What the adjusted cohort graduation rate measures
The four-year adjusted cohort graduation rate (ACGR) measures regular-diploma completion for an adjusted group that began ninth grade together. It is not graduates divided by all students enrolled at a high school. The NCES graduation-rate technical notes explain cohort additions, removals, and reporting rules.
Calculate the rate using the cohort
In a hypothetical adjusted cohort of 200 students, 180 regular-diploma graduates produce a 90% four-year ACGR. A school’s total enrollment of 800 is irrelevant to that calculation. Four-year and extended-year graduation rates should be labeled separately because they allow different completion windows.
Exact values and estimates need different labels
K12 Atlas release v2026.07 combines state and EDFacts coverage and retains estimate flags. The graduation data summary identifies 22,247 profile rows with a rate and 7,106 with an exact value. Do not describe every displayed percentage as an exact reported rate, or recover an exact graduate count from a rounded or estimated percentage.
Do not average school percentages into a state rate
A school with a cohort of 20 should not carry the same student weight as one with a cohort of 400. Use compatible graduate and adjusted-cohort totals when available. If only percentages are provided, an unweighted average describes those percentages; it is not the state’s official graduation rate.
Check coverage before interpreting a blank
Many elementary and middle schools do not have a graduating high-school cohort. Missing rates can also reflect unavailable or protected values. The complete public-school directory is therefore not the right denominator for graduation reporting coverage. Keep the cohort year, source, estimate flag, and school type with each observation. See the ACGR definition for a shorter reference.
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