Approaches for Forming Composite Scores Using Multiple Sets of ACT Scores
Over the years, many postsecondary institutions and high school counselors have asked us how they should use ACT test scores sent to them by students who have taken the ACT more than once. Historically, most colleges have used the scores earned on a student's highest single test administration when making admission, placement, and scholarship decisions. However, increasing numbers of students are taking the ACT more than once. Some postsecondary institutions use a student's most recent score. Other institutions "pick and choose," selecting the best scores a student has earned in each content area over the course of several test administrations and forming a combined highest composite score. So there are at least three separate approaches being used by postsecondary institutions considering multiple sets of ACT test scores. Are these approaches equally valid? Does it matter which is used? Does ACT recommend one approach? This webpage answers these and other frequently asked questions about ACT composite scores for students who have multiple sets of test scores.
What Is the ACT Composite Score?
The ACT consists of four tests: English, Mathematics, Reading, and Science. The score range for each of the four tests is 136. The composite score, as reported by ACT, is the average of the four test scores earned during a single test administration, rounded to the nearest whole number.
If one student receives test scores in English, Mathematics, Reading, and Science of 20, 15, 18, and 17, and another student receives scores of 15, 18, 17, and 20, both students would earn the same composite score18. Although it can be seen from the subject area scores that one student is stronger in English and Reading and the other is stronger in Mathematics and Science, the two 18s represent the same overall level of achievement. ACT therefore considers the two students' composite scores to be comparable.
Individual forms of the ACT tests are equated, a process that assures, for example, that a score of 19 on one form of the English Test represents the same level of achievement as a score of 19 on any other form of the English Test, no matter when the forms were administered. Further contributing to the comparability of scores across forms is the standardization of test administration: with the exception of tests administered with extended time for students who qualify for such accommodations, all forms of the ACT are taken within fixed time limits, in prescribed order, and under standard conditions.
What About the Writing Test?
The ACT also includes an optional Writing Test. Students who take the optional Writing Test on a test date receive two additional scores: A Combined English/Writing Test score, which is a scaled score, ranging from 136, that reflects their performance on the Writing Test and the English Test combined, and a Writing Test subscore ranging from 212 that reflects performance on the Writing Test only. The Combined English/Writing Test is always calculated using an English Test score and a Writing Test subscore that are earned in the same administration. (Unlike test scores, subscores cannot be combined across administrations.) The most recent Combined English/Writing score would appear to reflect the examinee's current level of achievement more accurately, while the highest score would recognize that students do not always perform at their best.
What Are Postsecondary Institutions Using as an ACT Composite Score for Students Who Have Multiple Sets of Test Scores?
A postsecondary institution may adopt a "most recent," "single highest," or "combined highest" approach in defining what ACT composite score it considers:
- The most recent composite score is simply the composite score obtained from the four test scores on a student's most recent test administration.
- The single highest composite score is the highest composite score a student has obtained in any single test administration.
- The combined highest composite score is the score obtained for a student who has tested more than once, by using the highest English, highest Mathematics, highest Reading, and highest Science scores to form an averageregardless of the administrations from which each score was obtained.
For example, John took the ACT three times, earning the following results:
John earned a most recent composite score of 21 (on the third test administration in October 2011). He earned a single highest composite score of 22 (on the second administration in June 2011). The scores from John's second English Test (22), third Mathematics Test (23), first Reading Test (23), and second Science Test (22) give him a combined highest composite score of 23.
Why Would Postsecondary Institutions Prefer One Approach Over Another?
Each approach has its advantages. The most recent composite score would seem to reflect the examinee's current level of achievement more accurately than the other approaches. The single highest composite score, on the other hand, allows for the fact that students do not always perform at their best. If, for example, a student had a poor night's sleep, suffered a sudden attack of nerves, or was preoccupied with a personal problem, the student's most recent test score may reflect his or her abilities less accurately than higher scores earned on an earlier test date. Use of the combined highest composite score might be defended on similar grounds.
Which Approach Does ACT Recommend?
We leave to the individual postsecondary institutions the decision of what approach is best for them, believing that they are in the best position to understand their unique needs and the context within which the scores are being used.
We use the most recent composite score in our own research. However, our data on current retesters has shown that students' ACT scores generally remain stable from one test administration to another, so there is little statistical difference between their single highest composite and most recent composite scores.
We have found that the combined highest composite score may overstate some students' abilities (in testing terminology, to "capitalize on positive measurement error"). However, in our most recent study, approximately 52% of the retesters had combined highest composite scores that were the same as their single highest composite score, and approximately another 42% had a combined highest composite score one point higher than their single highest composite score.
The only definition of a composite score that ACT recognizes is its own definition: an ACT composite score is the average of the four multiple-choice scale scores from a single administration. While the findings of our research do not suggest that using combined highest composite score results in large differences, our desire to base our research and reporting on the most accurate scores compels us to maintain our position that single highest or most recent are our recommended approaches.
ACT recommends that postsecondary institutions choosing to recalculate a combined highest ACT composite score include in the calculation only those individual ACT test scores that come from a test date when the student completed the full battery of ACT tests and earned an ACT composite score.
ACT recommends that postsecondary institutions always store each set of scores separately by test date and test location (e.g., April 2011 National). These identifying fields facilitate accurate updates to ACT scoresfor example, when scores are later changed or cancelled.
Which Approach Does the NCAA Use?
The NCAA uses the maximum sum of test scores, essentially a variant on the combined highest composite score, as part of the determination of whether students meet the association's initial-eligibility standards.
Should Students Take the ACT More Than Once?
Students who have taken additional relevant coursework since they last tested may wish to retest, since they have reason to suppose they will do better next time. Students who believe their previous scores do not accurately reflect their achievement may also wish to retest. If, for example, they were ill or otherwise indisposed when tested, or it they were unfamiliar with testing procedures, it is reasonable to expect that they may do better on retesting.