The 2007–08 administration of SASS consisted of five types of questionnaires: district questionnaires, principal questionnaires, school questionnaires, teacher questionnaires, and school library media center questionnaires. District surveys contained questions on student enrollment, staffing patterns, teacher recruitment, hiring practices, teacher dismissals, salary schedules, school choice, magnet programs, and graduation requirements. Principal surveys collected information about principal demographic characteristics, training, experience, salary, goals and decision making, judgments about the seriousness of school problems, and, new to 2007–08, instructional time, and teacher and school performance. Public and private school surveys obtained information such as grades offered, number of students enrolled, staffing patterns, teaching vacancies, high school graduation rates, programs and services offered, and college application rates. Teacher surveys were designed to measure teachers' education and training, teaching assignment, certification, workload, professional development, perceptions and attitudes about teaching, and income from school and non-school jobs. School library media center surveys were designed to obtain information about the amount and experience of library staff, and the organization, expenditures, and collections of the library media center.
The sampling frame for public traditional and charter schools was built from the 2005–06 Common Core of Data (CCD) school survey, which is a universe survey of all elementary and secondary schools in the United States. Prior to stratification and sampling, the CCD frame was modified extensively to meet the needs of SASS. For example, schools were added and deleted from the CCD in order to fit the definition of a school used in SASS. Schools operated by the Department of Defense or those that offered only kindergarten or prekindergarten or adult education were excluded from the SASS sample. The SASS sample is a stratified probability proportional to size (PSS) sample. All schools, except BIA-funded schools, undergo multiple levels of stratification.
A separate universe of schools operated or funded by the Bureau of Indian Affairs (BIA) in 2005–06 was drawn from the Program Education Directory maintained by the BIA. [CCD now defines BIA as its own "territory," similar to Puerto Rico and other non-50 state territories, and does not permit duplicates to be reported by the states]. All BIA schools meeting the SASS definition of a school were included in the sample.
The sampling frame for private schools employed a dual frame approach since the list frame does not provide complete coverage. The list frame was based on the 2005–06 Private School Universe Survey (PSS), updated with private school organizations and state lists collected by the Census Bureau in the summer of 2006. An area frame was used to find schools missing from the list frame, thereby compensating for the incomplete coverage of the list frame.
The sampling frame for the teacher questionnaires consisted of lists of teachers provided by sampled schools. The Teacher Listing Form (TLF) was collected as early as possible in the 2007–08 school year at all public (including public charter), private, and BIA-funded schools in the SASS sample to obtain a complete list of all the teachers employed at each school. The sample of teachers was selected from all of the schools that provided teacher lists.
The sample design for the school survey met the objectives for SASS and took into consideration the response burden for schools. The main design objective of the school survey was to provide estimates of school characteristics by the following key analytical domains: the nation; elementary and secondary levels for all sectors; public schools with a population of at least 25 percent American Indian or Alaska Native students; BIA schools at the national level; public schools by school level, region, and state; and private schools by school level, region, and affiliation strata.
Another objective was to balance the requirements of the samples in SASS. For each sampled school, all districts in the public sector, principals, and library media centers in the public and BIA-funded school sectors received questionnaires. The 2007–08 SASS sampled schools first, and then linked each school to its corresponding school district (or local education agency). To obtain a representative teacher sample, schools were more likely to be selected if there was a larger number of teachers within a given school, although schools of all sizes were sampled. Teachers within schools were then sampled at a rate of at least one and no more than 20 teachers per school, averaging between 3 and 8 teachers per school. The SASS sample design also sought to minimize selecting the same schools as other NCES school-based surveys.
The 2007–08 SASS returned to the methodology used in the 1999–2000 SASS, which was a mail-based survey, with telephone and field follow-up. An advance letter was mailed to sampled schools during the summer 2007 to verify school addresses. Subsequently, a package containing all surveys and explanatory information was mailed to sampled schools. Using a computer-assisted telephone-interviewing (CATI) instrument to verify school information, schools were contacted to establish a survey coordinator, and to follow up on the Teacher Listing Form (TLF), which served as the teacher list frame. Sampled teachers were mailed questionnaires on a flow basis. Field follow-up was conducted for schools that had not returned the TLF. Schools were called from Census telephone centers to remind the survey coordinator to have staff complete and return all forms. Individual survey respondents (e.g. principal, librarian, and teachers) were called from the telephone centers to attempt to complete the questionnaire with them over the phone. Field follow-up was conducted for schools and teachers that had not returned their questionnaires.
The U.S. Census Bureau conducted the data processing. Each questionnaire was coded according to its response status—for example, whether the questionnaire contained a completed interview, a respondent refused to complete it, a school district merged with another district, or a school closed. The next step was to make a preliminary determination of each case's interview status, i.e., whether it was an interview, a non-interview, or if the respondent was ineligible for the survey. Information from the CATI instrument was also used to determine the preliminary status of questionnaires, particularly to determine if the school or other respondent was eligible for the survey or not.
Once the data were compiled, a computer program conducted a series of quality control checks, such as range checks, consistency edits, and blanking edits, and generated a list of cases where problems occurred in each survey. After the completion of these checks, the program made a final determination of whether the case was eligible for the survey, and if so, whether there were sufficient data for the case to be classified as an interview. As a result, a final interview status recode value was assigned to each case.
SASS used four methods to impute values for questionnaire items that respondents did not answer. These were: (1) using data from other items on the questionnaire; (2) extracting data from a related component of SASS; (3) extracting data from the sampling frame (CCD or PSS); and (4) extracting data from the record of a sampled case with similar characteristics (commonly known as the "hot deck" method for imputing item response).
Weighting of the sample units was carried out to produce national, regional, and state estimates for public schools, districts, principals, teachers, and school libraries. Private schools, principals, and teachers were weighted to produce national, regional, and affiliation strata estimates. The weighting procedures used in the Schools and Staffing Survey have three purposes: to take into account the school's selection probability; to reduce biases that may result from unit nonresponse; and to make use of available information from external sources to improve the precision of sample estimates.
Weighted response rates are defined as the number of in-scope responding questionnaires divided by the number of in-scope sampled cases, using the base weight (inverse of the probability of selection) of the record. There are two sampling stages for teachers; first, the school-level collection of the Teacher Listing Form (TLF) from sampled schools, and then, sampling of teachers from the TLF. When both stages are multiplied together, the product is the overall weighted response rate. For all other components, only one sampling stage was involved; therefore, for these components, the weighted overall response rate and the weighted response rate are the same. All response rates are published in the forthcoming 2007–08 First Look release reports and in the 2007–08 Documentation for the Schools and Staffing Survey.
NCES will publish a forthcoming series of First Look release reports and the 2007–08 Documentation for the Schools and Staffing Survey soon after release of the survey data.
