Five possible interpretations are given of very high correlations between scores on successively administered ability tests in a longitudinal sample of approximately 7,000 public school students tested in grades 5, 7, 9, and 11. At each of the four grades, students were given the appropriate level of the Sequential Test of Education Progress…

Methodologies were proposed for combining background and aptitude and/or achievement information in an approach to the classification problem using the concept of under- and overachievement. The methodologies were applied to independent samples from four high school curricula. The results suggest that when past achievement and/or aptitudes were…