ERIC Number: ED418999
Record Type: Non-Journal
Publication Date: 1998-Apr
Reference Count: N/A
An Evaluation of Multidimensional IRT Equating Methods by Assessing the Accuracy of Transforming Parameters onto a Target Test Metric.
Li, Yuan H.; Lissitz, Robert W.
The metric of the multidimensional item response theory (MIRT) item parameter estimates is usually referred to as reference axes that are orthogonal and of unit length. This is due to the fact that most MIRT parameter estimation programs solve the identification problem by requiring that multidimensional abilities be distributed as multivariate normal distribution, N (0, I). Under this circumstance, the equated group's reference system can be transformed into the base group's reference system by a composite transformation: an orthogonal procrustes rotation, a translation transformation, and a single dilation. Based on this composite transformation, three sets of MIRT equating methods have been developed and evaluated in this study. The results indicate that the best MIRT equating method is an unbiased, effective, and consistent estimator producing accurate transformation parameter estimates when the errors in the estimation of item parameters were purposely manipulated. In addition, this MIRT equating method is capable of successfully recovering parameters, especially for the item parameters, under well-fitting model conditions. (Contains 17 figures, 4 tables, and 35 references.) (Author/SLD)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A