An Empirically-Derived Index of High School Academic Rigor. ACT Working Paper 2017-5

We derived an index of high school academic rigor by optimizing the prediction of first-year college GPA based on high school courses taken, grades, and indicators of advanced coursework. Using a large data set (n~108,000) and nominal parameterization of high school course outcomes, the high school academic rigor (HSAR) index capitalizes on differential contributions across courses and nonlinear relationships between course grades and first-year college GPA (FYGPA). Test scores from 8th grade were incorporated in the model to isolate the effect of HSAR. High school courses with the largest contributions to FYGPA were English 11, English 10, Chemistry, and Algebra 2. Participation in AP, accelerated, or honors courses increased HSAR. The correlation of the HSAR index and FYGPA was 0.50 and 0.49 in two cross-validation samples. While the HSAR index was the strongest predictor of FYGPA, it only led to a modest improvement in overall prediction when combined with high school GPA (HSGPA) and ACT Composite score. The predictive strength of the HSAR index was consistent across different types of high schools and colleges, and subgroup differences in the HSAR index were smaller than subgroup differences in ACT Composite score. Implications for high school counselors, researchers, and postsecondary student service personnel are discussed.