Computation of Wechsler Adult Intelligence Scale Revised factor scores: Equal and differential weights

Standard procedures for estimating factor scores for the Wechsler Adult Intelligence Scale-Revised (WAIS-R; D. Wechsler, 1981) involve equally weighted sums of the subtests that load most highly on the factor being estimated. We argue that factor scores derived in this manner lack discriminant validity; they are strongly biased toward g (the first unrotated factor) and away from the other 2 unrotated factors. If regression-like weights are applied to all of the WAIS-R subtests and the products are summed, the resulting differentially weighted factors give results that show similar convergent validity and much greater discriminant validity with respect to the original factors.