Premorbid IQ estimates obtained by combining the NART and demographic variables: construct validity

793-796, 1989a) have recently built regression equations to estimate premorbid IQ from the National Adult Reading Test (Nelson, 1982) and demographic variables. The construct validity of this IQ estimate was examined in a sample of 151 non-clinical subjects. Factor analysis was performed on WAIS subtests and the NART/demographic estimate (NDE). The loadings of these variables on the first unrelated principal component (which represents g or general intelligence) was examined. The g loading of the NDE was 0.90, which was higher than any of the WAIS subtests. This result suggests that the NDE has very high construct validity and is superior to the NART alone as a measure of premorbid g