PREDICTING WAIS-R IQ PREMORBID ABILITY - COMBINING SUBTEST PERFORMANCE AND DEMOGRAPHIC VARIABLE PREDICTORS

The WAIS-R standardization sample was used to develop regression formu las designed to predict WAIS-R IQ scores. In contrast to previous appr oaches that focused on either ''hold'' measures or demographic variabl es as predictors of premorbid functioning, these two domains were used conjointly in the present study. WAIS-R subtests served os measures o f present ability, whereas age, race, sex, education, and occupation s erved as the demographic predictors. Because any WAIS-R subtest may be impaired following brain injury, no subtest(s) were determined a prio ri to be ''hold'' measure(s). Instead, 33 regression formulas were dev eloped, each combining 1 of the 11 WAIS-R subtests with demographic va riables, to predict IQ scores. The current equations generally doubled the amount of variance accounted for by demographic variables alone a nd accounted for more variance in WAIS-R IQs than any other currently available method of predicting premorbid cognitive functioning. Regres sion to the mean was not a significant problem. The regression equatio ns are reported to aid in the estimation of premorbid WAIS-R IQ. Table s of predictive accuracy are also presented.