skip to main content skip to footer

Identifiability of Parameters in Item Response Models With Unconstrained Ability Distributions

Author(s):
Haberman, Shelby J.
Publication Year:
2005
Report Number:
RR-05-24
Source:
ETS Research Report
Document Type:
Report
Page Count:
22
Subject/Key Words:
Ability Distribution, Latent Variable, Cumulant Generating Function, Moments, Item Response Models

Abstract

If a parametric model for the ability distribution is not assumed, then the customary two-parameter and three-parameter logistic models for item response analysis present identifiability problems not encountered with the Rasch model. These problems impose substantial restrictions on possible models for ability distributions.

Read More