This paper uses administrative North Carolina data linked from high school to college and national surveys to characterize the largest contributor to the STEM gender gap: engineering. Disparities are the result of differential entry during high school or earlier rather than postsecondary exit. Differences in pre-college academic preparation…

Detecting unusual similarity in the item responses of a pair of examinees usually conditions on the pair's overall test performance (e.g., raw scores). Doing this, however, often requires assumptions about the invariance of other examinee pair characteristics. In this study, we examined the appropriateness of such assumptions about selected…

A computer scan of ACT Assessment records identified 3,427 sets of twins. The Hardy-Weinberg rule was used to estimate the proportion of monozygotic twins in the sample. Matrices of genetic and environmental influences were produced. The heaviest loadings were clearly in the genetic matrix. (SJL)