The purpose of the present study was to investigate the construct validity of the Differential Ability Scales (DAS) with a mentally handicapped population. The DAS is an individually administered, standardized test of intelligence. The stated purposes of the DAS are to provide a composite measure of conceptual reasoning abilities for classification and placement decisions and to provide a reliable profile of relative strengths and weaknesses for diagnostic purposes. With these goals in mind, it follows that this cognitive measure would be used often with mentally handicapped students. The DAS was developed using an hierarchical model based upon exploratory and confirmatory factor analyses. The model assumes that ability measures or subtests will load on a general factor g and will form subfactors at a lower level. The model also assumes that as children get older, the number of subfactors will increase because of development and differentiation of abilities. How mentally handicapped children would fit into this model was the subject of the current research.Using a sample of 100 mildly and moderately handicapped children ages 8 years, 0 months to 17 years, 5 months, confirmatory factor analysis was used to explore the factor structure of the DAS with this population. Three separate models were investigated: Model I, in which a one factor solution was proposed, Model II, in which two factors, Verbal Ability and Nonverbal Ability, were proposed, and Model III, in which three factors, Verbal Ability, Nonverbal Reasoning Ability, and Spatial Ability, as proposed by the test's authors, were investigated. Results of the analyses support the use of a one factor interpretation when using the DAS with mentally handicapped students. In practice, only the broadest score, the General Conceptual Ability Score (GCA), can be interpreted with confidence. Further, case study investigation illustrates the inconsistencies encountered in scoring at the lower end of the norms, as well as in using the outof-level procedure proposed by the test's authors. / Department of Educational Psychology
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/179410 |
| Date | January 1995 |
| Creators | Parker, Kathy L. |
| Contributors | Gridley, Betty E. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | v, 87 leaves : ill. ; 28 cm. |
| Source | Virtual Press |
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