Table 3.

Goodness-of-fit indices of all models.

	Model chi-square				RMSEA (90% CI)	NFI	NNFI	CFI	GFI	SRMR
Model	χ2	df	n	p
Total sample	39.44	18	451	0.003	0.05 (0.03; 0.07)	0.98	0.97	0.99	0.98	0.04
Group A: 0–24 months	23.02	18	280	0.19	0.03 (0.00; 0.07)	0.98	0.99	0.99	0.98	0.04
Group B: 25+ months	33.16	18	171	0.02	0.07 (0.03; 0.11)	0.95	0.94	0.97	0.96	0.07
Multi-sample: Same pattern (parameters varying between models)	57.95	36	451	0.02	0.05 (0.03; 0.08)	0.96	0.97	0.98
Multi-sample: Invariance (parameters constrained to be equal across groups)	175.25	63	451	0.0001	0.09 (0.07; 0.11)	0.90	0.92	0.93
Model comparisons	Δχ2	Δdf		p
Mtotalsample – Msamepattern	18.51	18		0.42
Mtotalsample – Minvariance	135.81	45		<0.0001
Msamepattern – Minvariance	117.30	27		<0.0001

Same pattern = Path model illustrated in Figure 1 fitted to both groups simultaneously, allowing estimates to vary between groups (i.e., within-group parameters estimated). Invariance = Path model illustrated in Figure 1 fitted to both groups simultaneously, with model estimates constrained to be equal across groups (i.e., common parameters estimated for both groups).