Information Brief 97-2

Making Good Admissions Decisions Using ACT Test Scores and High School Grades

Attending college costs between $6,000 and $15,000 each year. Yet, only about one-half of students complete a bachelor's degree within five years. Therefore, everyone has an important stake in making good decisions about enrolling in the right college.

Students' performance in first-year courses is an important part of their overall success in college. Students who succeed in their first-year courses usually progress to higher-level courses. On the other hand, students who are not successful in their first-year courses may be required to retake them, may be placed on academic probation, or may even drop out.

Students' academic preparation in high school is very important in determining whether they succeed later in college. The more college preparatory courses students take in high school, and the higher the grades they earn, the more likely they are to acquire the academic skills and knowledge they need for college. Of course, other, nonacademic factors are also important. Motivation, grades, cost, parental support, and other responsibilities affect the success of college students.

Colleges can measure students' academic preparation in different ways. Typically they use high school course work and grades, and scores on standardized tests like the ACT Assessment. High school grades have serious limitations, because high schools differ in curriculum, instruction, and grading practices. On the other hand, some people think standardized tests are poor measures of students' academic preparation. These concerns raise some important questions:

  1. How useful are ACT scores for identifying students who are likely to succeed in their first year of college?
  2. How useful are high school (HS) grades for identifying students who are likely to succeed in their first year of college?
  3. How does using ACT scores and HS grades in combination affect admissions decisions?

ACT staff answered these questions using data from 29 colleges in a Midwestern state. Each college had at least 60 enrolled students with both ACT Composite scores (range of 1 to 36) and HS grade averages (range of 0.0 to 4.0). The typical number of students who applied to each college was 453, with 168 completing their first year.

Students' Chances of Success

Figures 1 and 2 show a student's chances of earning a 2.0 or higher (or 3.0 or higher) first-year GPA, based on ACT Composite score (Figure 1) or HS grade average (Figure 2).

FIGURE 1. Chances of Success Using ACT Composite Score for Students in a Midwestern State

FIGURE 1. Chances of Success Using ACT Composite Score For Students in a Midwestern State

FIGURE 2. Chances of Success Using HS Grade Average for Students in a Midwestern State

FIGURE 2. Chances of Success Using HS Grade Average For Students in a Midwestern State

Figure 1 shows that a student with an ACT Composite score below 18 would have a small change of even a 2.0 or higher first-year GPA. A student with an ACT score of 22 or higher, on the other hand, would have a much greater chance of being successful. Figure 2 shows similar results for HS grade average. These results show that ACT Composite scores alone or HS grade averages alone are useful measures of a student's likely success in college.

Colleges can use chances of success information in making admissions decisions. Suppose a college decided that it wanted to admit only students with a 70% or higher chance of earning a 2.0 GPA. Figure 1 shows that students with ACT Composite scores of about 22 or higher would be admitted. Figure 2 shows that students with HS grade averages 3.2 or higher would be admitted. These students would have about a 28% chance of a 3.0 or higher GPA.

Figure 3 shows a student's chances of earning a 2.0 or higher first-year GPA using ACT Composite score and HS grade average in combination. Figure 4 shows similar information for a 3.0 or higher first-year GPA. The shaded areas show four different levels of chances.

FIGURE 3. Chances of 2.0 or Higher GPA Using Both ACT Composite Score and HS Grade Average

FIGURE 3. Chances of 2.0 or Higher GPA Using Both ACT Composite Score and HS Grade Average

A college can use this information to develop a sliding scale for admissions. Using the hypothetical rule of a 70% or higher chance of earning a 2.0 GPA, a student with an ACT Composite score of 18, rather than a 22, could be admitted, if he or she had a HS grade average of 3.4 or higher. On the other hand, a student with a HS grade average of 2.6, rather than a 3.2, could be admitted if he or she had an ACT Composite score of 29 or higher. Note, however, that a student with any particular HS grade average could have less than a 70% chance of earning a 2.0 or higher GPA, if the ACT Composite score were too low.

For most combinations of HS grade average and ACT Composite score, a student has greater than a 50% chance of a 2.0 or higher GPA. This is due to the grading practices used by many colleges, where very few students earn less than a 2.0 first-year GPA.

FIGURE 4. Chances of 3.0 or higher GPA Using Both ACT Composite Score and HS Grade Average

FIGURE 4. Chances of 3.0 or higher GPA Using Both ACT Composite Score and HS Grade Average

Discussion

Used alone, ACT Composite scores and high school grades are effective for identifying students' likely success during their first year in college. However, when colleges consider ACT Composite scores and high school grade averages in combination, students with lower high school grade averages can compensate by having higher ACT Composite scores, and vice versa. By using a sliding scale, admissions officials are using more information about each student, without changing their minimum chance of success for admitting students. When colleges use ACT Composite scores or high school grade averages by themselves, students who might otherwise be successful would not be admitted.

The figures above show students' likely success in college. However, students' actual success also depends on many nonacademic factors, such as their motivation to succeed and their educational goals. Students and colleges therefore need to consider these other, nonacademic factors in making admissions decisions.