PASAT and components of WAIS-R performance: Convergent and discriminant validity

The Paced Auditory Serial Addition Task (PASAT) (Gronwall, 1977), a full-length Wechsler Adult Intelligence Scale-Revised (WAIS-R) (Wechsler, 1981), and the National Adult Reading Test (NART) (Nelson, 1982) were completed by a sample of 152 healthy participants. Principal components analysis revealed that PASAT's loading on general intelligence (g) was substantial (.72) and exceeded that of many WAIS-R subtests. Following rotation, PASAT loaded highly (.75) on the WAIS-R attention/concentration factor. Evaluation of nested confirmatory factor analytic models confirmed that, although PASAT is not independent of general intellectual ability, it still loaded significantly on attention/concentration (.44) when it was permitted to load simultaneously on g. Conventional normative data were provided for three age bands. In addition, regression equations were built to permit a quantitative comparison of individuals' obtained PASAT scores with their estimated premorbid PASAT scores (using NART and age as predictors) and with scores predicted from their current general level of intellectual ability (using WAIS-R IQ and age as predictors). Both these sets of predictor variables accounted for highly significant proportions of PASAT variance; Multiple R was .52 for the former and .66 for the latter.