The stability of psychometric "g," the general factor of intelligence, is investigated in simulated correlation matrices and in typical empirical data from a large battery of mental tests. "G" is robust and almost invariant across methods of analysis. A reasonable strategy for estimating "g" is suggested. (SLD)

Confirmatory factor analysis was used to test first- and second-order factor models on cognitive abilities and their invariance across samples of 234 male and 225 female secondary school students. Factor models suggest that males and females may use different problem-solving strategies for spatial analogies, matrices, and numerical problems. (SLD)