How we calculate everything
If you cannot check us, you should not trust us. Here is every input and every step, including the ones that make our numbers look less impressive.
Sources
- Money — US Census Bureau Annual Survey of School System Finances (F-33), fiscal year 2024. This is the only national source that reports pupil transportation and capital outlay for every district. Districts self-report to it.
- Enrolment, staffing, directory — NCES Common Core of Data, 2024, via the Urban Institute Education Data Portal under ODC-BY 1.0.
- Child poverty — Census SAIPE school-district estimates, 2024. We use this instead of free-and-reduced-lunch eligibility, which community eligibility has made useless for comparing districts.
- Price levels — BEA Regional Price Parities, metro-area where one exists and statewide otherwise. Each district's page says which it got.
The formulas
- Per student, as reported = current operating spending ÷ membership. Capital and debt service are excluded, always, and shown separately.
- Price-adjusted = the above ÷ (local price parity ÷ 100).
- Excluding transport = (current spending − pupil transportation) ÷ membership, then price-adjusted.
- Reaching classrooms = (instruction + instructional staff support) ÷ current spending.
- Percentile is against a cohort of districts with the same grade span and in the same enrolment decile — never against all 13,000 at once, which would only tell you that big suburban districts differ from small rural ones.
What we refuse to do
- We do not compare test scores across state lines. Each state writes its own test and sets its own passing mark. "72% proficient" in one state and "72% proficient" in another are two different measurements. The one research dataset that puts them on a common scale forbids commercial use, so we do not have it and we do not fake it.
- We do not call students-per-teacher "class size." It is total enrolment divided by teaching staff. Every real classroom is larger than that number.
- We do not estimate a missing figure. About 28% of districts in the federal directory have no F-33 filing. Their money rows are blank. A blank is information; an imputed number is a guess wearing a suit.
- We do not adjust for teacher pension accounting. Several states pay pensions centrally, so that cost never appears in a district's books and its spending looks lower than a neighbouring state's for a purely clerical reason. No arithmetic fixes this honestly, so we name it here instead of pretending it away.
Found an error?
Tell us which district, which figure, and what you believe it should be. Corrections that hold up get fixed in the next build and credited on this page.