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How we estimate percentiles: Kentucky 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 Kentucky Department of Education (KDE) School Report Card results for the Kentucky Summative Assessment (KSA), for 2022 to 2026: grade 10 Reading and Mathematics, and grade 11 Science, Social Studies, On-Demand Writing and Editing and Mechanics. For each school, district and the state, KDE reports the percentage of students at each performance level (Novice, Apprentice, Proficient, Distinguished) as whole numbers. It does not report how many students were tested, so each group is treated as 100 students split by those percentages, and the average score shown is estimated from that split.

Who is counted

Reading and Mathematics: the grade 10 KSA tests, taken by 10th graders. Science, Social Studies, On-Demand Writing and Editing and Mechanics: the grade 11 KSA tests, taken by 11th graders. Each year counts the students with results on that test at that school that spring. Kentucky leaves out any group too small to report, so some small schools do not appear for some years. A percentile compares a score with that year’s takers of the same test.

The nine regional educational cooperatives that appear in some KDE files are service agencies, not school districts, so they are not shown.

Important: the public data does not contain individual student scores, only these group summaries. So no tool can compute a true rank of one student against every other student. What we provide is a well-grounded estimate.

How the percentile is estimated

Kentucky publishes the exact scale-score range for each performance level (for example, grade 10 Reading is Proficient at 513-528). Given a score, we:

  1. identify which performance 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.

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 performance level matches the level shares, centered on that estimated average score. It’s there to visualize the shape of the group’s scores. The level shares set the headline percentile (steps above); the curve only decides where inside the student’s own level the line falls.

Why estimates are still useful: the share of students at each level is real for each group. The only assumption is how scores are distributed inside a level, a small and bounded range. Across a whole school, district or the state, that assumption averages out well, so the comparison (“above or below average here versus statewide”) is reliable even though the exact percentile is approximate.

Cut scores

The score range for each level is on the score guides. Scores in Proficient and Distinguished meet Kentucky’s standard. All tests report on a 400-600 scale except Science, which moved to a 700-900 scale with new cut scores in 2025.

The ranges are from KDE’s “Student Performance Level Cut Scores” charts for 2021-22, 2024-25 and 2025-26. Every cell for the non-Science tests is identical in the first and the last chart, and Kentucky has kept these cut scores since its 2021-22 standard setting, so they are used for every year from 2022. Results before 2022 (the earlier K-PREP tests) are not included because their cut scores are not available.

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.

Limitations to keep in mind

This site stores nothing you type. Scores are used only in your browser to draw your charts.

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