IQs are very strong but imperfect indicators of psychometric g: Results from joint confirmatory factor analysis
The most global score yielded by intelligence tests, IQs, are supported by substantial validity evidence and have historically been central to the identification of intellectual disabilities, learning disabilities, and giftedness. This study examined the extent to which IQs measure the ability they target, psychometric g. Data from three samples of children and adolescents (Ns = 200, 150, and 135) who completed varying pairs of individually administered, multidimensional intelligence tests were analyzed using a joint confirmatory factor analysis to generate correlations between IQs and general factors representing psychometric g. The resulting values, expressed as g loadings, for the six IQs ranged from.88 to.95 (M =92). The accuracy of IQs in measuring psychometric g, the meaning of reliable specific ability variance in IQs not accounted for by psychometric g, and the use of IQs in schools and related settings are discussed.
Psychology in the Schools
Farmer, R., Floyd, R., Reynolds, M., & Kranzler, J. (2014). IQs are very strong but imperfect indicators of psychometric g: Results from joint confirmatory factor analysis. Psychology in the Schools, 51 (8), 801-813. https://doi.org/10.1002/pits.21785