Comparison of the WAIS and WAIS—R: Different results for different IQ groups.

Abstract

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 WAIS-R 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. When an established test is revised, evaluation of the equivalence of the two forms is necessary. Since the publication of

A Comparison of WAIS‐R and WAIS‐III in the Lower IQ Range: Implications for Learning Disability Diagnosis

“…The main findings do not support those of Spitz (1989) or Spruill & Beck (1988) who found that the effect of the Flynn effect upon IQ scores reversed (producing a negative difference between IQ scores due to a higher, not a lower IQ score achieved on the most recent version of the IQ test) for those with a Full Scale IQ of <70. These authors tested differences between the WAIS and the WAIS-R. Spitz (1989) refers to Flynn (1985) for an explanation of these findings, suggesting that the disparity is due to a low number of individuals in the retarded range in the stratified samples of the WAIS tests causing discrepancies when converting raw scores into IQ scores.…”

“…Furthermore, the combination of samples in the analysis may have increased the amount of variance due to sample or design factors, rather than due to differences in IQ scores. Spruill & Beck (1988) produced the same findings reported by Spitz (1989) in a study design that did not have the same methodological limitations. WAIS and WAIS-R were concurrently administered to a sample of students of varying IQ levels applying for special education services (n ¼ 108).…”

“…Spruill & Beck (1988) produced the same findings reported by Spitz (1989) in a study design that did not have the same methodological limitations. WAIS and WAIS‐R were concurrently administered to a sample of students of varying IQ levels applying for special education services ( n = 108).…”

“…The Flynn effect was originally described in people of around average intelligence. Some researchers have found that the Flynn effect is uniform across the borderline (Full Scale IQ 70-80) and mental retardation (Full Scale IQ <70) intellectual ability levels (Kanaya et al 2001;Truscott & Frank 2001), but others have found it to be smaller in those with lower IQ, and that it can even reverse for those with scores in the learning disability range (Spruill & Beck 1988;Spitz 1989). Truscott & Frank (2001) analysed the Wechsler Intelligence Scale for Children-Revised (WISC-R; Wechsler 1974) and the more recent Wechsler Intelligence Scale for Children-Third Edition (WISC-III; Wechsler 1991) scores for a sample of children receiving special education because of learning difficulties (n ¼ 171).…”

“…Some researchers have found that the Flynn effect is uniform across the borderline (Full Scale IQ 70–80) and mental retardation (Full Scale IQ <70) intellectual ability levels (Kanaya et al. 2001; Truscott & Frank 2001), but others have found it to be smaller in those with lower IQ, and that it can even reverse for those with scores in the learning disability range (Spruill & Beck 1988; Spitz 1989).…”