Definition
The Common Core of Data (CCD) is the NCES collection of public elementary and secondary school, district, and state education records. NCES Common Core of Data files provide year-specific directory and enrollment files. Private-school records come from a different collection; CCD is not a census of private schools.
School records and district records
A school identifier identifies a campus record; a district identifier identifies the local education agency. Keep both as text to preserve leading zeros. A district finance value attached to a school record remains district-level information.
Directory status is not a current enrollment guarantee
Check the selected file’s year, operational status, and inclusion rules. Openings, closures, and grade changes can affect which records appear. A directory row is an administrative record, not a rating, and a historical entry does not prove that a campus is operating today.
Using CCD with other sources
K12 Atlas uses CCD directory context alongside collection-specific staffing and program records. Keep each field’s source year rather than assigning every metric the directory year. Explore the school directory, CCD-to-CRDC joining guide, and enrollment comparison guide.