About the Assessment: Participation Rates

The results from the 2010 National Assessment of Educational Progress (NAEP) geography assessment are based on nationally representative samples of public and nonpublic (private and Bureau of Indian Education schools) school students at grades 4, 8, and 12. Unlike NAEP assessments in other subjects such as reading, mathematics, and science, the geography assessment was not designed to report results for individual states. The results from the assessed students are combined to provide accurate estimates of the overall performance of students. 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. Read more technical information about weighting adjustments made at the school and student level.

To ensure unbiased samples, NAEP statistical standards require that participation rates for original school samples be 70 percent or higher to report national results separately for public and private schools. In instances where participation rates meet the 70 percent criterion but fall below 85 percent, a nonresponse bias analysis is conducted to determine if the responding sample is not representative of the population, thereby introducing the potential for nonresponse bias.

Before substituting other schools for originally sampled schools that declined to participate, the student-weighted school participation rates for the 2010 geography assessment were 96 percent for grade four (99 percent for public schools and 68 percent for private schools), 96 percent for grade eight (99 percent for public schools and 74 percent for private schools), and 89 percent for grade twelve (91 percent for public schools and 67 percent for private schools). Weighted student participation rates were 95 percent at grade four, 93 percent at grade eight, and 83 percent at grade twelve.

The nonresponse bias analysis for grade 8 private schools showed that, while the original responding school sample may not have been fully representative, the potential bias was reduced by including substitute schools and by adjusting the sampling weights to account for school nonresponse. After school substitution and nonresponse adjustments, a remaining potential bias was that schools in the Midwest were somewhat overrepresented in the final sample of grade 8 private schools (32 percent in the responding sample compared to 29 percent in the full sample) and Northeast schools were somewhat underrepresented (16 percent, compared to 21 percent in the full sample). At grades 4 and 12, the school participation rates for private schools fell below the standard for reporting.

An analysis was also performed to examine the potential for nonresponse bias introduced through student nonresponse in grade 12 public schools, where the weighted student response rate was 83 percent. The analysis showed that the sample of responding students differed from the original student sample with respect to gender, relative age and student disability status. After adjusting the sampling weights to account for student nonresponse, there was no evidence of substantial bias, with the nonresponse-adjusted estimates for three variables—race/ethnicity, student disability (SD) status, and English language learner (ELL) status—differing from the unadjusted estimates by 1 percent or less.

Learn more about geography sample design.