Beyond Correlations: Usefulness of High School GPA and Test Scores in Making College Admissions Decisions

Abstract

Correlational evidence suggests that high school GPA is better than admission test scores in predicting first-year college GPA, although test scores have incremental predictive validity. The usefulness of a selection variable in making admission decisions depends in part on its predictive validity, but also on institutions’ selectivity and definition of success. Analyses of data from 192 institutions suggest that high school GPA is more useful than admission test scores in situations involving low selectivity in admissions and minimal to average academic performance in college. In contrast, test scores are more useful than high school GPA in situations involving high selectivity and high academic performance. In nearly all contexts, test scores have incremental usefulness beyond high school GPA. Moreover, high school GPA by test score interactions are important in predicting academic success.

Notes

¹In principle, an institution could statistically adjust high school GPA for high school effects (such as in a hierarchical model), thereby making it more standardized. The practical benefits of doing this are limited, however, if admission test scores are also used (Willingham, 2005).

²Although some non-open-enrollment institutions have test-score-optional admission policies, most of them continue to use test scores, at least for some applicants (Breland et al., 2002). Furthermore, it is doubtful that any institution disregards high school GPA (or its transformation to high school rank) in its admission decisions.

³I thank Professor Joseph Rodgers, Vanderbilt University, for his suggestion to estimate interaction models.

⁴Alternatively, one could say that ACT-C is more predictive for students with high HSAvg than for students with low HSAvg.