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.
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