A Comparison of the Wechsler Adult Intelligence Scale-Revised (Wais-R) and the Peabody Picture Vocabulary Test-Revised (Ppvt-R) with Mentally Handicapped Adults

Thirty- two mentally handicapped adults living in group residential homes were administered the WAIS-R and the PPVT-R (Form L or M). The subjects were randomly divided into four experimental groups in which the forms and order of administration were counter-balanced. Based on previous research with earlier versions of these tests, it was hypothesized that the standard scores on the PPVT-R would be significantly lower than the WAIS-R FS IQ; and that the PPVT-R standard score would be significantly correlated with the WAIS-R IQs and that the correlations would follow the pattern of Verbal IQ > Full Scale IQ > Performance IQ. It was further hypothesized that there would be no significant difference between the standard score on Form L and Form M of the PPVT-R. Due to exceptionally low standard scores on the PPV T-R, analysis were completed on both standard scores and the test age equivalents. The results confirmed each hypothesis: standard scores on the PPVT-R were lower than WAIS-R IQ scores; both PPVT-R standard scores and test age equivalents correlated significantly with WAIS-R IQ scores; and there was no difference in the scores obtained on Form L and M of the PPVT-R.