ERIC Number: ED555595
Record Type: Non-Journal
Publication Date: 2013-Apr
Abstractor: As Provided
Reference Count: 19
A Comparison of Four Linear Equating Methods for the Common-Item Nonequivalent Groups Design Using Simulation Methods. ACT Research Report Series, 2013 (2)
Topczewski, Anna; Cui, Zhongmin; Woodruff, David; Chen, Hanwei; Fang, Yu
This paper investigates four methods of linear equating under the common item nonequivalent groups design. Three of the methods are well known: Tucker, Angoff-Levine, and Congeneric-Levine. A fourth method is presented as a variant of the Congeneric-Levine method. Using simulation data generated from the three-parameter logistic IRT model we compare the accuracy of the four methods under a variety of conditions involving group differences between the old and new groups. The sampling properties of the methods' parameter estimates are also investigated. The results indicate that the Tucker method is less accurate than the other three methods when group differences exist, especially when sample size is large (800). However, the Tucker method's gamma has the smallest sampling error, especially when sample size is small. Appended are: (1) Tables A1-A8; and (2) Figures B-1 through B-7.
Descriptors: Comparative Analysis, Equated Scores, Methods, Simulation, Item Response Theory, Accuracy, Sampling, Sample Size, Mathematics Tests, Language Tests, English
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Publication Type: Numerical/Quantitative Data; Reports - Research
Education Level: N/A
Authoring Institution: ACT, Inc.