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An Evaluation of the Kernel Equating Method: A Special Study With Pseudotests Constructed From Real Test Data NEAT EG KE

Author(s):
von Davier, Alina A.; Holland, Paul W.; Livingston, Samuel A.; Casabianca, Jodi; Grant, Mary C.; Martin, Kathleen
Publication Year:
2006
Report Number:
RR-06-02
Source:
ETS Research Report
Document Type:
Report
Page Count:
31
Subject/Key Words:
Non-Equivalent-Groups Anchor Test (NEAT) Design, Equivalent Groups (EG) Design, Kernel Equating (KE), Observed-Score Equating, Test Equating

Abstract

This study examines how closely the kernel equating (KE) method (von Davier, Holland, & Thayer, 2004a) approximates the results of other observed-score equating methods—equipercentile and linear equatings. The study used pseudotests constructed of item responses from a real test to simulate three equating designs: an equivalent groups (EG) design and two non-equivalent groups with anchor test (NEAT) designs, one with an internal anchor and another with an external anchor. To compare results, the study sets the equating function in the EG design as the equating criterion. In these examples, the KE results were very close to the results from the other equating methods. Moreover, in almost all situations investigated, the KE results were closer to the equating criterion.

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