelative chi-square is calculated as the chi-square statistic divided by the degrees of freedom. Lower values indicate better fit. Values < 2 are considered acceptable (Ullman, 2001), disqualifying Mod6.

^bThe root mean square error of approximation (RMSEA) is a noncentrality-based index, for which lower values indicate better fit. RMSEA values < 0.05 indicates close fit (Steiger, 1990), and values < 0.08 are considered acceptable (Browne, Cudeck, Bollen, & Long, 1993; Cangur & Ercan, 2015; Hooper, Coughlan, & Mullen, 2008), disqualifying Mod2 and Mod6.

^cThe comparative fit index (CFI) is another noncentrality-based index, for which higher values indicate better fit (Bentler, 1990). Values > 0.80 are considered acceptable (Sharma, Mukherjee, Kumar, & Dillon, 2005), disqualifying Mod2,6,8.

^dThe Tucker-Lewis index (TLI) is a relative fit index, for which higher values indicate better fit (Tucker & Lewis, 1973).

^eThe Normed Fit Index (NFI) is an incremental fit measure for which larger values indicate better fit (Bentler & Bonett, 1980).

^fThe standardized root mean square residual (SRMR) (Joreskog & Sorbom, 1981) is an absolute fit index for which lower values indicate better fit. Values ≤ .08 indicate good fit (L.-t. Hu & Bentler, 1998; L. t. Hu & Bentler, 1999), disqualifying Mod2,6,8.

Inspection of the standardized residual correlation tables revealed no patterns of fit problems, as no more than 2 of the 18 correlations for any individual item were significant at the 0.05 level. Modification indices were all small (<25.00) indicating no need to alter the models’ designs.

^*p<0.05

^**p<0.01

^***p<0.001