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NAEP Technical Documentation2014 Private School Social Studies Assessment 


Target Population

Sampling Frame

Stratification of Schools

Sampling of Schools

Substitute Schools

Ineligible Schools

Student Sample Selection


The NAEP 2014 sample design yielded nationally representative samples of private school students in grade 8 through a three-stage approach: selection of primary sampling units (PSUs), selection of schools within strata, and selection of students within schools. The sample of schools was selected with probability proportional to a measure of size based on the estimated grade enrollment in the schools.

The 2014 sampling plan was designed to assess 2,600 eighth-graders. These students were allocated among tests in civics, geography, and U.S. history. Target sample sizes were adjusted to reflect expected private school and student response and eligibility.

Schools on the sampling frame were explicitly stratified prior to sampling by private school affiliation (Catholic, non-Catholic, and unaffiliated). Within affiliation type, schools were implicitly stratified by PSU type (certainty/noncertainty). In certainty PSUs, further stratification was by census region, urbanization classification, and estimated grade enrollment. In noncertainty PSUs, additional stratification was by PSU stratum, urbanization classification, and estimated grade enrollment.

From the stratified frame of private schools, systematic random samples of eighth-grade schools were drawn with probability proportional to a measure of size based on the estimated grade enrollment of the school in the relevant grade.  

Each selected school in the private school sample provided a list of eligible enrolled students from which a systematic, equal probability sample of students was drawn.

Last updated 14 April 2021 (SK)