How we estimate percentiles: Alabama high school

A clear explanation of the data and the method, so you can judge how much weight to give the numbers.

What the data is

Every number here comes from the yearly test-results files of the Alabama State Department of Education for Alabama’s high-school state test, the ACT with Writing that juniors take at school: English Language Arts (2021 to 2026), Math and Science (2019 and 2021 to 2026), and, in 2019, ACT English. For each school, school system and the state, and for each test and year, these files give:

• the share of students in each of Alabama’s four levels, to two decimal places. Alabama does not publish how many students tested, so we work that number out from the shares themselves: only certain group sizes produce a given set of two-decimal percentages (64.29%, 28.57% and 7.14% are 9, 4 and 1 students out of 14). When more than one size fits (14 and 28 students give the same percentages), we take the one closest to the school’s grade 11 enrollment in federal school records, and we make each school system’s students add up to its schools. Checked against federal counts for 2019 and 2021, this gives the exact number of students for 99% of schools, and the statewide totals land within half a percent of Alabama’s own counts every year. That is why the tool says “about” before a number of students; and
• from those counts, an estimated average score: the center of the bell curve that best matches the share of students below each level’s cut score.

Who is counted

These are Alabama’s grade 11 ACT results: Alabama gives the ACT with Writing to every public-school junior at school in the spring as its state test. A small share of juniors (about 1 in 70) take Alabama’s alternate assessment instead, and Alabama reports their levels in the same results, so they are included. English Language Arts uses the ACT ELA score, the average of a student’s English, Reading and Writing scores, so it counts only students who took all three. In 2019 Alabama reported the ACT English score instead, on its own levels. Scores from weekend ACT tests are not included.

A percentile here compares a score with the Alabama juniors who took the ACT at school that spring (about 52,000 students in Math and Science in 2026, and about 2% fewer in English Language Arts, because it needs the writing test). It is not the same as the national rank on an ACT score report, which compares a score with test takers across the country.

The statewide row is Alabama’s own statewide result for public schools, including charter schools, which Alabama reports as their own school systems.

How the percentile is estimated

Alabama publishes the exact ACT score range for each of its levels (for example, for ACT Math, Level 3 is 19-24, and for English Language Arts, Level 3 is 19-22). Given a score, we:

1. identify which level the score falls in;
2. count everyone in the lower levels as scoring below;
3. within the score's own level, spread that level's students along the group's fitted curve (below) rather than evenly across the level's range. Students bunch up toward the middle of the scale, so an even spread would put too many of them out at the far ends of the lowest and highest levels. Checked against published statewide score distributions, this lands within about one percentile point of the true value for a typical score.

That gives the percentile: the estimated share of students in the group who scored at or below the entered score.

About the smooth curve

The bell-like curve on each chart is a truncated-normal distribution fitted so that its area within each level matches the level counts, centered on that estimated average score. It's there to visualize the shape of the group's scores. The level counts set the headline percentile (steps above); the curve only decides where inside the student's own level the line falls.

When a group's students all sit in one or two levels, the counts can't say how spread out their scores are. A curve that comes out too narrow is drawn no narrower than one fifth of the statewide spread, and inside the student's level the percentile spreads that level's students evenly instead. About one school result in thirty (most often a school where nearly every student is in Level 1) gets a wide default curve instead, which places a score inside its level close to an even spread.

ACT scores are whole numbers from 1 to 36, and some of Alabama’s levels span only three or four scores (Math Level 2 is 16-18), so many students share each score. The curve is smooth, but the scores it describes are not.

Cut scores

The ACT reports each subject on a 1-36 scale. Alabama sets its own four levels on it, labeled Level 1 to Level 4; scoring in Level 3 or 4 counts as proficient. From 2021 to 2026 the levels are: English Language Arts 1-13, 14-18, 19-22 and 23-36; Math 1-15, 16-18, 19-24 and 25-36; Science 1-15, 16-19, 20-25 and 26-36. They come from the Alabama State Department of Education’s yearly “Alabama Proficiency Levels” tables, which print the same ACT levels in every edition from 2020-2021 to 2025-2026.

In 2019 Alabama used different levels, set on each ACT subject score: English 1-14, 15-17, 18-24 and 25-36; Math 1-14, 15-16, 17-24 and 25-36; Science 1-16, 17-18, 19-23 and 24-36. They come from the department’s May 2019 “2018-2019 Alabama Benchmark Scores” memo. That year there was no English Language Arts score, which is why 2019 shows ACT English as its own test. Percentiles still compare fairly within each year.

Spring 2026 was the first time Alabama juniors took ACT’s redesigned, shorter test. ACT kept the same 1-36 scale, Alabama kept the writing and science sections, and Alabama’s 2025-2026 table keeps the same levels. The score range for each level, by year, is on the score guides.

The high-school progress report

The paid progress report puts every high-school test your child took in one table, with the percentile at each level from the school to the state, and charts each subject across the years.

• Each subject is a line. Every Alabama high-school test here is the grade 11 ACT, taken by every junior, so a subject’s results line up with your child’s earlier years in the same subject.
• Earlier years are compared statewide only. You can add your child’s grades 3-8 scores in the same subjects. The tool doesn’t know which middle school or school system they attended, so those years are compared with every student in the state in that grade, not with this high school or its school system.
• The report opens on the statewide view, the one level with a result for every test.

Limitations to keep in mind

• Percentiles are estimates, not official rankings. Treat a "62nd percentile" as "roughly the top 40%," not an exact standing.
• The number of students is estimated from the published percentages. For about one school in a hundred it may be off by a multiple (28 students shown as 14, say); the shares, and so the comparison, are the same either way.
• Small schools have small counts, so their estimates are noisier.
• Alabama hides the results of very small groups to protect students’ privacy, and those schools won’t appear (about one school result in forty-five, mostly special-education centers and alternative or virtual programs with only a few juniors). The school-system and state results still count those students.
• In 2021 fewer juniors tested than usual (about 90% of juniors for English Language Arts and 92% for Math and Science, against 93-98% in later years).
• Not included: 2018 (Alabama posted no school-level file), 2020 (no test, COVID), the grade 10 PreACT, the grade 12 ACT WorkKeys, and the alternate assessment as a test of its own.
• Alabama is compared at the school, school system, and state levels. Its county, city and charter school systems are peer districts, so there is no separate county tier.

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