Addressing challenges of validity and internal consistency of mental health measures in a 27- year longitudinal cohort study – the Northern Swedish Cohort study

Table 4 Comparison of factor models (A = three-factor, B = two-factor, C = one-factor) at T1–T4

Model		N	χ ²	df	p	CFI	RMSEA	90 % CI for RMSEA	Range of factor loadings	Comparison	∆χ²	∆df	p
T1	A	929	242.13	116	<0.001	.97	.03	.03–.04	.39–.85
	B	929	316.70	118	<0.001	.95	.04	.04–.05	.39–.82	A vs. B	48.36	2	<0.001
	C	929	427.24	119	<0.001	.92	.05	.05–.06	.33–.81	B vs. C	62.14	1	<0.001
T2	A	929	239.75	116	<0.001	.98	.03	.03–.04	.42–.90
	B	929	363.63	118	<0.001	.95	.05	.04–.05	.41–.87	A vs. B	53.43	2	<0.001
	C	929	491.39	119	<0.001	.93	.06	.05–.06	.42–.86	B vs. C	59.28	1	<0.001
T3	A	921	335.01	116	<0.001	.99	.05	.04–.05	.45–.97
	B	921	491.34	118	<0.001	.98	.06	.05–.06	.45–.98	A vs. B	71.88	2	<0.001
	C	921	635.43	119	<0.001	.98	.07	.06–.07	.39–.98	B vs. C	59.04	1	<0.001
T4	A	929	439.58	116	<0.001	.97	.06	.05–.06	.48–.92
	B	929	485.53	118	<0.001	.97	.06	.05–.06	.48–.91	A vs. B	29.99	2	<0.001
	C	929	666.37	119	<0.001	.95	.07	.07–.08	.42–.90	B vs. C	84.05	1	<0.001

Note: A = the factors of anxiety symptoms, depressive symptoms, and FSS; B = the factors of internalised mental health and FSS; C = the factor of extended internalised mental health

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