Of the 176 schools sampled for PIRLS 2016 in the United States, four schools were marked ineligible because they had closed or did not have any enrolled fourth-grade students. Replacement schools are not to be used as a substitute for schools that are closed or ineligible due to lack of students in the target grade.
Of the remaining 172 schools, a total of 131 original schools participated in PIRLS 2016 for an unweighted response rate of 76 percent. The weighted school response rate, which accounts for non-response and unequal probability of selection due to stratification, was 75 percent.
In addition to the 131 participating original schools, 27 replacement schools also participated for a total of 158 participating schools. The weighted and unweighted school response rates with replacement schools were 92 percent.
All schools selected for PIRLS were also asked to participate in ePIRLS. Five of the 158 participating schools declined to also participate in ePIRLS. The unweighted school response rate for ePIRLS in the final sample with replacement schools was 89.0 percent and the weighted response rate was 89.1 percent.
A total of 4,706 students were selected to participate in PIRLS from the 158 participating schools. Some 4,427 students participated, corresponding to weighted and unweighted response rates of 94 percent. From the 153 schools that participated in ePIRLS, 4,105 students participated for weighted and unweighted response rates of 90 percent.
The school administrator at each participating school and the reading teacher for each selected classroom as asked to complete a questionnaire. Some 150 of the 158 administrators participated for a weighted and unweighted response rate of 95 percent. Of the 215 teachers asked to participate, 207 responded for a weighted and unweighted response rate of 96 percent.