NAEP Technical Documentation2018 Public School Social Sciences Assessment

			Target Population Sampling Frame Stratification of Schools Sampling of Schools Substitute Schools Ineligible Schools Student Sample Selection

The NAEP 2018 sample design yielded nationally representative samples of public school students in grade 8 for social sciences 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 2018 sampling plan was designed to assess 46,800 eighth-graders in public schools for social sciences. These students were allocated among tests in civics, geography, and U.S. history. Target sample sizes were adjusted to reflect expected public school and student response and eligibility.

Schools on the sampling frame were explicitly stratified prior to sampling by PSU type (certainty/noncertainty). Within certainty PSUs, schools were implicitly stratified by census region, urbanization classification, race/ethnicity stratum, and estimated grade enrollment. Within noncertainty PSUs, schools were implicitly stratified by PSU stratum, urbanization classification, and race/ethnicity percentage.

From the stratified frame of public 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.

Additionally, American Indian, Alaska Native, Black, and Hispanic students were oversampled at moderate rates as follows. First, schools in a high American Indian/Alaska Native stratum (i.e., schools with more than five percent American Indian and Alaska Native students and at least five American Indian or Alaska Native students in the sample grade) were sampled at four times the rate (by quadrupling their measure of size) as schools not in a high American Indian/Alaska Native stratum to implement oversampling of American Indian and Alaska Native students. Second, schools not in a high American Indian/Alaska Native stratum but in a high Black/Hispanic stratum (i.e., schools that were not oversampled for American Indian and Alaska Native students and with more than 15 percent Black and Hispanic students and at least 10 Black or Hispanic students in the sample grade) were sampled at twice the rate (by doubling their measure of size) as schools not in a high Black/Hispanic stratum to implement oversampling of Black and Hispanic students.

Finally, schools in the Honolulu PSU were oversampled at twice the rate (by doubling their measure of size) as schools not in the Honolulu PSU. This was done to ensure at least one school was sampled from this PSU. The PSU was selected with certainty not due to its size, but because it is unique.

Each selected school in the public school sample provided a list of eligible enrolled students from which a systematic sample of students was drawn. Within each school, students were selected with equal probability.

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