Developing a Measure of General Academic Ability: An Application of Maximal Reliability and Optimal Linear Combination to High School Students' Scores.

This article is concerned with developing a measure of general academic ability (GAA) for high school graduates who apply to colleges, as well as with the identification of optimal weights of the GAA indicators in a linear combination that yields a composite score with maximal reliability and maximal predictive validity, employing the framework of the popular latent variable modeling methodology. The approach to achieving this goal is illustrated with data for 6,640 students with major in Science and 3,388 students with major in Art from colleges in Saudi Arabia. The indicators (observed measures) of the targeted GAA construct were selected from assessments that include the students' high school grade and their scores on two standardized tests developed by the National Center for Assessment in Higher Education in Saudi Arabia, General Aptitude Test (GAT) and Standardized Achievement Admission Test (SAAT).