Table 2.

Results of four-group item response theory analysis

Variable	No. of free parameters	Log-likelihood	Δχ2	df	P	Samplesize-adjusted BIC
Base model	83	−7,639.51	–	–	–	15,599.03
Gender analysis
Factor loadings and thresholds constrained	47	–7,669.52	58.10	36	.0112	15,520.25
Mean and variance constrained across gender	43	–7,673.01	6.97	4	.1376	15,511.83
Mean and variance constrained across all groups	41	−7,673.67	1.17	2	.5563	15,505.42
Ethnicity analysis
Factor loadings and thresholds constrained	47	–7,711.63	138.58	36	<.0001	15,604.46
Mean and variance constrained	43	–7,716.60	9.85	4	.0430	15,598.98

Notes: Bolded text indicates best-fitting model. BIC = Bayesian information criterion.