Hostname: page-component-7b7567c8c-wxvwp Total loading time: 0 Render date: 2026-11-14T12:15:17.007Z Has data issue: false hasContentIssue false

Asymptotic Identifiability of Nonparametric Item Response Models

Published online by Cambridge University Press:  01 January 2025

Jeffrey A. Douglas*
Affiliation:
Department of Statistics, University of Illinois
*
Requests for reprints should be sent to Jeffrey A. Douglas, 101 Illini Hall, 725 South Wright Street, Champaign, IL. E-Mail: jeffdoug@stat.uiuc.edu

Abstract

The identifiability of item response models with nonparametrically specified item characteristic curves is considered. Strict identifiability is achieved, with a fixed latent trait distribution, when only a single set of item characteristic curves can possibly generate the manifest distribution of the item responses. When item characteristic curves belong to a very general class, this property cannot be achieved. However, for assessments with many items, it is shown that all models for the manifest distribution have item characteristic curves that are very near one another and pointwise differences between them converge to zero at all values of the latent trait as the number of items increases. An upper bound for the rate at which this convergence takes place is given. The main result provides theoretical support to the practice of nonparametric item response modeling, by showing that models for long assessments have the property of asymptotic identifiability.

Information

Type
Articles
Copyright
Copyright © 2001 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