The term "survey instrument" refers to: (1) the questionnaires, which serve as the primary source of data on a given respondent, and (2) documents such as the household record cards that collect information on members of the respondent's household. A unique set of survey instruments was used during each survey year to collect information from respondents. The primary variables found within the main data set of each NLS cohort were derived directly from one or more survey instruments (e.g., questionnaires, household interview cards, etc.).
The questionnaires are critical elements of the NLS documentation system and should be used by each researcher to find out the wording of questions, coding categories, and the universe of respondents asked to respond to a given question.
Certain other documents, namely Field Representative's Manuals and flowcharts, provide background information on how specific survey instruments were administered or offer the researcher additional tools for working with a questionnaire. While not actually survey instruments, these additional documents are described within this section.
Note that while the source of the majority of variables in the main NLS data sets was the questionnaire or one of the other survey instruments, certain NLS variables were created either from other NLS variables or from information found in an external data source.
There were separate and distinctly different questionnaires for each survey year. Each questionnaire is organized around a set of topical subjects, the titles of which usually appear on either the first page of each section of the questionnaire or as page headers.
Each questionnaire collected two general types of information: (1) information on the actual interview (e.g., interview dates, times, and contact methods) and (2) information supplied by the respondents on various topics related to their work and life experiences. Each survey instrument was organized around core sets of questions: current labor force status, retrospective work history, attitudes, health, marital history, household composition, assets, and income. In addition, the interview schedules contained special sets of questions on a variety of topics specific to the particular stage of life: child care and fertility questions were asked in the early survey years, while later surveys emphasized retirement and pension plans.
Information Sheet: Information Sheets (or flap items), located within the questionnaires, were usually designed in such a way that the interviewers could fold the sheet out to the side of the actual questionnaire and refer to the items on the flap during the interview. Various information items from previous interviews were clerically entered by Census and used by the interviewer during the survey. These included information such as name of previous employer, date of previous interview, and marital status and place of residence at the time of previous interview.
The interviewer also transcribed information recorded in the questionnaire during the current survey onto the Information Sheet. The only current survey year item that a user would need from the flap was "current marital status," transcribed from the Household Record Card in certain survey years. Items referenced frequently during the interview were more conveniently located when transferred to the flap.
Questionnaire Item or Question Number: The questionnaire item or question number is the generic term referring to the printed source of data for a given variable. A questionnaire item may be a question, a check item, or an interviewer's reference item that appears within one of the survey instruments. Each questionnaire item has been assigned a number or a combination of numbers and letters to help the user link each variable to its location in a survey instrument.
Different designations were used within the documentation system to identify varying types of questionnaire items, as depicted in Table 1. The question number appears to the right of each variable description within the codebook. Data file users can access variable titles and codebook information via the "Accessing Data by Question Number" function.
Table 1. Question Numbering Conventions
Check Item (CH)
CH J3; CH AA
Interviewer Reference Item:
Interviewer Reference (R)
In the vast majority of cases, the reference is to a specific question item found in the survey (e.g., 22F or 3B). The convention "CH" is used to identify interviewer check items that occur within the survey (e.g., CH B). Their purpose is to direct the interviewer to the next appropriate question. The convention "R" denotes a reference item (e.g., R2 or 12R). Typically, reference items are grouped in a section of the survey instrument called the Information Sheet, which contains information that interviewers frequently refer to during the course of an interview. Items designated "R" in the survey instruments are also designated "R" in the documentation. Finally, when an item does not include a question number, only the page number ("PG") of the questionnaire on which a particular item appears is identified (e.g., PG 1). The first page of most questionnaires contains unnumbered interview status information and transcribed Household Record Card information.
Household Record Cards
NLS questionnaires include the collection, during each interview, of information on the members of each respondent's household. In the PAPI years these data were collected primarily through the "Household Roster" section of the questionnaire, which in turn relies upon information provided by Census personnel and found on the separate Household Record Cards. Respondents were selected on the basis of a screening of sample households. Both the instruments used for the household data collection and the household screening instruments that were used to draw the samples of respondents are described below.
Household Screener & Household Record Cards: Prior to most PAPI interviews, Census interviewers completed or updated information found on a Household Record Card. Part of this information was transferred during the main interview to the "Household Roster" section of the questionnaire. The first Household Record Card (LGT-1, dated 2/23/1966) was the screening instrument used to select the Young Women respondents for interview. Information for this first card was gathered from any available household member, while respondents provided comparable information in subsequent surveys. Each Household Record Card (1) enumerates all persons currently living in the household; (2) records for each person: name, relationship to respondent, whether this person is considered a household member, marital status, birth date, and sex; (3) summarizes changes since the last survey in household composition; and (4) provides information on the respondent's current and/or permanent address and telephone number at the time of interview, as well as the names of people who will know how to contact the respondent at the time of the next interview.
Five versions of the paper Household Record Cards, each covering approximately three surveys, were used. While information from these cards does not, in general, appear as variables within any of the data files, certain information present on the cards detailing each respondent's current household composition is transferred to the Household Roster section of the questionnaires. In addition, certain demographic variables as of the initial survey year, notably age, birth date, race, and sex, were derived from the 1966 household screenings. Users can consult each survey's Field Representative's Manual for the specific instructions and definitions used to complete each card.
School Survey (Young Men)
A supplemental survey of the last secondary school attended by Young Men respondents (as well as NLS Young Women cohort) was conducted in 1968. This special survey was mailed to the designated high schools and was designed to collect academic performance information and intelligence scores for respondents, as well as information on the programs and facilities of each high school. The instrument was called the Survey of Work Experience of Young Men and Women School Survey.
Field Representative's Manual/Interviewer's Reference Manual
Each survey instrument that went into the field was accompanied by anor Field Representative's Manual, which provided Census interviewers with background information on the NLS, respondent location instructions, and detailed question-by-question instructions for coding and completing the questionnaire and Household Record Cards. Note that Field Representative's Manuals do not always include all the actual questions.
The questionnaires are lengthy and often present the researcher with the complex task of determining the universe of respondents asked a specific question. To assist in this task, flowcharts have been developed that graphically depict the skip patterns (the manner in which the different universes of respondents "flow" through the interview) for some questionnaires. Flowcharts are available for some post-1977 surveys as PDF files; comparable information for earlier questionnaires appears within the codebook under the heading "Universe Information."