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Scoring Subscales Using Multidimensional Item Response Theory Model, Christine E. Demars

Department of Graduate Psychology - Faculty Scholarship

Several methods for estimating item response theory scores for multiple subtests were compared. These methods included two multidimensional item response theory models: a bi­factor model where each subtest was a composite score based on the primary trait measured by the set of tests and a secondary trait measured by the individual subtest, and a model where the traits measured by the subtests were separate but correlated. Composite scores based on unidimensional item response theory, with each subtest borrowing information from the other subtest, as well as independent unidimensional scores for each subtest were also considered. Correlations among scores from all …