The Relative Predictive Validity of ACT Scores in and High School Grades in Making College Admission Decisions

©2008 by ACT, Inc. All rights reserved. The ACT® is a registered trademark of ACT, Inc., in the U.S.A. and other countries. IC 0508B4080 The Relative Predictive Validity of ACT Scores and High School Grades in Making College Admission Decisions Postsecondary institutions often consider students’ high school grades and ACT scores when making admission decisions. Historically, these two measures have been used because they are believed to predict students’ eventual success in college. An important question for institutions is which indicators of college success they should use to confirm the predictive validity of these two measures. The answer will vary depending on the institution’s educational mission and its admission goals. Despite such differing goals and missions, however, most institutions would view academic performance and college persistence as important indicators of success. This brief summarizes ACT research on the relative weights of ACT scores and high school grades for predicting college persistence as well as selected indicators of academic success in college. The results of these analyses are summarized in the table below.1 Table 1: Predominance of ACT Scores or High School Grades in Predicting College Success, by Indicator College Success Indicator Predictor First-year College GPA Enrollment/Retention Status Collegiate Academic Proficiency Final College GPA Degree-Attainment Level ACT Scores 9 9 9 9 High School Grades 9 9 9 Studies of first-year college GPA (ACT, 1998; Allen, Robbins, Casillas, & Oh, 2007) suggest that ACT scores and high school grades should carry approximately the same weight if an institution wants its admission criteria to reflect expected level of first-year academic performance.2 The combination of ACT Composite score and high school GPA provides greater accuracy of 1 For a more detailed summary, please see the Appendix. 2 Another study of the relative ability of ACT scores and high school grades to predict first-year college academic performance (Noble & Sawyer, 2002) suggests that ACT scores should carry greater weight than high school grades if an institution wants its admission criteria to reflect high levels of first-year college GPA (defined as 3.50 or 3.75, as compared with 2.00, 2.50, or 3.00). 2 admission decisions for most groups of students than using either measure alone.3 An analysis of college enrollment status (as of the second fall after high school graduation), as well as a study of college retention, i.e., re-enrollment in a second year at the same institution (Robbins, Allen, Casillas, Peterson, & Le, 2006), suggest that ACT scores and high school grades should carry approximately the same weight if an institution wants its admission criteria to reflect likelihood of persistence to year two of college. The results for enrollment were generally similar across racial/ethnic and family income groups, with ACT Composite score as the better predictor of enrollment for African American and low-income students. Collegiate academic proficiency studies conducted in mathematics and writing suggest that ACT scores should carry greater weight than high school grades if an institution wants its admission criteria to reflect expected level of academic proficiency in mathematics or writing beyond the first year of college. An analysis of final college GPA of college graduates suggests that high school grades should carry greater weight than ACT scores if an institution wants its admission criteria to reflect expected final GPA by college graduation. However, a similar analysis of degree-attainment level, using the same sample of college graduates, suggests that ACT scores should carry greater weight than high school grades if an institution wants its admission criteria to reflect ultimate level of degree attainment by the end of postsecondary education. Taken together, these studies suggest that if an institution wants its admission criteria to reflect collegiate academic proficiency or ultimate level of degree attainment, ACT scores should carry greater weight than high school grades. If an institution wants its admission criteria to reflect first-year college GPA or persistence to the second year, ACT scores and high school grades should carry approximately the same weight. And if an institution wants its admission criteria to reflect final college GPA, ACT scores should carry lesser weight than high school grades. Conclusion A postsecondary institution’s admission criteria should ideally be aligned with particular admission goals and with the educational mission of the institution. This brief has presented empirical evidence for how various kinds of alignments can be supported and validated by the relative predictive weights of ACT scores and high school grades for selected indicators of college success. Unlike some recent studies (e.g., Geiser & Santelices, 2007) that questio