NAEP Technical DocumentationStratification of Private Schools for the 2018 Technology and Engineering Literacy (TEL) Assessment

For the private school sampling frame file, schools were explicitly stratified by private school affiliation (Catholic, non-Catholic, and unknown affiliation). Private school affiliation was unknown for nonrespondents to the NCES Private School Universe Survey (PSS). Within private school type, separate implicit stratification schemes were used to sort schools in certainty primary sampling units (PSUs) and noncertainty PSUs. In all cases, the implicit stratification was achieved via a "serpentine sort".

Within each certainty PSU, the schools were hierarchically sorted by

• census region,
• urbanization classification (four categories based on urban-centric locale), and
• estimated grade enrollment.

Schools in noncertainty PSUs were hierarchically sorted by

• PSU stratum,
• urbanization classification (four categories based on urban-centric locale), and
• estimated grade enrollment.

Printer-friendly Version