Continuous norming of a multidimensional test with a higher-order 2PL-IRT model

Hannah Heister, University of Groningen

Co-authors: Casper J. Albers, University of Groningen; Marieke E. Timmerman, University of Groningen

Abstract: In this paper we introduce a higher-order two-parameter logistic item response theory model (HO-2PL-norm) that is of use to estimate norms for psychological tests covering various related domains. HO-2PL-norm models a age-dependent domain-specific distributions of the latent trait, with correlations that are constant across age. We present the theoretical details of the proposed model, and show, based on simulated data, that HO-2L-norm performs well, and consistently outperforms the method used in current practice.