Comparison of the WAIS and WAIS-R: Different Results for Different IQ Groups

Using a procedure that eliminated repetition of identical items, thus avoiding order effects, we administered the Wechsler Adult Intelligence Scale (WAIS) and the WAis-Revised to 108 subjects. AH correlations between the two tests were significant and similar to those reported in the WAISR manual. For the group as a whole, verbal, performance, and full scale IQ scores on the WAIS-R were significantly lower than their respective WAIS scores; however, this difference was not consistent across IQ levels. Subjects of both average and borderline intelligence had WAIS IQ scores significantly above their WAIS-R scores. For the mildly retarded subjects, the performance IQs were equal for the WAIS and WAIS-R, whereas the WAIS-R verbal and full scale IQ scores were higher than the corresponding WAIS IQ scores. However, these score differences were small (1 point) and of little practical value. The differences of moderately retarded subjects, on the other hand, were large and in the reverse direction: The WAIS-R IQ scores were significantly higher than the WAIS IQ scores. Clinical implications of these findings are discussed.