Hostname: page-component-7b7567c8c-2n9c9 Total loading time: 0 Render date: 2026-11-15T05:59:20.609Z Has data issue: false hasContentIssue false

Item Response Theory with Estimation of the Latent Population Distribution Using Spline-Based Densities

Published online by Cambridge University Press:  01 January 2025

Carol M. Woods*
Affiliation:
Washington University in St. Louis
David Thissen
Affiliation:
University of North Carolina at Chapel Hill
*
Requests for reprints should be sent to Carol Woods, Washington University, Department of Psychology, Campus Box 1125, St. Louis, MO 63130-4899, USA. E-mail: cwoods@artsci.wustl.edu

Abstract

The purpose of this paper is to introduce a new method for fitting item response theory models with the latent population distribution estimated from the data using splines. A spline-based density estimation system provides a flexible alternative to existing procedures that use a normal distribution, or a different functional form, for the population distribution. A simulation study shows that the new procedure is feasible in practice, and that when the latent distribution is not well approximated as normal, two-parameter logistic (2PL) item parameter estimates and expected a posteriori scores (EAPs) can be improved over what they would be with the normal model. An example with real data compares the new method and the extant empirical histogram approach.

Information

Type
Original Paper
Copyright
Copyright © 2006 The Psychometric Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable