Hostname: page-component-7b7567c8c-wxvwp Total loading time: 0 Render date: 2026-11-13T21:51:24.734Z Has data issue: false hasContentIssue false

A Person Fit Test for IRT Models for Polytomous Items

Published online by Cambridge University Press:  01 January 2025

C. A. W. Glas*
Affiliation:
University of Twente, The Netherlands
Anna Villa T. Dagohoy
Affiliation:
University of Twente, The Netherlands
*
Requests for reprints should be sent to Cees A.W. Glas, Department of Research Methodology, Measurement and Data Analysis, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands. E-mail: c.a.w.glas@gw.utwente.nl

Abstract

A person fit test based on the Lagrange multiplier test is presented for three item response theory models for polytomous items: the generalized partial credit model, the sequential model, and the graded response model. The test can also be used in the framework of multidimensional ability parameters. It is shown that the Lagrange multiplier statistic can take both the effects of estimation of the item parameters and the estimation of the person parameters into account. The Lagrange multiplier statistic has an asymptotic χ2-distribution. The Type I error rate and power are investigated using simulation studies. Results show that test statistics that ignore the effects of estimation of the persons’ ability parameters have decreased Type I error rates and power. Incorporating a correction to account for the effects of the estimation of the persons’ ability parameters results in acceptable Type I error rates and power characteristics; incorporating a correction for the estimation of the item parameters has very little additional effect. It is investigated to what extent the three models give comparable results, both in the simulation studies and in an example using data from the NEO Personality Inventory-Revised.

Information

Type
Original Paper
Copyright
Copyright © 2007 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