Information Brief 2000-2

Monitoring Changes in High School Average ACT Composite Scores Over Time

Two years ago ACT Information Brief No. 98-3, How Significant Are Changes In My School's Average ACT Composite Score Over Time?, provided a chart to help educators interpret the significance of their schools' average ACT Composite score change between the 1997 and 1998 ACT-tested graduating classes. The original chart, although limited to a comparison across only two years, was intended to provide a rationale for educators to address the question, "Does my school's current average ACT Composite score differ significantly from last year's result?" Or more specifically, "Should I be overly concerned about a drop of one-tenth of a point or happy about an average increase of one-tenth of a point?" The chart presented with this Information Brief has been enhanced so that changes in average ACT Composite scores can be evaluated across more than two years, thus increasing the ability to monitor trends in school performance.

School Average ACT Composite Score Changes: Caveats

The ACT Assessment is a curriculum-based achievement test designed to assess students' critical reasoning and higher-order thinking skills in four content areas: English, mathematics, reading, and science reasoning. These tests not only reflect students' acquired skills as a result of their high school course work, but they also measure students' preparation to undertake course work in college. Every summer ACT mails to each high school that had at least 30 ACT-tested graduates the previous spring a comprehensive ACT High School Profile Report. In this document is a summary of a school's average ACT Composite scores over the past five years.ACT recommends that educators refer to this trend information when evaluating school performance, rather than changes in a school's average ACT Composite score from one year to the next. The chart appearing with this Information Brief provides the basis for the evaluation of performance across years.

A school's overall average ACT Composite score is affected by a variety of school and non-school variables. The percentage of students completing the college core high school curriculum, the quality of instruction, counseling, and courses offered by a school are just a few examples of variables that schools control. Student motivation, study habits, parental support and guidance, changes in the number of ACT-tested graduates across years as well as changes in a school's student population are examples of non-school variables that can affect a school's results.

School averages tend to vary more from year to year if the number of ACT-tested graduates is small. Likewise, school averages tend to be more stable if the number of ACT-tested graduates is large. The chart is therefore broken down into five categories based on the number of ACT-tested graduates; it includes schools with at least thirty ACT-tested students for each of the past six years. For each school within a given category, the average ACT Composite score difference was calculated across successive years (for example, 1998 school average minus 1997 school average). Then the school average ACT Composite score differences within each category were ordered from highest to lowest and percentile ranks calculated.

The following example illustrates how to use the table.Suppose your school's average ACT Composite score difference was 0.6, and you had 73 ACT-tested graduates in 2000 and 65 in 1999. Locate the appropriate "Number of ACT-tested graduates" category, read down the column to 0.6 and read across to the first column listing the percentile ranks of score changes. For this example, the score change relative to the number of tested graduates for this school corresponds to the 75th percentile. That is, this average score difference is higher than 75% of all school average score changes in the same size category. If, for example, your school's score change was 0.5 for the same range of tested graduates, then this score difference would lie between the 50th and 75th percentile ranks. This difference is higher than that of 50% of the schools in the same size category.

Average ACT Composite Score Changes
Percentile rank of
school average score changes
Number of ACT-tested graduates
30 – 44 45 – 61 62 – 88 89 – 144  greater than or equal to 145
95th 1.8 1.5 1.4 1.1 0.9
90th 1.4 1.2 1.0 0.9 0.7
75th 0.8 0.7 0.6 0.5 0.4
50th 0.1 0.1 0.1 0.1 0.0
25th –0.6 –0.5 –0.5 –0.3 –0.3
10th –1.2 –1.0 –1.0 –0.8 –0.6
5th –1.5 –1.4 –1.2 –1.0 –0.9
Average change in school averages 0.07 0.05 0.03 0.05 0.03