This report examines both the substantiveness and statistical significance of differences between mean American College Testing (ACT) Program assessment scale scores. The first part of the report describes the development and results of a method for interpreting the substantiveness of mean differences in terms of test items correctly answered. For…

This study focused on the relationship between high school students' course-taking patterns and their achievement of higher-order thinking skills. PLAN scores (in grade 10) and ACT Assessment scores (in grades 11 or 12) were collected for 73,818 students in 1,174 high schools. The findings show that, in a typical high school, eleventh- and…