2020–21 NTPS Methods and Procedures

Read brief descriptions of the methods and procedures used for the 2020–21 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.

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Questionnaire Design

The 2020–21 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 and 2020–21 iterations 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 2020–21.

NTPS questionnaires undergo cognitive and usability testing to ensure that respondents understand questions as intended.

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/question2021.asp.

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Sampling Frames

Public Schools: The starting point for the 2020–21 NTPS public school sampling frame was the 2017–18 and 2018–19 Common Core of Data (CCD) Nonfiscal School Universe data files. 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 in one or more of grades 1–12 or the ungraded equivalent and has one or more teachers who provide instruction in one or more buildings apart from a private home or without a physical building. In addition, a public school receives public funds as primary support, and is operated by an education agency.

The 2020–21 NTPS universe of public schools was confined to the 50 states plus the District of Columbia and excluded the other jurisdictions, Department of Defense overseas schools, and CCD schools that did not offer teacher-provided classroom instruction in grades 1–12 or the ungraded equivalent. This last group included schools that were 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 2020–21 NTPS private school frame was based on the 2017–18 Private School Universe Survey (PSS) list frame and certainty area frame. In order to provide coverage of private schools founded after the PSS list frame was developed and to improve coverage and update frame information on existing private schools, the Census Bureau collected membership lists in early 2017 from private school associations and religious denominations. The associations were asked to list all schools meeting the PSS school definition. The Census Bureau also collected additional frame information (grade range, number of teachers, and number of students) during the refresh operation. To be eligible for NTPS, a school was defined as an institution or part of an institution that provides instruction to students in one or more of grades 1–12 or the ungraded equivalent and has one or more teachers who provide instruction in one or more buildings apart from a private home or without a physical building. In addition, a private school is not supported primarily by public funds. 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 2017–18 PSS list frame. Any school that did not match to the 2017–18 PSS list frame was added to the existing 2020–21 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. 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' subject matter taught, and the sample of teachers was selected from all sampled schools for which a Teacher Listing Form was completed.

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Sample Design

Public schools: The sample design for public schools was largely consistent between the 2017–18 NTPS design and the 2020–21 version. 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 poverty status, as well as estimates by state.

In total, about 9,900 public schools and their principals were sampled for the 2020–21 NTPS, along with about 68,300 teachers in those schools.

Private schools: The sample design for private schools was largely consistent between the 2017–18 NTPS design and the 2020–21 version. For private schools, 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.

In total, about 3,000 private schools and their principals were sampled for the 2020–21 NTPS, along with about 8,000 teachers in those schools.

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Data Collection

The 2020–21 NTPS used a combination of mail-based methodology and Internet reporting for questionnaires, with telephone, mail, and email follow-up. An advance letter was mailed to sampled schools during the summer of 2020 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. Telephone, email, and mail follow-up was conducted for types of schools expected to have a lower response propensity and schools that had not returned the TLF. Schools were called to remind the survey coordinator to have staff complete and return all forms. Sampled principals and teachers were called to attempt to complete the questionnaire with them over the phone. Telephone, email, and mail follow-up was conducted for schools and teachers that had not returned their questionnaires.

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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, 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.

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Imputation

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.

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Weighting

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 take into account both the school's selection probability and survey nonresponse. For more details about weighting procedures and nonresponse bias analysis, please see the First Look reports listed in the Manuals and Technical Reports section below.

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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 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: 2020–21
Survey		Unit response rate (percent)	Overall response rate (percent)
Public School Teacher Listing Form		88.2	†
Private School Teacher Listing Form		71.8	†
Public School Principal Questionnaire		68.0	†
Private School Principal Questionnaire		61.7	†
Public School Questionnaire		65.6	†
Private School Questionnaire		61.4	†
Public School Teacher Questionnaire		62.4	55.0
Private School Teacher Questionnaire		60.6	43.5
† 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," 2020–21.

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Manuals and Technical Reports

NCES 2022–111 Characteristics of 2020–21 Public and Private K-12 Schools in the United States: Results from the National Teacher and Principal Survey First Look

NCES 2022–112 Characteristics of 2020–21 Public and Private K–12 School Principals in the United States: Results from the National Teacher and Principal Survey First Look

NCES 2022–113 Characteristics of 2020–21 Public and Private K–12 School Teachers in the United States: Results from the National Teacher and Principal Survey First Look

Documentation for the 2020–21 National Teacher and Principal Survey (Forthcoming)