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NAEP Technical DocumentationSampling Frame for the 2020 Private School Long-Term Trend Assessment
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The primary sampling frames for private schools were developed from the Private School Universe Survey (PSS) corresponding to the 2017-2018 school year. The PSS file is the Department of Education’s primary database of elementary and secondary private schools in the 50 states and the District of Columbia, and it is based on a survey conducted by the U.S. Census Bureau during the 2017-2018 school year. These sampling frames are referred to as the PSS-based sampling frames.
The PSS-based sampling frame was restricted to schools located in the
primary sampling units (PSUs) selected for the NAEP 2020
long-term trend (LTT) assessment. In addition, the sampling frame excluded ungraded schools, vocational schools with no enrollment, special-education-only schools, homeschool entities, prison and hospital schools, and juvenile correctional institutions. Vocational schools with no enrollment serve students who split their time between the vocational school and their home school.
The following table presents the number of schools and estimated enrollment for the private school frame by age population. The unweighted estimated enrollment is restricted to the selected PSUs. The weighted estimated enrollment incorporates the PSU weight (inverse of the probability of selecting the PSU) and the estimated age-eligible enrollment, and thus is a national estimate of the number of private school students in the age population. The age-eligible enrollment was estimated using age distribution fractions (see link above right) derived by grade for each age population.
| Age | Affiliation | Number of schools | Estimated enrollment (unweighted) | Estimated enrollment (weighted) |
|---|---|---|---|---|
| 9 | Total | 11,699 | 212,088 | 329,335 |
| Catholic | 2,829 | 80,372 | 121,588 | |
| Non-Catholic | 7,173 | 123,231 | 195,567 | |
| Unknown affiliation | 1,697 | 8,485 | 12,179 | |
| 13 | Total | 12,320 | 211,959 | 327,488 |
| Catholic | 3,413 | 84,123 | 123,437 | |
| Non-Catholic | 7,210 | 119,351 | 191,872 | |
| Unknown affiliation | 1,697 | 8,485 | 12,179 | |
| NOTE: Detail may not sum to totals due to rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2020 Long-Term Trend Assessment. | ||||
For quality control purposes, school and student counts from the sampling frame were compared to school and student counts from previous private school frames by grade (for grades 4 and 8). Comparisons were grade-based because recent NAEP cycles did not have age-based samples, and grade counts are a reasonable proxy for age counts for comparison purposes. No major discrepancies were found.
Last updated 18 March 2024 (PG)