Adaptive Behavior Scale Cognitive Triad: discrimination and classification of institutionalized mentally retarded adults.

The Leiter International Performance Scale, the Peabody Picture Vocabulary Test-Revised, and the Cognitive Triad of the Adaptive Behavior Scale were used to assess the intellectual functioning of 77 institutionalized mentally retarded adults. On the basis of their IQs, 30 were categorized as profoundly, 21 as severely, and 16 as moderately retarded (10 were unclassifiable because the Leiter and Peabody yielded disparate scores). Discriminant analysis in which category membership was predicted on the basis of the Cognitive Triad measures (Economic Activity, Language Development, and Number and Time Concepts) correctly classified 78% of the cases. There were no instances in which profoundly and moderately retarded individuals were mutually misclassified. Results support the use of the Cognitive Triad as an alternative for classifying lower functioning retarded persons.