Thesis (Ed. Spec.)--University of Wisconsin--Stout, 2003. / Includes bibliographical references.

The pupose of this study was to examine the validity of the Differential Abilities Scale with a gifted sample. Subjects consisted of 111 students identified as gifted by Indiana S-4. They were in grades 1 thru 6 and ranged in age from 6-8 to 12-11 with a mean age of 9-8. There were 60 females and 51 males who participated. Approximately, 1% of the population was minority which closely resembled the school population. Data from previously administered WISC-III and WIAT (The Psychological Corporation, 1992) were available for 21 of the 111 students.The first aspect of this study was to assess the construct validity of the DAS through investigation of the internal structure. Several different models were proposed. These analyses revealed that the proposed models were not good explanations of the relationships among obtained scores because convergence could not be obtained. A respecified two factor model was obtained where loadings on a Verbal Factor were constrained as recommended by Maxwell (1977). For this sample of gifted students a two-factor model with the first factor being primarily composed of Word Definitions was found to be a tenable one for the DAS.The second aspect of this study was to examine the convergent and predictive validity of the DAS by comparing these scores with the WISC-III and WIAT scores. Verbal factors for the two intelligence tests were the most highly correlated. Although there is overlap between the two intelligence measures, each test measures something unique. While one might expect these two instruments would not correlate perfectly, this correlation is lower than predicted.The DAS cognitive portion was more highly related to the other ability measure, the WISC-III, than it was to achievement as measured by the WIAT. In addition, achievement portions of both instruments were more highly related than they were to the ability measures. / Department of Educational Psychology

The purpose of this study was to determine if distinct subgroups of learning disabled children could be identified using a single, recently developed, instrument--the Differential Ability Scales (DAS). Ward's method of cluster analysis was used to group 83 school-verified learning disabled children from the standardization sample.These children were classified using the core, diagnostic, and achievement subtests of the DAS. Achievement subtest scores were transformed into T-scores with a mean of 50 and a standard deviation of 10 to provide scores on the same scale as the core and diagnostic subtests. Using similar units allowed all scores to contribute more equally during the clustering (Romesburg, 1984).The following six subgroups were identified: (a) generalized, (b) high functioning, (c) normal, (d) underachievement, (e) borderline, and (f) dyseidetic. Not all subgroups displayed the expected discrepancy between intelligence and achievement associated with the current definitions of LD. One subgroup had what might be described as a "normal" diagnostic profile on the DAS. These results were consistent with those of prior subtyping research (Lyon & Watson, 1981; Lyon et al., 1981) where "normal" subgroups were found. Another subgroup obtained General Conceptual Ability scores within the borderline range. Overall, children in this subgroup displayed consistently low scores on all the DAS subtests and achievement commensurate with general ability. In subsequent discriminant analyses, both achievement and diagnostic subtests were necessary for accuracy in classification.This study provided evidence as to the DAS's ability to differentially diagnose the learning disabled and provided distinct profiles for LD subgroups. Administration of the diagnostic subtests along with the score and achievement subtests can provide the clinician with valuable diagnostic information for LD. / Department of Educational Psychology

Intelligence testing has had a relatively long and controversial history, beginning with what is generally considered the first formal measure of intelligence, the Binet-Simon Scales (1916). Questions regarding possible cultural bias in these measures arose virtually simultaneously (e.g. Burt, 1921; Stern, 1914). Over the course of the twentieth and early twenty-first centuries, an abundance of intelligence measures have been developed, with many of them having several revisions, but the issue of test bias remains an important one, both in the professional literature and in the popular press (Reynolds & Lowe, 2009). A current intelligence measure in use, the Differential Ability Scales, Second Edition (DAS-II, Elliott, 2007), is a test with growing popularity for assessment of children and youth, not only for its ease of use, but also for its appeal to young children and its nonverbal composite (among other things). Consequently, it is essential that there be empirical evidence supporting the use of the DAS-II as an appropriate measure of cognitive abilities for children of varying backgrounds. The test publishers conducted extensive research with a representative sample during test development in an effort to ensure that the measure met adequate reliability and validity criteria; however, the issue of test bias, particularly regarding cultural or racial/ethnic groups, was not explicitly addressed. This issue was raised and examined with the original DAS by Keith, Quirk, Schartzer, and Elliott (1999), but with the significant changes made from the first edition to the second, there is no guaranty that the evidence from the earlier would necessarily apply to the latter. The current study investigated whether the DAS-II demonstrates systematic construct bias toward children and youth of any of four ethnic groups: Black, Hispanic, Asian, and White. Multi-group confirmatory factor analysis using data from the DAS-II standardization sample was used to assess whether criteria for increasingly strict levels of invariance were met across groups. Outcomes of this research contribute to an existing body of literature on test bias, as well as provide evidence regarding cross-group construct validity in the DAS-II. Ultimately the results of this study can be used to evaluate the appropriateness of the DAS-II for clinical use with certain ethnic groups and will help to emphasize further the importance of exploring these issues with all standardized tests. / text

There is no abstract available for this dissertation. / Department of Educational Psychology

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

Thesis, PlanA (M.S.)--University of Wisconsin--Stout, 2004. / Includes bibliographical references.