Measurement invariance testing of the PHQ-9 in a multi-ethnic population in Europe: the HELIUS study

BMC Psychiatry

Table 3 Comparing the model fit of one-factor and two-factor models

	χ² (df)	RMSEA	CFI	Factor correlation
One factor
Model	4398.963 (27)*	0.084 (0.082–0.086)	0.978
With residual correlation items 1 and 2	3457.229 (26)*	0.075 (0.073–0.078)	0.983
With residual correlation items 1&2, 3&4	2798.221 (25)*	0.069 (0.067–0.071)	0.986
With residual correlation items 1&2, 3&4, 7&8	2220.704 (24)*	0.063 (0.061–0.065)	0.989
Two factors^a (somatic vs non-somatic)
Model	3304.548 (26)*	0.074 (0.072–0.076)	0.984	0.924
With residual correlation items 1 and 2	3130.413 (25)*	0.073 (0.071–0.075)	0.984	0.946
Two factors based on exploratory factor analysis^b
Model	2306.120 (25)*	0.063 (0.061–0.065)	0.989	0.871
With residual correlation items 1 and 2	1130.192 (24)*	0.045 (0.042–0.047)	0.994	0.875

*Significant χ² test (P < .001)
^aItems 3,4,5,7 and 8 loading on factor 1 and items 1,2,6 and 9 loading on factor 2
^bItems 1,3,4 and 5 loading on factor 1, and items 1,2,6,7,8 and 9 loading on factor 2

ISSN: 1471-244X