The schools and students participating in NAEP assessments are selected to be representative of all schools nationally. The results from the assessed students are combined to provide accurate estimates of the overall performance of students in both public and private schools in the nation.
Because each school that participated in the assessment,
and each student assessed, represents a portion of the
population of interest, the results are weighted to account
for the disproportionate representation of the selected
sample. This includes oversampling of schools with high
concentrations of students from certain racial/ethnic groups
and the lower sampling rates of students who attend very
small private schools.
More information on sampling and weighting can be found in NAEP Technical Documentation.
Student sample sizes and target populations in NAEP U.S. history, by grade and type of school: 2010