ACT Composite Scores of Retested Students

Many students elect to take the ACT Assessment more than once. This paper is concerned with the typical changes in scores observed between students' first and second testings. Analyses were based on data from a sample of students who tested twice between 1989 and 1992. The scores of twice-tested females, males/ blacks, whites, and students who tested on particular national test dates were also studied. On average, students7 Composite scores increased by 0.8 scale score units from the first to the second testing. About one-third of the students' Composite scores increased by two or more units, and about one-fifth of the students' Composite scores declined. The analyses of subgroup data showed that given the same initial test scores, males were slightly more likely to earn a particular second score or higher than were females; whites were more likely to earn a particular second score or higher than were blacks; and students who tested late in the junior year of high school and again early in the senior year were more likely to earn a particular second score or higher than were students who first tested after October of the senior year. Other variables were also considered for their relationships to retest scores. Students' high school course work and high school rank were both practically and statistically significant predictors in nearly every model explored. This result suggests that students can improve their ACT Assessment scores by taking extensive course work in ACT-tested areas and by earning high grades. ACT COMPOSITE SCORES OF RETESTED STUDENTS During the past decade there has been a steady increase in the proportion of students who elect to repeat the ACT Assessment. According to internal ACT management reports, approximately 10% of ACT Assessment examinees tested at least twice between October 1983 and June 1985. This figure rose to 16% for the test dates between October 1986 and June 1988, and jumped to nearly 28% (based on slightly different criteria) for the test dates between October 1989 and June 1991. Among students who last tested in the 1992-93 academic year, the retest rate was slightly over 30%. Although most examinees who retest improve on their initial scores, some examinees experience a decrease. As more students take the ACT Assessment multiple times, educational researchers need to explain score changes in ways that students, parents, and counselors can readily understand. Depending on one's perspective, changes in true scores, as well as changes in observed scores, may be of interest. According to a standard model used by psychometricians, a person's observed score is equal to the sum of a "true score" and a random measurement error. The magnitude of the measurement error can be described in terms of probability. For example, the magnitude of the measurement error for the ACT Composite score is, with probability approximately . 95, less than 2 points. Therefore, an observed ACT Composite score is, with probability approximately . 95, within ±2 points of the true Composite score (ACT, 1989). An analogous statement can be made about changes in the scores of multiple-tested students: Assuming that measurement errors on different testing occasions are