The Cattell-Horn-Carroll (CHC) model is a comprehensive model of the major dimensions of individual differences that underlie performance on cognitive tests. Studies evaluating the generality of the CHC model across test batteries, age, gender, and culture were reviewed and found to be overwhelmingly supportive. However, less research is available…

Most of the individual difference variance in the population is found "within" families, yet studying the processes causing this variation is difficult due to confounds between genetic and nongenetic influences. Quasi-experiments can be used to test hypotheses regarding environment exposure (e.g., timing, duration) while controlling for…

The several statistical methods described for detecting test bias in terms of various internal features of a person's test performances and the test's construct validity can be applied to any groups in the population. But the evidence regarding groups other than U.S. blacks and whites is either lacking or is still too sketchy to permit any strong…