| Abstract: | Recently there has been an increasing level of interest in subtest scores, or subscores, for their potential diagnostic value. Haberman (2008 Haberman, S. J. 2008. When can subscores have value?. Journal of Educational and Behavioral Statistics, 33: 204–229. [Crossref], [Web of Science ®] , [Google Scholar]) suggested a method to determine if a subscore has added value over the total score. Researchers have often been interested in the performance of subgroups—for example, those based on gender or ethnicity—on subtests. Several researchers found that the difference in performance between the gender-based subgroups varied over the different subtests. In this article, we examine whether the added values of the subscores vary between subgroups using data from several operational tests, including an international English proficiency test. For these data sets, the added values of the subscores occasionally vary over the subgroups, but the added values of the augmented subscores are invariant over the subgroups. |
