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2011–12 SASS Methods and Procedures

Questionnaire Design

The 2011–12 SASS consisted of five types of questionnaires: a school district questionnaire, principal questionnaires, school questionnaires, teacher questionnaires, and a school library media center questionnaire. The principal, school, and teacher questionnaires were modified slightly between the public school versions (Principal Questionnaire, School Questionnaire, Public School Questionnaire (With District Items), and Teacher Questionnaire) and private school versions (Private School Principal Questionnaire, Private School Questionnaire, and Private School Teacher Questionnaire) to refer to either the public or private sector correctly. The Private School Questionnaire also incorporated the Private School Universe Survey (PSS) items that were collected at the same time as SASS in 2011–12. The School Library Media Center Questionnaire was administered to public (including public charter) schools in 2011–12.

Sampling Frames

The sampling frame for public schools was an adjusted version of the 2009–10 Common Core of Data (CCD), which reflects the population of public schools in the 2009–10 school year. CCD includes traditional public schools, public charter schools, DoD-operated domestic military base schools, and special purpose schools, such as special education, vocational, and alternative schools. Schools outside of the United States, schools that teach only prekindergarten, kindergarten, or postsecondary students, and Bureau of Indian Education-funded schools were deleted from the CCD frame prior to sampling for SASS. Public schools that closed in school year 2009–10 or were not yet opened were not included. Prior to stratification and sampling, CCD schools were collapsed to match the SASS definition of a school.

The sampling frame for private schools is based on a dual frame approach since the list frame does not provide complete coverage. The list frame was based on the 2009–10 PSS, updated with private school organization lists and state lists collected by the Census Bureau in the summer of 2010. An area frame was used to find schools missing from the list frame, thereby compensating for the incomplete coverage of the list frame. The area frame was also based on the 2009–10 PSS, but no updates were made.

The sampling frame for the teacher questionnaires consisted of lists of teachers provided by school districts or schools in the SASS sample. Teachers were defined as any staff who taught a regularly scheduled class to students in grades K–12 or comparable ungraded levels. Census Bureau staff requested the Teacher Listing Form (TLF) or an electronic list of teachers from districts or schools for all traditional public, public charter, and private schools in the SASS sample to obtain a complete list of all the teachers employed at each school. The form included space for schools to indicate the following: the teacher’s assignment (subject matter), full- or part-time status, and level of experience. The sample of teachers was selected from all of the sampled schools for which a Teacher Listing Form or an electronic list of teachers was collected.

All districts, principals, and library media centers from sampled schools were also surveyed for SASS.

Sample Design

In response to changing needs in education data (i.e., emerging need for more robust statistics for middle schools and high-poverty schools), the 2011–12 SASS introduced a revised stratification of public schools in the sample design. To improve the efficiency of the 2011–12 SASS sample design and ensure that the new as well as existing sampling goals as reflected in the revised stratification were met, the school and teacher sample allocations were optimized. While no stratification changes were made to the private school sample design, the private school and teacher sample allocations were optimized in conjunction with the public sector samples.

The following is a summary of the changes made to the public school sample design:

  • Four school levels (primary, middle, high, and combined) were used in the traditional public school stratification rather than three (elementary, secondary, and combined); three school levels continued to be used for stratifying public charter and private schools.
  • Eligibility for the National School Lunch Program, which is a proxy measure for school poverty, was added as a sorting variable for all public schools.
  • Career and Technology Centers (CTC) and schools with high American Indian (HAI) enrollment were not stratified separately from other public schools.
  • Bureau of Indian Education-funded (BIE) schools were excluded from the sampling frame.
  • Delaware was removed from the special district strata where all districts in these selected states had at least one school in sample.
  • Districts governing public charter schools sampled for SASS received the School District Questionnaire. In 2007–08, these districts only received a School District Questionnaire if a regular public school in the district also was in the SASS sample. All public charter schools still received the Public School Questionnaire (With District Items).
  • The following change was made to the teacher sample design:

    The Teacher Listing Form (TLF) item asking whether or not the teacher was expected to be teaching in the school the subsequent school year was removed from the TLF and thus was not used for selecting the teacher sample.

    Data Collection

    The 2011–12 SASS used a combination of mail-based methodology and Internet reporting for questionnaires, with telephone and in person field follow-up. An advance letter was mailed to sampled schools during the summer of 2010 to verify school addresses. Subsequently, a package containing all surveys and explanatory information was mailed to sampled schools. The Census telephone center called sampled schools to verify school information, establish a survey coordinator, and 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.

    Data Editing

    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.

    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 SASS had 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.

    Response Rates

    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.

    SASS Weighted unit and overall response rates using initial base weight, by survey: 2011–12
    Survey Unit response rate (percent)   Overall response rate (percent)
    Public School Teacher Listing Form 79.6  
    Private School Teacher Listing Form 71.6  
    Public School District 80.6  
    Public School 72.5  
    Private School 65.7  
    Public School Principal 72.7  
    Private School Principal 64.7  
    Public School Teacher 77.7   61.8
    Private School Teacher 69.9   50.1
    Public School Library Media Center 72.9  
    Not applicable.
    NOTE: Response rates were weighted using the inverse of the probability of selection (initial base weight).
    SOURCE: U.S. Department of Education, National Center for Education Statistics, Schools and Staffing Survey (SASS), “Public School and Private School Teacher Listing Forms; Public School District, Public School, Private School, Public School Principal, Private School Principal, Public School Teacher, Private School Teacher, and Public School Library Media Center Documentation Data Files,” 2011–12.

    Manuals and Technical Reports

    NCES 2013311: Characteristics of Public School Districts in the United States: Results From the 2011–12 Schools and Staffing Survey

    NCES 2013312: Characteristics of Public and Private Elementary and Secondary Schools in the United States: Results From the 2011–12 Schools and Staffing Survey

    NCES 2013315: Characteristics of Public Elementary and Secondary School Library Media Centers in the United States: Results From the 2011–12 Schools and Staffing Survey

    NCES 2013313: Characteristics of Public and Private Elementary and Secondary School Principals in the United States: Results From the 2011–12 Schools and Staffing Survey

    NCES 2013314: Characteristics of Public and Private Elementary and Secondary School Teachers in the United States: Results From the 2011–12 Schools and Staffing Survey

    NCES 2016817: Documentation for the 2011–12 Schools and Staffing Survey