How the Samples of Schools and Students Are Selected for the Main Assessments (State and National)In state assessments (mathematics, reading, science, and writing), a sample of schools and students is selected to represent a participating state. In an average state, 2,500 students in approximately 100 public schools are assessed per grade, per subject assessed. The selection of schools uses stratified random sampling within classes of schools with similar characteristics. But some schools or groups of schools (districts) may be selected for each assessment cycle if they are unique in the state. For instance, a particular district may be in the only major metropolitan area of a state or have the majority of a minority population in the state. If a state decides not to participate at the state level, schools in that state identified for the national sample will still be asked to participate. For national results, national probability samples of schools and students are selected to represent the diverse student population in the United States. The numbers of schools and students vary from cycle to cycle, depending on the number of subjects and items assessed. A national sample has sufficient schools and students to yield data for public schools and for the four NAEP regions of the country, as well as sex, race, degree of urbanization of school location, parent education, and participation in the National School Lunch Program (NSLP). A separate grade 12 sample of schools is also selected to produce national and regional estimates, as state NAEP does not yet include grade 12 (a pilot study of grade 12 state NAEP will be held in 2009). A national sample of nonpublic (private) schools is also selected for grades 4, 8, and 12. This sample is designed to produce national and regional estimates of student performance. Typically, 30 students per subject per grade are selected randomly in each school. Some of the students who are randomly selected are classified as students with disabilities (SD) or as English language learners (ELL). NAEP's goal is to assess all students in the sample. For more information, read about NAEP's inclusion policy for a description of accommodation issues. To find out more about NAEP sampling methods, see details about sampling for the reading assessments, or see some of the most frequently asked questions about the state sample design. Note that beginning with the 2002 NAEP assessments, a combined sample of public schools was selected for both state and national NAEP. This was done in response to the NAEP redesign of 1998. It was thought that drawing a subset of schools from all of the state samples to produce national estimates would reduce the burden by decreasing the total number of schools participating in state and national NAEP. From this group of schools, representing 50 states, a sub-sample was identified as the national subset. Please note that the long-term trend assessments, scheduled for every four years, use a nationally representative sample and do not report results by state.)
|
