A Bifactor Analysis for a Mode-of-Administration Effect |
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| Authors: | Mark Pomplun |
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| Institution: | 1. Community Unit School District (CUSD) 303 , St. Charles , Illinois, USA mpomplun@d303.org |
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| Abstract: | This study investigated the usefulness of the bifactor model in the investigation of score equivalence from computerized and paper-and-pencil formats of the same reading tests. Concerns about the equivalence of the paper-and-pencil and computerized formats were warranted because of the use of reading passages, computer unfamiliarity of primary school students, teacher versus computer administration of the tests, and slightly lower scores on the computerized format than on the paper-and-pencil format across all 4 grades. A confirmatory item factor analysis implemented through the bifactor model in TESTFACT indicated that the best-fitting model had a general factor as well as skill-group factors. This model was more consistent with the data than a model with 2 method factors, paper-and-pencil and computer administration. In addition, the general and skill factor loadings for most of the items were reasonable. Although several instances of negative loadings were found for items on the skill factors, these did not appear to have any practical importance. As a result, the bifactor model proved useful for studying paper-and-pencil and computerized score equivalence because of the reasonable results and delineation of loadings for the method and skill factors at the item level as well as for the general factor. |
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