Exceptional LD Profile Types for the WISC-III and WIAT

Abstract

This study represents an extension of the research on subtypes of learning disabilities (LD). The studies on LD subtypes have consistently produced five or six distinct profiles. One weakness of previous studies was the assumption that identified individuals were accurately diagnosed. The current study examined ability and achievement profiles on the third edition of the Wechsler Intelligence Scale for Children (WISC-III) and Wechsler Individual Achievement Test (WIAT) for 201 students identified as LD. An initial hierarchical cluster analysis indicated five distinct clusters that were similar to those found in previous research. After the initial cluster analysis of all cases, the ability and achievement profiles were matched against the most common multivariate profiles of ability and achievement scores derived from the WISC-III/WIAT linking sample. Results revealed that 70.1% of the student profiles matched a core profile and could, therefore, be considered nonexceptional. A second cluster analysis of the cases, which were judged to have exceptional profiles, indicated that two distinct clusters were present. The ramifications of these findings on the identification of LD as well as the utility of exceptional profiles are discussed.