WIAT subtest and composite predicted-achievement values based on WISC-III verbal and performance IQs

Abstract

Critical values tables for determining significant differences between Wechsler IQs and WIAT subtests and composites based on a predicted-achievement method are provided in the WIAT manual for the Full Scale IQ and have been constructed recently for Verbal and Performance IQs (Flanagan & Alfonso, 1993). In order to use these tables, however, a predicted achievement score(s) is required. The process of calculating predicted-achievement scores is time-consuming and may result in errors, especially when more than one ability-achievement comparison is warranted. The present paper provides tables of WIAT subtest and composite predicted-achievement standard scores based on WISC-III Verbal and Performance IQs. These tables allow examiners to determine quickly ability-achievement discrepancies based on WISC-III Verbal or Performance IQs when they are used in conjunction with the critical values tables provided in our earlier article. These tables are most useful for the accurate assessment and diagnosis of learning disabilities.