The ACT as a Predictor of College Success
ACT Validity Claims
ACT asserts that its test is "one of several effective tools for evaluating your college and career readiness," and the organization has produced research to support this claim. An ACT paper published in 2012, for example, found ACT composite scores to be "effective for predicting long-term success at both four- and two-year institutions," citing evidence such as higher college GPAs and graduation rates for students with higher ACT scores. A 2016 ACT paper criticized test-optional university admission policies by asserting that test scores reliably explain variances in college performance among students with the similar high school grades: ". . . the results illustrate that test scores meaningfully discriminate among students with the same HSGPA [high school grade-point average]. Therefore, institutions that ignore test score information would in effect consider all applicants with the same HSGPA as having the same likelihood of being successful on campus; however, the results indicate that this is not the case." Critics of the ACT claim that research conducted by the organization has a predetermined ideological alignment and therefore cannot be regarded as objective.
Independent Studies of Correlations between ACT Scores and College Grades
Some independent researchers have a positive view of the predictive value of ACT scores. A 2010 paper authored at Princeton University considered the association of a number of variables, including ACT scores, with college GPA. According to the researchers, "it is clear that standardized admission test scores are statistically significant and substantively important predictors of college grades." Other researchers have come to different conclusions. A 2014 study of 33 test-optional universities found that students who chose not to submit standardized test scores had roughly the same average cumulative college GPA (2.83) as those who did submit test scores (2.88). The study included approximately 123,000 student records over eight academic years.
Independent Research on ACT Scores and College Graduation Rates
The connection between ACT scores and college graduation rates has also been explored by researchers. The authors of the 2010 Princeton paper cited above found no obvious links: "Admission test scores were not associated with the likelihood of graduating." The 2014 research on test-optional universities found almost no difference between the rates at which test score submitters and non-submitters graduated (less than 1%). A 2017 master's thesis written at Utah State University, on the other hand, found that ACT scores, specifically those for the English and Math sections, were "significant predictors" of graduation rates. This latter viewpoint at least partially comports with ACT claims about the validity of its assessments.
Correlations between ACT Scores and High School GPA
In a master's thesis written by a graduate student at Marietta College in 2006, the high school GPAs and ACT scores of undergraduate applicants from both public and private high schools were analyzed. Correlations between high school GPA and ACT scores were found for both groups, although the link was much stronger for public than for private school students (correlation coefficient of .542 versus .334). Public school students included in the study had an average high school GPA of 3.40 and a mean ACT composite score of 22, while for private school students, the averages were 3.24 and 23 respectively. This research roughly aligns with a study conducted by ACT in 2016, which showed an average high school GPA of 3.40 and an average ACT score of about 23 among approximately 187,000 students tested.
Validity Comparisons between the ACT, the SAT, and High School GPA
A Yale University professor examined the issue of how well ACT scores predicted SAT scores and vice versa in 2005. This researcher found a correlation coefficient of .77, indicating a high degree of predictive validity (student scores on one of these tests tended to be similar to scores on the other). A number of researchers have concluded that high school grades more effectively forecast college GPA than either of those tests. The 2014 study of test-optional schools noted above, for example, found that high school GPA "closely track[s]" college GPA. Furthermore, students with strong high school grades and lower test scores performed better in college than their peers with higher test scores and lower high school grades. ACT has responded to this type of research by asserting that test scores provide valuable additional information on college applicants, above and beyond what can be gleaned from high school grades alone.