Usefulness of High School Average and ACT Scores in Making College Admissions Decisions
ACT Researcli Report Semes 2010-2Usefulness of High School Average and ACT Scores in Making College Admission DecisionsRichard SawyerACTAugust 2010 For additional copies write: ACT Research Report Series P.O. Box 168Iowa City, Iowa 52243-0168© 2010 by ACT, Inc. All rights reserved. Usefulness of High School Average and ACT Scores in Making College Admission DecisionsRichard Sawyer AbstractAmple correlational evidence indicates that high school GPA is usually better than admission test scores in predicting first-year college GPA, although test scores have incremental predictive validity. Many people conclude that this correlational evidence translates directly to usefulness in making admission decisions. The issue of usefulness is more complex than is implied by correlations or by other regression statistics, however.This paper considers two common goals in college admission: maximizing academic success and accurately identifying potentially successful applicants. The usefulness of selection variables in achieving these goals depends not only on the predictive strength of the selection variables (such as measured by correlations), but also on other factors, including the distribution of the selection variables in the applicant population, institutions’ selectivity, and their criteria for what constitutes success. This paper considers indicators of usefulness in achieving admission goals, and presents estimates of the indicators based on data from a large sample of four-year institutions.The results 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.The paper also presents evidence for two other interesting phenomena: Students use their high school GPAs and test scores to select the institutions they want to attend, and this selfselection may be more important than institutions’ selection in admissions. Moreover, high school GPA by test score interactions are important in predicting academic success. AcknowledgmentsThe author thanks Jeff Allen, Julie Noble, and Nancy Petersen for their helpful comments and suggestions on earlier drafts of this report. Usefulness of High School Average and ACT Scores in Making College AdmissionDecisionsConventional wisdom supported by ample evidence holds that high school grades are usually better than college admission test scores in predicting first-year college GPA, but test scores have incremental predictive validity. For example, Morgan (1989) calculated correlations of high school rank, high school grades, and SAT scores with first-year college GPA in a study encompassing the academic years 1976 - 1985. Over this time span, multiple correlations for high school rank and grades ranged from .48 to .52. These correlations were .06 to .14 higher than the corresponding multiple correlations for SAT scores, but were .05 to .07 lower than the corresponding multiple correlations for the high school and test score variables jointly. More recently, Kobrin, Patterson, Shaw, Mattem, and Barbuti (2008) reported correlations of .36 for high school GPA, .35 for SAT scores, and .46 for high school GPA and SAT scores jointly. Evidence for ACT scores (1999, 2008c) is similar: For the academic years 1970-1971 through 2006-2007, multiple correlations of high school subject-area grade averages with first-year college GPA ranged from .48 to .51. The high school grade average correlations were .01 lower to .08 higher than the corresponding ACT score correlations, and were .04 to .09 lower than the corresponding correlations for ACT scores and high school grades jointly.A plausible explanation of these results is that test publishers strive to make test scores direct measures of cognitive ability only. High school grades, in contrast, are composite measures of both cognitive ability and academically relevant behavior such as attendance, punctuality in turning in assignments, and participation in class (Stiggins, Frisbie, & Griswold, 1989; Brookhart, 1993; Cizek, Fitzgerald, & Rachor, 1995/1996; Noble, Roberts, & Sawyer, 2006). College grades are also composite measures of cognitive ability and academically relevant behavior (Allen, Robbins, Casillas, & Oh, 2008). For this reason, high school GPA should more strongly predict first-year college GPA than test scores do. Weighing in on the other s
