PPVT IQ validity in adults: a measure of vocabulary, not of intelligence

Used partial correlation and multiple regression procedures to test the hypothesis that the PPVT IQ assesses more than vocabulary in adults. Ss were 84 inpatients from psychiatry and neurology wards. The relationships between the PPVT IQ and other measures of vocabulary, intelligence, memory, visual-motor speed and education were examined in the statistical analyses. Although these variables have significant simple correlations with the PPVT IQ, the multivariate analyses show that the Vocabulary Subtest of the WAIS-R is the only important variable. No other variable or variable combinations are able to account for further PPVT IQ variance after the effect of the Vocabulary Subtest is removed. The results support the use of the PPVT as a test of adult vocabulary, but not adult intelligence, and suggest that the PPVT may be useful as part of language assessment in patients with expressive language disorders.