. Author manuscript; available in PMC: 2026 Apr 1.

Published before final editing as: J R Stat Soc Ser A Stat Soc. 2025 Apr 1:10.1093/jrsssa/qnaf033. doi: 10.1093/jrsssa/qnaf033

Table 5.

Unidimensional versus two-dimensional exploratory latent class IRT models

model	Estimated Log likelihood	No. of parms.	AIC	BIC

3-classes
Unidimensional	−65, 675.85	19	131,389.7	131,543.3
Two-dimensional	−65, 505.40	20	131,050.8	131,212.5
−2LogL	340.9	1 dof
4-classes
Unidimensional	−65, 673.74	21	131,389.5	131,559.3
Two-dimensional	−65, 084.60	22	130,227.2	130,461.7
−2LogL	1,178.3	1 dof