Evaluation of learning-disabled students with the Differential Ability Scales (DAS)

Abstract

This study examined the performance characteristics of 83 school-identified learning-disabled (LD) children on the Differential Ability Scales (DAS). As a group, the children scored low on many subtests relative to normative data. Correlations between the DAS and archival Wechsler Intelligence Scale for Children-Revised (WISC-R) and achievement tests provided further evidence for DAS validity, although differences in the cognitive processes measured remain. Sixty percent showed a significant standard score discrepancy between the General Conceptual Ability (GCA) and at least one achievement test, based on the simple difference approach. Based on DAS ability-achievement discrepancy patterns, comparisons between more homogeneously defined groups yielded few differences that were independent of group definition criteria. The results from a cluster analysis (Ward's method) yielded two subgroups that differed in terms of their ability-achievement discrepancy. Numerical auditory-sequential recall (Recall of Digits) appeared to be equally problematic for the two subgroups. Overall, compared with previous DAS studies, fewer implications regarding cognitive processes underlying learning disability can be made with findings from this study. It remains unclear whether the cognitive characteristics measured by the DAS will facilitate or improve the educational diagnostic and intervention processes currently utilized with LD children.