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Linking Parameter Estimates Derived From an Item Response Model Through Separate Calibrations GPCM IRT

Author(s):
Haberman, Shelby J.
Publication Year:
2009
Report Number:
RR-09-40
Source:
ETS Research Report
Document Type:
Report
Page Count:
9
Subject/Key Words:
Generalized Partial-Credit Model (GPCM), Two-Parameter Logistic Model, Regression Analysis, Item Response Theory (IRT)

Abstract

A regression procedure is developed to link simultaneously a very large number of item response theory (IRT) parameter estimates obtained from a large number of test forms, where each form has been separately calibrated and where forms can be linked on a pairwise basis by means of common items. An application is made to forms in which a two-parameter logistic model is applied to dichotomous items and a general partial credit model is applied to polytomous items.

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