A Comparison of the Wechsler Adult Intelligence Scale-Revised with the Peabody Picture Vocabulary Test-Revised

The Peabody Picture Vocabulary Test (PPVT), a receptive vocabulary measure, and the Wechsler Adult Intelligence Scale (WAIS), a measure of general intelligence, have been two tests widely used by educators and psychologists, respectively. In addition to being used as a measure of receptive vocabulary, the PPVT was frequently used as a measure of intelligence. While the authors of the PPVT established IQ scores, this use of the PPVT frequently brought criticism from professional psychologists who felt that the test was not comprehensive enough to be used as a measure of general intelligence. The PPVT was revised in 1981, and the term IQ was no longer used as a descriptive term for the standardized scores. The authors clearly stated that the PPVT-R measured only one important facet of intelligence: receptive vocabulary. The revised version\u27s age range expanded to 2 1/2 through 40. The changes in the revision of the WAIS, also introduced in 1981, were not as significant as those of the PPVT-R. The WAIS-R was standardized for adults over the age of 16, so the PPVT-R and the WAIS-R share a larger age range (16-40) than did the original two versions (ages 16-18). The inclusion of adult norms on the PPVT-R make it possible to examine the relationship between receptive vocabulary (as measured by the PPVT-R) and general intelligence (as measured by the WAIS-R) for adults of average intelligence. Through this study, sixty subjects between the ages of 16 and 33 were compared on these two instruments. Subjects were volunteers drawn primarily from a college population. Correlations, regression equations, and standard errors of estimate were obtained for the Total sample: Males, Females, Younger (CA 16-23), and older (CA 24-33). Data from age by sex cells (Younger Males, Older Males, Youngei Females and Older Females) were also examined, but were interpreted cautiously due to the small sample size (N=15) in these cells. Results indicated that the PPVT-R (Form L) and WAIS-R (all three scales) have much commonality and significant correlations for all groups. There was one exception of a non-significant correlation with the Performance Scale for the Older group. The age by sex data revealed that the Older Female sub-group correlations between tests were not statistically significant. However, it was recognized that this sub-group was very restricted and probably not representative of females aged 24-33. Cautions regarding interpretation of the data are given. The lack of available information on comparison of these two frequently used tests leaves this area open for continued research