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2017–18 NTPS Methods and Procedures
Read brief descriptions of the methods and procedures used for the 2017–18 NTPS. Please refer to the reports that accompany each data set for more complete information about the following categories: Questionnaire Design, Sampling Frames, Sample Design, Data Collection, Editing, Imputation, Weighting, Response Rates, and Manuals and Technical Reports.
The 2017–18 NTPS consisted of six questionnaires, three each for public and private schools. These were the Principal Questionnaire, School Questionnaire, Teacher Questionnaire, Private School Principal Questionnaire, Private School Questionnaire, and Private School Teacher Questionnaire. Whereas the 2015–16 NTPS included public schools only (both traditional and charter), the 2017–18 iteration collected data from both public and private schools. The principal, school, and teacher questionnaires were modified slightly between the public and private school versions 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 NTPS in 2017–18.
Questionnaires were designed to include both core modules (i.e., sections that will be asked every NTPS administration) and rotating modules (i.e., sections that will be asked in alternating NTPS administrations). The questionnaires can be found here: https://nces.ed.gov/surveys/ntps/question1718.asp.
Public Schools: The starting point for the 2017–18 NTPS public school sampling frame was the 2014–15 Common Core of Data (CCD) Nonfiscal School Universe data file. The sampling frame was adjusted from the CCD to fit the definition of a school eligible for NTPS. To be eligible for NTPS, a school was defined as an institution or part of an institution that provides instruction to students, has one or more teachers to provide instruction, serves students in one or more of grades 1–12 or the ungraded equivalent, and is located in one or more buildings apart from a private home. It was possible for two or more schools to share the same building; in that case, they were treated as different schools if they had different administrators (i.e., principal or school head). This definition is unchanged from the Schools and Staffing Survey (SASS).
The 2017–18 NTPS universe of schools is confined to the 50 states plus the District of Columbia and excludes the other jurisdictions, Department of Defense overseas schools, and CCD schools that do not offer teacher-provided classroom instruction in grades 1–12 or the ungraded equivalent. This last group includes schools that are essentially administrative units that may oversee entities that provide classroom instruction or may only provide funding and oversight. Although Bureau of Indian Education-funded (BIE) schools are eligible for NTPS, these schools were not oversampled and the data do not support separate BIE estimates.
Private schools: The 2017–18 NTPS private school frame was based on the 2015–16 Private School Universe Survey (PSS) list frame and certainty area frame. In order to provide coverage of private schools founded since 2016 and to improve coverage of private schools existing in 2016, the Census Bureau collected membership lists during the summer of 2016 from private school associations and religious denominations. The associations were asked to list all schools meeting the PSS school definition. The 50 states and the District of Columbia were also asked to provide lists of private schools meeting the PSS definition of a school. Schools on the private school association membership lists and the state lists were compared to the 2015–16 PSS list frame. Any school that did not match to the 2015–16 PSS list frame was added to the existing 2017–18 PSS list frame.
Principals: All principals from sampled schools were also surveyed for NTPS.
Teachers: The sampling frame for the teacher questionnaires consisted of lists of teachers who worked at schools selected for the NTPS sample. Teachers were defined as any staff who taught a regularly scheduled class to students in grades K–12 or comparable ungraded levels. Teacher Listing Forms (TLFs) were collected from sampled schools by mail or online, via clerical look-up, or through vendor purchase. Schools were asked to provide teachers' full- or part-time teaching status and their subject matter taught, and the sample of teachers was selected from all sampled schools for which a Teacher Listing Form was completed.
Public schools: The sample design for public schools was largely consistent between the 2015–16 NTPS design and the 2017–18 version, with some exceptions. Notably, the prior iteration was not designed to produce state-level estimates. In the 2017–18 cycle, both national and state-level estimates are supported for public schools, principals and teachers. For public schools, the sample was designed to produce national estimates for a wide range of topics by charter status, community type, school level, school size, and free and reduced-price lunch enrollment, as well as estimates by state.
Private schools: For private schools, which were not part of the prior iteration, the sample was designed to produce national estimates for a wide range of topics by school classification, community type, school level, and school size, as well as estimates by private school affiliation (Catholic, Baptist, Seventh Day Adventist, Lutheran, Jewish, other religious, nonsectarian regular, nonsectarian special education, and nonsectarian special emphasis).
In general, both the public and private school samples were drawn from their respective frames using a systematic probability proportionate to size (PPS) sample, where size is defined to be the square root of the number of full-time-equivalent (FTE) teachers in the school.
The 2017–18 NTPS 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 2017 to verify school addresses and eligibility. Subsequently, a package containing school and principal 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 types of schools expected to have a lower response propensity (e.g., city schools) and 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. Sampled principals 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, 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.
The NTPS used two main approaches to impute data. First, donor respondent methods, such as hot-deck imputation, were used. Second, if no suitable donor case could be matched, the few remaining items were imputed using mean or mode from groups of similar cases to impute a value to the item with missing data. Finally, in rare cases for which imputed values were inconsistent with existing questionnaire data or out of the range of acceptable values, Census Bureau analysts looked at the items and tried to determine an appropriate value.
Weighting of the sample units was carried out to produce both national and state-level estimates for public and private schools, principals, and teachers. The weighting procedures used in NTPS 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.
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 principals and schools, only one sampling stage was involved; therefore, for these components, the weighted overall response rate and the weighted response rate are the same. The weighted response rates for each component are shown below.
|Weighted unit and overall response rates using initial base weight, by survey: 2017–18|
|Survey||Unit response rate (percent)||Overall response rate (percent)|
|Public School Principal||70.2||†|
|Public School Teacher Listing Form||87.1||†|
|Public School Teacher||76.7||67.0|
|Private School Principal||62.6||†|
|Private School Teacher Listing Form||71.0||†|
|Private School Teacher||75.9||53.9|
|† 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, National Teacher and Principal Survey (NTPS), "Public and Private School, School Principal, and School Teacher Documentation Data Files," 2017–18.|