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NLSW -Mature and Young Women

Types of Variables

Four types of variables are present in Young Women data files. The type of variable affects the title or variable description which names each variable and the physical placement of the variable within the codebook. Types of variables include:

  1. Direct raw responses from a questionnaire or other survey instrument.
  2. Edited variables constructed from raw data according to consistent and detailed sets of procedures (e.g., occupational codings, *KEY* variables, etc.).
  3. Constructed variables based on responses to more than one data item either cross-sectionally or longitudinally and edited for consistency where necessary (e.g., highest grade completed). Note: In general, the NLS does not impute missing values or perform internal consistency checks across waves. Data quality checks most often occur in the process of constructing cumulative and current status variables.
  4. Variables provided by the Census Bureau or another outside organization based on sources not directly available to the user (e.g., characteristics of respondents' geographical areas).

Variable documentation

Reference numbers

Every variable within the main NLS data set has been assigned an identifying number that determines its relative position within the data file and documentation system. Reference numbers, once assigned, remain constant through subsequent revisions of the files. Reference numbers are assigned sequentially, with variables from the first survey year having a lower reference number than those variables specific to the second year, and so forth. Occasionally, variables are created sometime after the year in which the data were actually collected. These variables are frequently given a reference number that reflects the year in which the actual data were gathered rather than the year the created variable was constructed. Tables 1 and 2 list reference numbers for each survey year since 1967 for the Mature Women cohort and 1968 for the Young Women cohort.

Important information: NLS assistance

Persons contacting NLS User Services should be prepared to discuss their question or problem in relationship to the reference number(s) of the variable(s) in question.

Table 1. Reference numbers by survey year: Mature Women
Survey Year Reference Numbers
1967 R00001.00-R00813.00
1968 R00833.01-R00868.00
1969 R00868.01-R01333.01
1971 R01334.00-R02047.00
1972 R02048.00-R02876.00
1974 R02878.00-R03067.00
1976 R03080.00-R03273.50
1977 R03280.00-R04540.00
1979 R04542.00-R04892.00
1981 R04900.00-R05267.00
1982 R05270.00-R06640.00
1984 R06650.00-R07192.00
1986 R07203.00-R07809.00
1987 R07820.00-R08863.00
1989 R08865.00-R10077.00
1992 R10080.00-R13027.00
1995 R16007.00-R34923.00
1997 R34950.00-R42503.00
1999 R42527.00-R54394.00
2001 R54400.00-R63276.00
2003 R65000.00-R90510.00
Table 2. Reference numbers by survey year: Young Women
Survey Year Reference Numbers
1968 R00001.00-R00811.0
1969 R00851.00-R01405.00
1970 R01451.00-R02312.01
1971 R02518.00-R03323.13
1972 R03331.00-R04149.55
1973 R04150.00-R05100.00
1975 R05175.00-R05451.00
1977 R05467.00-R05857.00
1978 R05860.00-R07052.00
1980 R07061.00-R07547.00
1982 R07550.00-R08018.00
1983 R08019.00-R09452.00
1985 R09461.00-R10609.00
1987 R10616.00-R11069.00
1988 R11080.00-R12313.00
1991 R12315.00-R13629.00
1993 R13640.00-R15804.00
1995 R16007.00-R34923.00
1997 R34950.00-R42503.00
1999 R42527.00-R54394.00
2001 R54400.00-R63391.00
2003 R65000.00-R90510.00

Variable titles

Every variable within NLS main file data sets has been assigned a summary title that serves as the verbal representation of that variable throughout the hard copy and electronic documentation system. Variable titles are assigned by CHRR archivists who endeavor, within the limitations described below, to capture the core content of each variable and to incorporate within the title (1) common words that facilitate easy identification of comparable variables; (2) UNIVERSE IDENTIFIERS that specify the subset of respondents for which each variable is relevant; and (3) for some variables, REFERENCE PERIODS that indicate the period of time (e.g., survey year or calendar year) to which these data refer. Universe identifiers and reference periods are discussed below.

Universe identifiers

If two ostensibly identical variables differ only in that they refer to different universes, the variable title will include a reference to the applicable universe.

Example 1:

Mature Women:
'Reason for Being OLF, 77 (Not Empld, Have Worked)'
'Reason for Being OLF, 77 (Not Empld, Not Worked)'

Young Women:
'Rate of Pay Required To Accept a Job (Unemployed 68)'
'Rate of Pay Required To Accept a Job (OLF 68)'

Reference periods

Variable descriptions may include a phrase indicating the time period to which these data refer. The following general conventions apply:

Survey Year: When the variable title includes either the phrase XX INT (83 INT) or the year (e.g., 68) without the year being preceded by the preposition "IN," this indicates the survey year in which that variable was measured, not necessarily the year to which it applies.

Example 2:

Mature Women: 'Move to Current Residence -- Prior SMSA, 82 INT' refers to a residential move occurring in the period before the 1982 interview.

Young Women: 'Move to Current Residence - Prior Region, 83 INT' refers to a residential move described during the 1983 interview.

Example 3:

Mature Women: '# of Weeks Worked in Past Year, 67 *KEY*' refers to the weeks worked in the 12-month period preceding the 1967 survey.

Young Women: '# of Weeks Worked in Past Year, 68 *KEY*' refers to the weeks worked in the 12-month period preceding the 1968 survey.

Calendar Year: When a date follows a verbal description of a variable and is part of the prepositional phrase "in XX," the date identifies the calendar year for which the relevant information was collected. The Mature Women title in Example 4 refers to payments received in calendar year 1988 with data collected during the 1989 survey. The Young Women title in Example 4 refers to occupation in 1968, with the data collected in the 1969 survey.

Example 4:

Mature Women: 'Income from Social Security Payments Based on R Work Record in 88? 89.'

Young Women: 'Household Record - Family Member #1: Occupation in 68 (Age 14+) 69.'

Note that survey staff began using 4-digit years in question titles in 1995.

Important information: Variable searches

Searches for NLS variables are essentially searches for variable descriptions or titles. Electronic searches of NLS variables via NLS Investigator ultimately produce listings of variables by their reference number and variable description or title.

Flexibility in variable title assignment for raw data items is restricted by (1) the actual wording of the question as it appears within the survey instrument; (2) precedent, i.e., how that type of variable has been titled in previous survey years; and (3) in early survey years, a shorter allowable length for variable titles. An attempt is also made to include key phrases in variable titles so that large groups of variables with similar or related subject matter can be easily identified.

Users should be careful not to assume that two variables with the same or similar titles necessarily have the same (1) universe of respondents or (2) coding categories or (3) time reference period. While the universe identifier and reference period conventions discussed above have been utilized, users are urged to consult the questionnaires for skip patterns and exact time periods for a given variable and to factor in the relevant fielding period(s).

Variables with similar content (e.g., information on respondents' labor force status) may have completely different titles, depending on the type of variable (raw versus created).

Example 5: 'Employment Status Recode' (ESR) is the created or reconstructed version of the 'Activity Most of Survey Week' raw variable. The 'Activity' variable is derived from the first item of the full series of questions used by the Department of Labor (DOL) to obtain employment status; the title reflects questionnaire content. ESR, on the other hand, reflects the procedure used to recode the 'Activity' variable. This produces a constructed variable for all NLS respondents based upon responses to the 'Activity' question and all other questions used by the DOL to obtain employment status. These other questions serve to qualify and refine employment status beyond the answer to the initial 'Activity' question. (Note that ESR has been replaced by a similar variable, MLR, beginning in 1995; see the Labor Force Status section for details.)

Finally, different archivists over a period of three decades have performed the task of assigning variable descriptions to data from the NLS cohorts. While every effort has been made to maintain consistency, users may find some differences in variable titles. Two primary sources of variation exist in Original Cohort variable title assignment. The first is systematic error in which identical questions may have the same question wording across the four Original Cohorts but slightly different variable titles. The rule before 1995 was to make title consistency within a cohort of highest priority. Starting in 1995, joint fielding forced the archivist to choose one title and cross-reference the other cohort's title in the archivist notes. For this and other technical reasons associated with the switch from PAPI (paper and pencil interviews) to CAPI (computer-assisted personal interviews), the same questions from PAPI and CAPI years may not have identical titles; notes have been added to some codeblocks to assist users in finding these common questions. The second variation is attributed to random error due to spacing or punctuation errors. The sorting process that produces variable title listings usually places these variables near if not next to the series of interest.

How mode of interview affects question documentation

There are important differences between the content of telephone and personal interviews. In the late 1960s and early 1970s, most of the interviews were conducted in person, usually at the respondent's home. There was one attempt at a mail survey for the Older Men and Mature Women cohorts in 1968; however, the low response rate led to dropping that type of contact. After the first five years, the decision was made to conduct a major survey every five years and two telephone surveys during the five-year span so that problems of recall could be avoided and contact could be maintained with the respondents.

Differences in what appear to be comparable variables reflect variations in the wording of the question or the fact that the reference period for an identically worded question may be different in a personal versus a telephone interview. Questions that refer to the last five years were usually found in a personal (or five-year) interview. This difference means that some questions were only asked in the five-year surveys and some were asked only in the telephone surveys. Users conducting longitudinal analysis need to change their variable creation procedures to account for the differences in data collection between the early years of uninterrupted personal interviews and subsequent survey years when telephone interviews were used.

Survey Instruments

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.

Questionnaires

There are 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.

With the advent of CAPI (computer-assisted personal interviews) in 1995, Information Sheet items were inserted directly into the appropriate questions by the computer. During the interview, the computer prompted the interviewer with, for example, the name of an employer inserted as part of the question. The hard copy flap is therefore no longer used.

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.

Four different designations were used within the documentation system to identify varying types of questionnaire items in PAPI (paper and pencil interview) years (Mature Women 1967-92, Young Women 1968-93), 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 in PAPI surveys
Question: Question Number 112E; 59E
Interview Check: Check Item (CH) CH J3; CH AA
Interviewer Reference Item: Interviewer Reference (R) 123R; R4
Unnumbered Questions: Page Number PG1
Created Variables: CV CV

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.

Beginning with the first CAPI survey in 1995, questions were numbered using a different system. In general, questions asked of respondents during the interview begin with a three-letter code indicating the section of the questionnaire where the question falls. This letter code is followed by one or more numbers and letters indicating the placement of the question within that section. For example, HEA-11, a question on cigarette use, is followed by HEA-12A through HEA-12D, four questions on alcohol use. Questions that are part of a loop--that are asked about each different employer, for example--contain the additional letter group "ARR."Check items begin with "CK" followed by the three-letter code for that questionnaire section and a single letter (or letter and number) indicating the order in which the check was performed during the interview--for example, CK-HEA-A precedes CK-HEA-B. Table 2 lists the questionnaire sections and the corresponding codes. There are a few questions and check items within each section that may not follow this general pattern and may not appear in alphabetical or numerical order; users will be able to identify these questions by looking at the numbers assigned in the PDF or HTML questionnaire.

Table 2. Questionnaire sections and sample question numbers in CAPI surveys

Section

Abbreviation

Question Number Check Item
Introduction and Household Record

HRC

HRC-3A, HRC-15  
Respondent's Work History (CPS)

RWH

RWH-20, RWH-22B CK-RWH-A, CK-RWH-K2
Respondent's On Jobs Supplement

OJS

OJS-1-ARR, OJS-5C-ARR CK-OJS-E-ARR
Respondent's Employer Sort

RES

RES-1-ARR-01, RES-3B CK-ES-C
Respondent's Employer Supplement

RSP

RSP-38-ARR, RSP-148B-ARR CK-RSP-H-ARR
Respondent's Gaps in Employment

GAP

GAP-2-ARR, GAP-1B CK-GAP-B-ARR
Husband's/Partner's Work History (CPS)

HWH

HWH-1, HWH-27A CK-HWH-C, CK-HWH-L3
Husband's/Partner's On Jobs Supplement

HOJ

HOJ-3-ARR, HOJ-7 CK-HOJ-B, CK-HOJ-F-ARR
Husband's/Partner's Employer Sort

HES

HES-2-ARR, HES-3B CK-HES-C
Husband's/Partner's Employer Supplement

HSP

HSP-34A-ARR, HSP-53-ARR CK-HSP-G-ARR
Husband's/Partner's Gaps in Employment

HGP

HGP-1-ARR CK-HGP-A
Health

HEA

HEA-2, HEA-19C CK-HEA-H
Income

INC

INC-19E, INC-21 CK-INC-C
Other Family Background

OFB

OFB-8, OFB-20F-ARR CK-OFB-P
Education and Training

EAT

EAT-29 CK-EAT-E
Parents and Transfers (1997 and 2001)

PAR

PAR-12 CK-PAR-C
Interfamily Transfers (1999)

IFT

IFT-1B, IFT-36-ARR IFT_CK_L
Mobility

MOB

MOB-4, MOB-5B  
Attitudes and Contact Persons

ACP

ACP-4E, ACP-5  
Interviewer Remarks

ASG

ASG-8, ASG-10A  

Most question numbers remained constant across CAPI surveys, so users can easily find the same question in different survey years. However, the order in which the questions are asked may vary for a number of reasons. Therefore, questions may appear in the CAPI questionnaire out of numerical order. Users should be able to locate them by following the skip pattern information provided in both the printed questionnaire and the codebook, or by using the reference numbers, which are assigned in numerical order.

In PAPI interviews, the question number for created variables is simply "CV." In CAPI surveys, however, created variables are identified using assigned question numbers similar to those included in the questionnaire. Each created variable is given a question number that indicates the content of the variable. For example, the constructed hourly rate of pay variables are assigned the question numbers HROP-ARR-01 through HROP-ARR-07, indicating the rates for jobs one through seven. Created variables in CAPI survey years usually include the letters CV in the question name; in addition, all variables that have the word *KEY* in their title have been created.

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 relied 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. Starting with the 1995 survey, the information traditionally collected in the Household Record Cards became a part of the CAPI survey instrument.

Household screener and 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 Mature Women and 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, have been 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 Women)

A supplemental survey of the last secondary school attended by respondents within the Young Women and Young Men cohorts 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 an Interviewer's or 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.

Flowcharts

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." Starting with the 1995 computer-assisted surveys, skip patterns are part of the codebook documentation. Survey staff have also added some skip pattern information to pre-CAPI codebook pages as time permits.

Retention and Reasons for Non-Interview

Important information: Using 'Reason for Noninterview' variables

Researchers can use the 'Reason for Noninterview' variables to identify respondents who were dropped from the eligible sample. Respondents with a code of 12 were dropped due to missing two consecutive interviews for reasons other than death or refusal. It is more challenging to identify which respondents were dropped due to refusing an interview in 1981 (Mature Women), 1982 (Young Women), or earlier, as they share the same code as those who refused interviews in later years. To identify these respondents, researchers must examine the 'Reason for Noninterview' variables. Note that, because respondents are asked to report activities since the date of the last interview, most information from missed interviews was retrieved if the respondent was subsequently interviewed.

Eligible Mature Women sample and reasons for non-interview

In general, respondents selected for interviewing each year were those who participated in the initial survey and who were alive, residing within the United States at the interview date, and noninstitutionalized. (Exception: In 2003, interviews were conducted with a few institutionalized respondents. See R65097.00-R65124.00.) If a respondent had joined the Armed Forces, she would also have been excluded from interview during her enlistment, but no Mature Women respondents were members of the military during the survey period. However, the criteria used to select the eligible sample--respondents whom the Census Bureau attempts to interview in a given round--have varied somewhat over the years.

Beginning in 1968, any respondent who had refused to be interviewed during a previous round was dropped from the eligible sample. Beginning in 1971, respondents were also dropped from the eligible sample if they had not been interviewed in two consecutive surveys for reasons other than death or refusal (for example, respondents who could not be located or contacted during the field period--those with 'Reason for Noninterview' codes of 1, 2, 3, 4, 5, 6, 8, or 11). In 1982, Census ceased dropping individuals for these two reasons but did not attempt to reinterview those already dropped. For example, a respondent who missed the 1979 and 1981 interviews, or any two consecutive interviews prior to that year, for a reason other than death or refusal was not eligible to participate in 1982 or any subsequent year. Similarly, a respondent who refused to participate in 1981 or any earlier survey was not eligible in 1982 or any later survey. However, respondents who refused to participate or missed their second consecutive interview in 1982 were retained in the sample and were eligible for all subsequent interviews, unless they died, were institutionalized, or obtained a Congressional refusal.

Table MW1 depicts reasons for exclusion from the eligible sample and the years each applied.

Table MW1. Reasons for exclusion from the eligible sample: Mature Women

Out-of-Scope Reason

Years Exclusion Reason in Effect

Institutionalized All years. Exception: in 2003, interviewers made attempts
to interview respondents in institutions.
In the Armed Forces All years
Residing outside the U.S. All years
Deceased All years
Refusal during any one previous interview 1967-82. If interviewed in 1984, a respondent remained in
the eligible sample for subsequent interviews.
Dropped due to two consecutive noninterviews
for reasons other than refusal, death, or
membership in the Armed Forces
1971-82. If interviewed in 1984, a respondent remained
in the eligible sample for subsequent interviews.
Congressional Refusal Note MW1.1 1984-present

Note MW1.1: Congressional Refusal refers to a congressional representative requesting a respondent not be contacted again for the NLS after a respondent has completed one or more survey rounds.

Each survey year, NLS staff created a cumulative 'Reason for Noninterview' variable for the full sample of respondents. This created variable is a combination of (1) the noninterview reasons provided by Census for the subset of respondents designated as eligible for interview in that survey year and (2) the reason for noninterview assigned during a previous survey to out-of-scope respondents. For several surveys, CHRR released an additional variable reflecting the reasons for noninterview for only those respondents with whom interviews were attempted that year. This type of variable is available in 1974 (R07755.00) and in 1992 (e.g., R10093.00). The number of respondents that Census designated as eligible for interviewing fluctuated by survey year. The eligible sample can be identified by adding together the interviewed respondents and the respondents with a noninterview code in the original 'Reason for Noninterview' variables, those not marked 'Revised Deceased.'

Through the survey years there was concern that the number of respondents marked 'deceased' might be underreported and that some of the other 'Reason for Noninterview' categories might thus be overreported. In 2003, the Census Bureau, through the cooperation of the Social Security Administration, obtained SSA records for respondents who had shared their Social Security number with Census to verify whether respondents were living or deceased. As was previously suspected, a comparison of the SSA data with the survey data shows a substantially higher number of deceased respondents than was initially recorded. To correct for past survey discrepancies, a revised 'Reason for Noninterview--Revised/Deceased' variable using the SSA data was created for each survey year from 1970 on.

These revised variables are:

  • R01338.20
  • R02053.30
  • R02883.30
  • R03084.30
  • R03295.30
  • R04565.30
  • R04912.30
  • R05284.30
  • R06664.40
  • R07215.40
  • R07833.40
  • R08878.40
  • R10093.40
  • R16014.20
  • R34985.20
  • R42671.20
  • R63203.30
  • R76154.00.

Researchers are urged to use these updated variables rather than the original 'Reason for Noninterview' variables.

Instructions to interviewers on how to code a respondent's reason for noninterview appear within the Interviewer's Reference Manuals (or Field Representative's Manuals). The set of noninterview coding categories present during the initial survey years has been supplemented over the years with additional reasons for noninterview, and the meanings of existing categories have been refined. Table MW2 presents the raw coding categories present on the public data files and specifies the survey years during which each category was utilized.

Table MW2. Conceptual and raw coding categories for the 'Reason for Noninterview' variables: Mature Women
Conceptual Category Raw Coding Category
Note MW2.1

Code

Survey Years

CAN'T LOCATE Unable to locate [contact] R - reason not specified

[1]

All (1967-2003)

[Unable to locate R] - mover - no good address

[4]

All

INTERVIEW IMPOSSIBLE [Unable to locate R] - mover - good address given but interview impossible to obtain (e.g., "moved to Germany" or "lives too far from PSU - distance too great") Note MW2.2

[2]

All

[Unable to locate R] - mover - good address given but unable to obtain interview after repeated attempts, etc.

[3]

All

[Unable to locate R] - nonmover - unable to obtain interview after repeated attempts, etc.

[5]

All

Temporarily absent

[6]

All

Other

[11]

All

REFUSAL Refusal

[9]

All

Congressional refusal Note MW2.3

[14]

1984-2003

OUT OF SCOPE In Armed Forces

[7]

All

Institutionalized

[8]

All
Note MW2.4

Moved outside U.S. (other than Armed Forces)

[13]

1979-2003

DECEASED Deceased

[10]

All

DROPPED Non-interview for two years, R dropped from sample

[12]

1971-2003

Note MW2.1: Specific instructions to Census interviewers on use of these coding categories can be found in the cohort-specific Interviewer's Reference Manuals.

Note MW2.2: Beginning in the 1979 survey year, the separate "moved outside the U.S." coding category was added as a reason for noninterview and the "unable to locate" coding category no longer included those respondents who had moved outside the United States.

Note MW2.3: Congressional refusal refers to a congressional representative requesting a respondent not be contacted again for the NLS after a respondent has completed one or more survey rounds.

Note MW2.4: In 2003, interviewers sought out respondents in retirement communities, assisted living situations, and nursing homes.

The reason for noninterview coding categories depicted in Table MW3 below were constructed from the raw coding categories as shown in Table MW2. For example, the conceptual category "can't locate" is the sum of codes "1" and "4." Table MW3 depicts the count of non-interviewed by reason and survey year.

Table MW3. 'Reason for Noninterview': Mature Women 1968-2003
Survey Year Total Interviewed Total Not Interviewed Can't Locate Interview Impossible Refusal Out of Scope
Note MW3.1
Deceased Dropped
Note MW3.2
1968 4910 173 49 25 76 1 22 --
1969 4712 371 50 69 210 7 35 --
1971 4575 508 56 65 294 6 58 29
1972 4471 612 39 49 390 2 71 61
1974 4322 761 41 31 481 5 100 103
1976 4172 911 34 40 581 7 131 118
1977 3964 1119 22 49 762 6 141 139
1979 3812 1271 21 27 866 11 183 163
1981 3677 1406 18 17 953 9 232 177
1982 3542 1541 14 26 1048 8 261 184
1984 3422 1661 30 25 1092 13 317 184
1986 3335 1748 37 35 1093 10 395 178
1987 3241 1842 30 45 1153 14 422 178
1989 3094 1989 29 49 1211 21 504 175
1992 2953 2130 60 18 1206 24 652 170
1995 2711 2372 68 89 1208 33 811 163
1997 2608 2475 94 49 1148 38 986 160
1999 2467 2616 78 67 1135 48 1131 157
2001 2318 2765 61 85 1078 55 1334 152
2003 2237 2846 36 47 1066 65 1485 147

Note: This table is based on R00856.00, R00884.00, R01338.20, R02053.30, R02883.30, R03084.30, R03295.30, R04565.30, R04912.30, R05284.30, R06664.40, R07215.40, R07833.40, R08878.40, R10093.40, R16014.20, R34985.20, R42671.20, R63203.30, and R76154.00

Note MW3.1: Beginning with the 1979 survey, "moved outside the U.S." became a separate out-of-scope coding category. Respondents who could not be interviewed during the 1968-77 surveys because their residence-either within or outside of the U.S.-was too far away were coded within the "interview impossible" category. Out-of-scope counts for pre-1979 survey years thus may be understated.

Note MW3.2: Respondents who had been noninterviews for two consecutive survey years due to reasons other than refusal or death were eliminated from the eligible sample beginning with the 1971 interview. After the 1982 interview, no additional respondents were dropped based on this rule. The number of respondents in this category has decreased steadily after 1982 due to the death rate of the respondents.

Mature Women sample representativeness and attrition

The retention rate for the Mature Women at the final interview was 44.0 percent, or 2,237 of the original 5,083 respondents. Retention rate is defined as the percent of base-year respondents who were interviewed in any given survey year; included in the calculations are deceased and other out-of-scope respondents. An analysis of selected characteristics of respondents interviewed in the tenth year samples of the Original Cohorts found that noninterviews had not seriously distorted the sample representativeness of any of the cohorts for the characteristics studied (Rhoton 1984). A second analysis of differential attrition among wealthy and non-wealthy subsamples of each of the four Original Cohorts found that non-wealthy respondents of each cohort showed a consistent tendency toward greater attrition (Rhoton and Nagi 1991). Among the three younger cohorts, almost all of the difference between wealthy and non-wealthy subsamples is accounted for by attrition reasons other than the death of the respondent. In a more recent analysis, Zagorsky and Rhoton (1998) concluded that respondents with lower socio-economic status attrited at a higher rate than those with higher income and educational attainment. Further, the authors found that white respondents were more likely to remain in the survey than blacks and those of other races.

In Table MW4, the percentage of sampled respondents of each race is presented for the base survey year (1967) and the last interview year for which data is available. This table also provides information on numbers of deceased respondents by race.

Table MW4. Sample characteristics by race: Mature Women 1967 and 2003
Race
Note MW4.1
# of Interviewed Respondents Retention,
2003 as % of 1967
Number of Deaths
as of 2003
Note MW4.2
1967 2003
Non-black 3693 (72.7 %) 1693 (75.7%) 45.8% 950
Black 1390 (27.3 %) 544 (24.3%) 39.1% 535

Note MW4.1: See section on Race, Ethnicity & Nationality for details on race classifications. Respondent totals in this table are based on R00023.00.

Note MW4.2: Numbers are derived from R76154.00, a revised created variable that reflects mortality counts based on Social Security Administration records.

Eligible Young Women sample and reasons for non-interview

In general, respondents selected for interviewing each year were those who participated in the initial survey and who were alive, residing within the United States at the interview date, not members of the Armed Forces, and noninstitutionalized. (Exception: In 2003, an interview was conducted with an institutionalized respondent. See R65097.00-R65124.00.). However, the criteria used to select the eligible sample--respondents whom the Census Bureau attempts to interview in a given round--have varied somewhat over the years.

Beginning in 1969, any respondent who had refused to be interviewed during a previous round was dropped from the eligible sample. Beginning in 1971, respondents were also dropped from the eligible sample if they had not been interviewed in two consecutive surveys for reasons other than death or refusal (for example, respondents who could not be located or contacted during the field period--those with 'Reason for Noninterview' codes of 1, 2, 3, 4, 5, 6, 8, or 11). In 1983, the Census Bureau ceased dropping individuals for these two reasons, and in 1985 attempts were made to reinterview some of the dropped individuals. The following selection criteria determined which respondents would be reinterviewed (see Table YW1 for examples of each case):

  1. If the respondent refused to be interviewed in 1972 or earlier, she was not eligible to be reinterviewed. See example respondent 1.
  2. If the respondent missed her second consecutive survey in 1972 or earlier, she was not eligible to be reinterviewed. See example respondent 2.
  3. If the respondent refused an interview in 1973 or later, survey staff attempted to reinterview her in 1985. If the respondent was interviewed in 1985, she rejoined the eligible sample for all subsequent surveys. If she was not interviewed in 1985, she remained ineligible for all subsequent surveys. See example respondent 3.
  4. If the respondent was interviewed in 1971 and subsequently dropped due to two consecutive noninterviews, she was eligible for reinterview in 1985. If the respondent was interviewed in 1985, she rejoined the eligible sample for all subsequent surveys. If she was not interviewed in 1985, she remained ineligible for all subsequent surveys. See example respondent 4.
  5. If the respondent first refused to participate in 1982, she was not eligible to participate in 1983 but rejoined the eligible sample in 1985. She remained in the eligible sample regardless of her interview status in 1985. See example respondent 5 in the table.
  6. If the respondent was not interviewed in 1981 and 1982 for reasons other than death or refusal, she was never dropped from the sample. She remained eligible for all subsequent rounds regardless of prior participation. See example respondent 6.
Table YW1. Selection of respondents eligible for 1985 survey: Young Women
Example respondent Status 1972 or previous Status 1973-82 Status 1983 Status 1985 Status 1986 and subsequent

1

Refused any 1 survey (rni=9)
Note YW1.1
Not eligible (rni=9) Not eligible (rni=9) Not eligible (rni=9) Not eligible (rni=9)

2

Missed 2 consec. surveys (rni=1, 2, 3, 4, 5, 6, 8, 11) Not eligible (rni=12) Not eligible (rni=12) Not eligible (rni=12) Not eligible (rni=12)

3

Had not refused or missed 2 consec. surveys Eligible until refused, then not eligible (rni=9) Eligible until refused, then not eligible (rni=9) Eligible; if not interviewed, then rni=applicable code Eligible if interviewed in 1985
Not eligible if not interviewed in 1985, rni=9

4

Had not refused or missed 2 consec. surveys Eligible until missed 2 consec. surveys, then not eligible (rni=12) Eligible until missed 2 consec. surveys, then not eligible (rni=12) Eligible; if not interviewed, then rni=applicable code Eligible if interviewed in 1985
Not eligible if not interviewed in 1985, rni=12

5

Had not refused or missed 2 consec. surveys Refused for first time in 1982 Not eligible (rni=9) Eligible; if not interviewed, then rni=applicable code Eligible regardless of participation in 1985; if not interviewed, then rni=applicable code

6

Had not refused or missed 2 consec. surveys Missed 2nd consec. survey in 1982 Eligible (never dropped) Eligible regardless of prior participation Eligible regardless of prior participation

Note YW1.1: The reason for noninterview (RNI) codes are defined in Table YW3 below.

Table YW2 depicts reasons for exclusion from the eligible sample and the years each applied.

Table YW2. Reasons for exclusion from the eligible samples: Young Women

Out-of-Scope Reason

Years Exclusion Reason in Effect

Institutionalized All years. Note: in 2003 interviewers made attempts to interview respondents in institutions.
In the Armed Forces All years
Residing outside the U.S. All years
Deceased All years
Refusal during any one previous interview 1968-83. Some respondents rejoined the eligible sample in 1985.
Dropped due to two consecutive noninterviews for reasons
other than refusal, death, or membership in the Armed Forces
1971-83. Some respondents rejoined the eligible sample in 1985.
Congressional Refusal Note YW2.1 1985-present

Note YW2.1: Congressional Refusal refers to a congressional representative requesting a respondent not be contacted again for the NLS after a respondent has completed one or more survey rounds.

Each survey year, CHRR has created a cumulative 'Reason for Noninterview' variable for the full sample of respondents. This created variable is a combination of (1) the noninterview reasons provided by Census for the subset of respondents designated as eligible for interview in that survey year and (2) the reason for noninterview assigned during a previous survey to out-of-scope respondents. In 1982, CHRR began releasing an additional variable reflecting the reasons for noninterview for only those respondents with whom interviews were attempted that year (e.g., R07564.00). The number of respondents that Census designated as eligible for interviewing fluctuated by survey year. The eligible sample can be identified by adding together the interviewed respondents and the respondents with a noninterview code in the original 'Reason for Noninterview' variables, those not marked 'Revised Deceased.'

There was concern throughout the survey years that the number of respondents marked 'deceased' might be underreported and that some of the other 'Reason for Noninterview' categories might thus be overreported. In 2003, the Census Bureau, through the cooperation of the Social Security Administration, obtained SSA records for respondents who had shared their Social Security number with Census to verify whether or not respondents were living or deceased. As was previously suspected, a comparison of the SSA data with the survey data shows a substantially higher number of deceased respondents in the more recent surveys. To correct for past survey discrepancies, a revised 'Reason for Noninterview--Revised/Deceased' variable using the SSA data was created for each survey year from 1970 on.

These revised variables are:

  • R01453.20
  • R02525.20
  • R03353.20
  • R04171.20
  • R05195.20
  • R05483.20
  • R05874.30
  • R07099.30
  • R07564.70
  • R08032.70
  • R09473.40
  • R10628.40
  • R11092.40
  • R12327.40
  • R13652.40
  • R16014.20
  • R34985.20
  • R42671.20
  • R63203.30
  • R76154.00

Researchers are urged to use these updated variables rather than the original 'Reason for Noninterview' variables.

Instructions to interviewers on how to code a respondent's reason for noninterview appear within the Interviewer's Reference Manuals (or Field Representative's Manuals). The set of noninterview coding categories present during the initial survey years has been supplemented over the years with additional reasons for noninterview, and the meanings of existing categories have been refined. Table YW3 presents the raw coding categories present on the public data files and specifies the survey years during which each category was utilized.

Table YW3. Conceptual and raw coding categories for the 'Reason for Noninterview' variables: Young Women
Conceptual Category Raw Coding Category
Note YW3.1
Code Survey Years
CAN'T LOCATE Unable to locate [contact] R - reason not specified

[1]

All (1968-2003)

[Unable to locate R] - mover - no good address

[4]

All

INTERVIEW IMPOSSIBLE [Unable to locate R] - mover - good address given but interview impossible to obtain (e.g., "moved to Germany" or "lives too far from PSU - distance too great")
Note YW3.2

[2]

All

[Unable to locate R] - mover - good address given but unable to obtain interview after repeated attempts, etc.

[3]

All

[Unable to locate R] - nonmover - unable to obtain interview after repeated attempts, etc.

[5]

All

Temporarily absent

[6]

All

Other

[11]

All

REFUSAL Refusal

[9]

All

Congressional refusal
Note YW3.3

[14]

1985-2003

OUT OF SCOPE In Armed Forces

[7]

All

Institutionalized

[8]

All
Note YW3.4

Moved outside U.S. (other than Armed Forces)

[13]

1978-2003

DECEASED Deceased

[10]

All

DROPPED Non-interview for two years, R dropped from sample

[12]

1971-2003

Note YW3.1: Specific instructions to Census interviewers on use of these coding categories can be found in the cohort-specific Interviewer's Reference Manuals.

Note YW3.2: Beginning in the 1979 survey year, the separate "moved outside the U.S." coding category was added as a reason for noninterview and the "unable to locate" coding category no longer included those respondents who had moved outside the United States.

Note YW3.3: Congressional refusal refers to a congressional representative requesting a respondent not be contacted again for the NLS after a respondent has completed one or more survey rounds.

Note YW3.4: In 2003, interviewers sought out respondents in retirement communities, assisted living situations, and nursing homes.

The reason for noninterview coding categories depicted in Tables YW4 were constructed from the raw coding categories as shown in Table YW3. For example, the conceptual category "can't locate" is the sum of codes "1" and "4." Table YW4 depicts the count of non-interviewed by reason and survey year.

Table YW4. 'Reason for Noninterview': Young Women 1969-2003
Survey Year Total Interviewed Total Not Interviewed Can't Locate Interview Impossible Refusal Out of Scope
Note YW4.1
Deceased Dropped
Note YW4.2
1969 4930 229 52 68 98 9 2  
1970 4766 393 93 113 173 7 7  
1971 4714 445 73 78 227 8 11 48
1972 4625 534 51 67 301 5 17 93
1973 4424 735 92 69 417 4 21 132
1975 4243 916 109 77 531 2 26 171
1977 4108 1051 95 61 644 2 29 220
1978 3902 1257 69 40 824 27 33 264
1980 3801 1358 45 26 910 25 41 311
1982 3650 1509 54 18 1031 28 47 331
1983 3547 1612 37 12 1153 30 49 331
1985 3720 1439 359 115 727 49 58 131
1987 3639 1520 100 47 1016 29 71 257
1988 3508 1651 111 60 1119 22 83 256
1991 3400 1759 180 39 1150 31 104 255
1993 3187 1972 215 108 1248 27 120 254
1995 3019 2140 210 170 1347 18 141 254
1997 3049 2110 274 103 1264 29 187 253
1999 2900 2259 295 89 1366 27 232 250
2001 2806 2353 295 209 1295 29 276 249
2003 2859 2300 176 131 1401 29 315 248

Note: This table is based on R00854.00, R01453.20, R02525.20, R03353.20, R04171.20, R05195.20, R05483.20, R05874.30, R07099.30, R07564.70, R08032.70, R09473.40, R10628.40, R11092.40, R12327.40, R13652.40, R16014.20, R34985.20, R42671.20, R63203.30, and R76154.00.

Note YW4.1: Beginning in 1978, "moved outside the U.S." became a separate out-of-scope coding category. Respondents who could not be interviewed during the 1969-77 interviews because their residence--either within or outside of the U.S.--was too far away were coded within the "interview impossible" category. Out-of-scope counts for pre-1978 survey years may thus be understated.

Note YW4.2: Respondents who had been noninterviews for two consecutive survey years due to reasons other than refusal or death were eliminated from the eligible sample beginning with the 1970 interview. After 1982, no additional respondents were dropped based on this rule; in 1985, an attempt was made to reinterview some dropped individuals. Some individuals previously coded as "dropped from sample" were coded differently in later surveys.

Young Women sample representativeness and attrition

The retention rate for the Young Women at the final interview was 55.4 percent, or 2,859 of the original 5,159 respondents. Retention rate is defined as the percent of base-year respondents who were interviewed in any given survey year; included in the calculations are deceased and other out-of-scope respondents An analysis of selected characteristics of respondents interviewed in the tenth year samples of the Original Cohorts found that noninterviews had not seriously distorted the sample representativeness of any of the cohorts for the characteristics studied (Rhoton 1984). A second analysis of differential attrition among wealthy and non-wealthy subsamples of each of the four Original Cohorts found that non-wealthy respondents of each cohort showed a consistent tendency toward greater attrition (Rhoton and Nagi 1991). Among the three younger cohorts, almost all of the difference between wealthy and non-wealthy subsamples is accounted for by attrition reasons other than the death of the respondent. In a more recent analysis, Zagorsky and Rhoton (1998) concluded that respondents with lower socio-economic status attrited at a higher rate than those with higher income and educational attainment. Further, the authors found that white respondents were more likely to remain in the survey than blacks and those of other races.

In Table YW5, the percentage of sampled respondents of each race is presented for the base survey year (1968) and for 2003, the final year the survey was fielded. This table also provides information on numbers of deceased respondents by race.

Table YW5. Sample characteristics by race: Young Women 1968 and 2003
Race
Note YW5.1
# of Interviewed Respondents Retention,
2003 as % of 1968
Number of Deaths
as of 2003
Note YW5.2
1968 2003
Non-black 3700 (71.7 %) 2115 (74.0%) 57.16% 171
Black 1459 (28.3 %) 744 (26.0%) 50.99% 144

Note YW5.1: See section on Race, Ethnicity & Nationality for details on race classifications. Respondent totals in this table are based on R00032.00.

Note YW5.2: Numbers are derived from R76154.00, a revised created variable that reflects mortality counts based on Social Security Administration records.

References

Rhoton, Patricia. "Attrition and the National Longitudinal Surveys of Labor Market Experience: Avoidance, Control and Correction." Columbus, OH: CHRR, The Ohio State University, 1984.

Rhoton, Patricia and Nagi, Karima. "Attrition by Wealth in the Original NLS Cohorts." Columbus, OH: CHRR, The Ohio State University, 1991.

Zagorsky, Jay and Rhoton, Pat. "Attrition and the National Longitudinal Surveys' Mature Women Cohort." Columbus, OH: CHRR, The Ohio State University, 1998.

Interview Methodology

Interview schedule and fielding periods

In the initial survey plan, respondents from each of the four Original Cohorts were to be interviewed yearly over a five-year period. However, due to cost considerations, it was decided after the second survey of the Older Men to survey the two older groups (Older Men and Mature Women) biennially rather than annually. In order to permit a survey at the end of the five-year period, Mature Women respondents were interviewed in both 1971 and 1972. Due to their greater mobility, the Young Women and Young Men were interviewed annually.

A decision was made at the end of the first five-year period to continue the interviews for another five years because of the usefulness of these data and the relatively small sample attrition. At this point, the interviewing pattern changed to a 2-2-1 schedule; each respondent was contacted by phone approximately every two years, then again in person one year after the second phone interview. The 2-2-1 schedule was continued through 1988 for the Young Women and 1987 for the Mature Women, when the decision was made to conduct a personal interview every other year. However, the implementation of the biennial schedule was interrupted by the 1990 decennial Census. Thus, the scheduled 1990 Young Women survey was pushed back to 1991. 

Tables 1a and 1b depict the years in which each cohort was surveyed, the type of interview used, the fielding period, and the number and percent of respondents with completed interviews. Users should note that, in years during which the survey was conducted in person, some interviews were administered by telephone when necessary.

Table 1a. Mature Women sample sizes, retention rates, and fielding periods
Year Primary Type of Interview
Note 1a.1
Fielding Period Total Interviewed Retention Rate
Note 1a.2
Retention Rate, Living Respondents Only
Note 1a.3
1967 Personal May-July 5083 100.0% 100.0%
1968 Mail May-July 4910 96.6% 97.0%
1969 Personal May-July 4712 92.7% 93.3%
1971 Personal April-June 4575 90.0% 91.0%
1972 Personal April-June 4471 88.0% 89.3%
1974 Telephone April-June 4322 85.0% 86.7%
1976 Telephone April-June 4172 82.1% 84.2%
1977 Personal April-June 3964 78.0% 80.3%
1979 Telephone April-June 3812 75.0% 77.8%
1981 Telephone April-June 3677 72.3% 75.8%
1982 Personal July-September 3542 69.7% 73.4%
1984 Telephone April-June 3422 67.3% 71.8%
1986 Telephone July-September 3335 65.6% 71.1%
1987 Personal July-September 3241 63.8% 69.5%
1989 Personal June-August 3094 60.9% 67.6%
1992 Personal October-December 2953 58.1% 66.6%
1995 Personal June-September 2711 53.3% 63.5%
1997 Personal July-September 2608 51.3% 63.7%
1999 Personal June-August 2467 48.5% 62.4%
2001 Personal June-August 2318 45.6% 61.8%
2003 Personal June-August 2237 44.0% 62.2%

Note 1a.1: Even in years during which the survey was conducted in person, some interviews were administered by telephone when that was the best way to complete a case.

Note 1a.2: Retention rate is defined as the percent of base-year sample members who were interviewed in any given survey year. Included in the calculations are deceased and institutionalized sample members, as well as those serving in the military.

Note 1a.3: This retention rate excludes sample members known to be deceased in each survey year.

Table 1b. Young Women sample sizes, retention rates, and fielding periods
Year Primary Type of Interview
Note 1b.1
Fielding Period Total Interviewed Retention Rate
Note 1b.2
Retention Rate, Living Respondents Only
Note 1b.3
1968 Personal January-March 5159 100.0% 100.0%
1969 Personal January-March 4930 95.6% 95.6%
1970 Personal January-March 4766 92.4% 92.5%
1971 Personal January-March 4714 91.4% 91.6%
1972 Personal January-March 4625 89.6% 90.0%
1973 Personal January-March 4424 85.8% 86.1%
1975 Telephone January-March 4243 82.2% 82.7%
1977 Telephone January-March 4108 79.6% 80.1%
1978 Personal January-March 3902 75.6% 76.1%
1980 Telephone January-March 3801 73.7% 74.3%
1982 Telephone January-March 3650 70.8% 71.4%
1983 Personal January-March 3547 68.8% 69.4%
1985 Telephone January-March 3720 72.1% 72.9%
1987 Telephone January-March 3639 70.5% 71.5%
1988 Personal May-July 3508 68.0% 69.1%
1991 Personal May-August 3400 65.9% 67.3%
1993 Personal September-November 3187 61.8% 63.2%
1995 Personal June-September 3019 58.5% 60.2%
1997 Personal June-September 3049 59.1% 61.3%
1999 Personal June-August 2900 56.2% 58.9%
2001 Personal June-August 2806 54.4% 57.5%
2003 Personal June-August 2859 55.4% 59.0%

Note 1b.1: Even in years during which the survey was conducted in person, some interviews were administered by telephone when that was the best way to complete a case.

Note 1b.2: Retention rate is defined as the percent of base-year sample members who were interviewed in any given survey year. Included in the calculations are deceased and institutionalized sample members, as well as those serving in the military.

Note 1b.3: This retention rate excludes sample members known to be deceased in each survey year.

Important information: Interview modes

Although each of the personal interviews contains data of roughly the same degree of completeness, data gathered during the telephone interviews were not meant to update the longitudinal record of a respondent. Rather, the telephone interviews were intended to obtain a brief update of information on each respondent and to maintain sufficient contact so that the lengthier personal interview could be completed. The combination of fluctuating fielding periods and type of interview (i.e., personal or phone) may affect not only the probability of reinterview but also the reference periods of time-related questions.

There is another source of inconsistency with respect to time references. A given year's survey instrument may use the previous calendar year as a reference period for some questions, while other questions will collect data for the year since last interview. Income data, for example, were often collected for the calendar year, corresponding to the time frame for a respondent's tax records; employment data were usually collected for the year since the last interview. In most cases the variable titles will indicate the time period covered.

Interview methods

Listings of respondents to be interviewed were generated by the Census Bureau and distributed to its 12 regional offices. Current addresses and contact information were generated from data collected during the last interview and through a postal check conducted by Census. Cases were assigned to interviewers who lived in the same geographic area as the respondent. Interviewers then received copies of the questionnaire (or a laptop computer for computer-assisted personal interviews (CAPI)) and (if used) respondents' Household Record Cards and flashcard and/or information booklets.

In each survey round, interviewers were responsible for contacting each respondent in their caseload and for using additional local level resources to locate those respondents who had moved since the last interview. Respondents who had moved outside the geographic district of their original interviewer were assigned to another unless there were no personnel nearby. In the latter event, an effort was made to interview the respondent by telephone.

Each respondent to be interviewed was sent various materials designed to encourage continued participation. Advance letters thanking respondents for taking part in the interviews and informing them of the coming survey were mailed prior to each interview period. Fact sheets highlighting recent research findings from each cohort's survey data were also provided. Respondents who had initially refused to participate in a survey were sent letters and some additional materials by the regional offices designed to encourage their continued participation and were once again contacted by local level interviewers to secure the interview.

While the type of survey, personal or telephone, determined the chief mode of contact, an alternate contact method was used for certain respondents. During a personal survey, for example, those respondents who lived long distances from the Census interviewer's base of operation or those for whom the Census supervisor has decided that another contact method was warranted were contacted by telephone. Although survey instruments are written in English only, multilingual interpreters were made available by the regional offices to interviewers who needed them.

Beginning in 1995, respondents in the two women's cohorts were interviewed during the same time period; a single computer-assisted personal interview (CAPI) replaced the separate paper-and-pencil interview (PAPI) instruments used during the previous interviews. While data were collected simultaneously for the two cohorts, they were released separately by cohort. This CAPI interview continued on a biennial basis through 2003 when the survey ended.

The average length of an interview varied depending on the type conducted, with personal PAPI interviews lasting 50-60 minutes, telephone PAPI interviews averaging 20-25 minutes, and CAPI interviews lasting about 70 minutes. As a validation check, a percentage of the respondents were contacted following the interviews to ascertain that the interviews had taken place. No stipends were paid to Original Cohort respondents for their participation until 2003. During the 2003 fielding, a special incentive experiment was conducted to see how a subset of respondents responded to being offered money to participate. Variables associated with this incentive experiment are R65017.00, R76056.00-R76060.00, R76105.10, and R76105.20.

Sample Design and Screening Process

Sample design

Each of the original NLS samples was designed to represent the civilian noninstitutionalized population of the United States at the time of the initial survey. The Mature Women cohort includes individuals who were ages 30-44 as of March 31, 1967, and the Young Women cohort consists of respondents ages 14-24 as of December 31, 1967.

Each cohort is represented by a multi-stage probability sample drawn by the Census Bureau from 1,900 primary sampling units (PSUs) that had originally been selected from the nation's counties and cities for the experimental Monthly Labor Survey conducted between early 1964 and late 1966. A primary sampling unit consists of Standard Metropolitan Statistical Areas (SMSAs), counties (or parishes in some states), parts of counties, and independent cities. A total of 235 sample areas, comprising 485 counties and independent cities, were chosen to represent every state and the District of Columbia. 

From the sample areas, 235 strata were created of one or more PSUs that were relatively homogeneous according to socioeconomic characteristics. Within each stratum, a single PSU was selected to represent the stratum. Finally, within each PSU, a probability sample of housing units was selected to represent the civilian noninstitutionalized population. Because the addresses for the sample frame came from the 1960 Census, respondents are covered by Title 13 confidentiality restrictions. Variables linked to geographic residence, including county and state, are available for use at Census Data Centers.

Restricted-use data

Information about access to restricted-use geographic and school survey data is available on the Accessing Data page.

Screening process

The initial sample of about 42,000 housing units for all four NLS Original Cohorts was selected and screening interviews took place in March and April of 1966. Of this number, about 7,500 units were found to be either vacant, occupied by persons whose usual residence was elsewhere, changed from residential use, or demolished. On the other hand, about 900 additional units were found created within existing living space or changed from what had been nonresidential space. A total of 35,360 housing units were available for interview, from which usable information was collected for 34,662 households for a completion rate of 98.0 percent.

The original plan called for using the initial screening to select all four NLS Original Cohorts. However, after the sample members for the Older Men were chosen, the sample was rescreened in September 1966 before the initial interview of the Young Men. This decision was made because a seven-month delay between the screening and first interview seemed inordinate due to the mobility of young men in their late teens and early twenties. To increase efficiency, it was decided to stratify the sample for the rescreening by the presence or absence of a 14- to 24-year-old male in the household. The probability was high that a household that contained a 14- to 24-year-old in March would also have such a member in September. However, to insure that the sample also represented persons who had moved into sample households in the intervening period, a sample of addresses that previously had no 14- to 24-year-old males was also included in the rescreening operation. Since a telephone number had been recorded for most households at the time of the initial screening interview, every attempt was made to complete the short screening interview by telephone. The sample of households from the initial screening, supplemented with information from the rescreening, was subsequently used to obtain the two samples of women ages 30-44, the Mature Women, and ages 14-24, the Young Women (Parnes et al. 1970; Shea et al. 1971).

Important information: Screening process

During the screening process a large number of multiple respondent households were designated for interview; more than half of respondents in the Mature Women, Young Women, and Young Men cohorts and one third of respondents in the Older Men cohort originated from multiple respondent households (i.e., a household with at least one other respondent). For more information on multiple respondent households and on the types of relationships that existed between respondent pairs (e.g., spouse, sibling, etc.), see the Household Composition section.

Sampling process

Following the initial household interview and rescreening operation, 5,393 women ages 30-44 as of March 31, 1967, were designated to be interviewed for the Mature Women cohort, while 5,533 women ages 14-24 as of December 31, 1967, were designated to be interviewed for the Young Women cohort. The sample was designed to provide approximately 5,000 respondents--about 1,500 nonwhites and 3,500 whites. The women were sampled differentially within four strata:  whites in predominantly white enumeration districts (EDs), non-whites in predominantly non-white EDs, whites in predominantly non-white EDs, and non-whites in predominantly white EDs. An enumeration district is a geographical area considered to be an appropriate size for an interviewer to complete all necessary interviews within a prescribed time frame. 

To provide separate reliable statistics for black respondents, the sample design called for oversampling of blacks at twice the expected rate in the total population. The sampling rate of households in predominantly non-white EDs was between three and four times that for households in predominantly white EDs in order to meet this survey requirement. Among the individuals designated for interview, 5,083 (94.3 percent) of the Mature Women were interviewed in 1967, and 5,159 (93.2 percent) of the Young Women were interviewed in 1968.

Mature and Young Women Cohorts: An Introduction

Mature Women cohort

Official title

National Longitudinal Survey of Mature Women part of the Original Cohorts from the National Longitudinal Surveys (NLS) program.

Status of survey

Not active. The most recent interviews of the Mature Women respondents took place in 2003.

Age of cohort

Born between 1922 and 1937. At the time of first interview, Mature Women respondents' ages ranged from 30 to 44. The respondents were 59 to 85 at the time of their last interviews in 2003.

Number of respondents in the survey

5,083 individuals were initially interviewed in round 1. Approximately 44 percent (2,237) of the round 1 sample were interviewed in 2003, the last survey year.

Gender

All women. The NLS Original Cohorts project also interviewed two men's cohorts, the Older Men and Young Men cohorts.

Race/ethnicity (in initial survey)

  • White: 3,606 (70.9%)
  • Black: 1,390 (27.3%)
  • Other: 87 (1.7%)

Number of survey rounds available to the public

21 rounds. Mature Women respondents were surveyed regularly, either every year or every other year. Public data are available for no charge at www.nlsinfo.org/investigator

Types of information gathered in the survey

Funding Sources for the Mature Women

The Mature Women interviews were originally sponsored by the Office of Manpower, Automation, and Training (now the Employment and Training Administration), part of the U.S. Department of Labor. The Bureau of Labor Statistics (BLS) provided funding for later rounds of the survey and currently oversees the NLS program.


Young Women cohort

Official title

National Longitudinal Survey of Young Women, part of the Original Cohorts from the National Longitudinal Surveys (NLS) program.

Status of survey

Not active. The most recent interviews of the Young Women respondents took place in 2003.

Age of cohort

Born between 1943 and 1953. At the time of first interview, respondents' ages ranged from 14 to 24. The respondents were 49 to 61 at the time of their last interviews in 2003.

Number of respondents in the survey

5,159 individuals were initially interviewed in round 1. For the last fielding period in 2003, a total of 2,859 women were interviewed, 55.4% of the original sample.

Gender

All women. The NLS Original Cohorts project also interviewed a similar cohort of Young Men that was the same 14-24 age range, as well as the Older Men cohort.

Race/ethnicity (in initial survey)

  • White: 3,638 (70.5%)
  • Black: 1,459 (28.3%)
  • Other: 62 (1.2%)

Number of survey rounds available to the public

22 rounds. Young Women respondents were surveyed annually between 1968-1973. After 1973, they were generally interviewed every other year or every third year, with the exception of being interviewed two years in a row in 1982 and 1983.  Public data are available for no charge at www.nlsinfo.org/investigator.

Types of information gathered in the survey

Funding sources for the Young Women

The Young Women interviews were originally sponsored by the Office of Manpower, Automation, and Training (now the Employment and Training Administration), part of the U.S. Department of Labor. The Bureau of Labor Statistics (BLS) provided funding for later rounds of the survey and currently oversees the NLS program.

Cigarette Use

Mature Women cohort

Information on the use of cigarettes was collected only in the 1989 and 1995-2003 surveys. The 1989 survey included questions for both current and past users. Respondents were asked the age when they first started smoking regularly and the number of cigarettes/packs they smoked on a usual day. Respondents who had stopped smoking as of the interview date provided the age when they last smoked regularly. The 1995-2003 surveys simply asked whether or not respondents currently smoked. Table MW1 provides reference numbers for the cigarette use questions.

Table MW1. Reference Numbers of Cigarette Use Questions
Question 1989 1995 1997 1999 2001 2003
Do you smoke cigarettes now? R09608.00          
Do you smoke cigarettes?   R33654.00 R41338.00 R50910.00 R61846.00 R72892.00
On the average, how many cigarettes do you usually smoke in a day (present smoker)? R09609.00, R09610.00          
How old were you when you first started smoking regularly (present smoker)? R09612.00          
Did you ever smoke cigarettes? R09613.00          
On the average, how many cigarettes did you usually smoke in a day (past smoker)? R09614.00, R09615.00          
How old were you when you last smoked regularly (past smoker)? R09617.00          
How old were you when you first smoked regularly (past smoker)? R09618.00          
Survey Instruments The "Health" sections of the 1989 and 1995-2003 surveys contain the questions on cigarette use.

Young Women cohort

Information on the use of cigarettes was collected in the 1991-2003 surveys. The 1991 survey included questions for both current and past users. Respondents were asked the age when they first started smoking regularly and the number of cigarettes/packs they smoked on a usual day. Respondents who had stopped smoking as of the interview date provided the age when they last smoked regularly. The 1993 survey collected information only about current smoking behavior. In 1995-2003, respondents were asked one question, "Do you smoke cigarettes?" Table YW1 provides reference numbers for cigarette use questions.

Table YW1. Reference Numbers of Cigarette Use Questions
Question 1991 1993 1995 1997 1999 2001 2003
Do you smoke cigarettes now? R13020.00 R14711.00          
Do you smoke cigarettes?     R33654.00 R41338.00 R50910.00 R61846.00 R72892.00
On the average, how many cigarettes do you usually smoke in a day (present smoker)? R13021.00, R13022.00 R14712.00, R14713.00          
How old were you when you first started smoking regularly (present smoker)? R13024.00            
Did you ever smoke cigarettes? R13025.00            
On the average, how many cigarettes did you usually smoke in a day (past smoker)? R13026.00, R13027.00            
How old were you when you last smoked regularly (past smoker)? R13029.00            
How old were you when you first smoked regularly (past smoker)? R13030.00            
Survey Instruments The "Health" sections of the 1991-2003 surveys contain the questions on cigarette use.

Alcohol Use

Mature Women cohort

Respondents were asked about their use of alcohol in the 1991-2003 surveys. The 1991 instrument included questions on the frequency with which the respondent drank alcoholic beverages such as beer, wine, or liquor during her adult life and in the last 30 days, and, if she drank, the quantity and type of alcohol usually consumed per day. In subsequent surveys, a smaller set of questions addressed frequency and quantity of alcohol used during the past month. Table MW1 lists reference numbers for questions concerning alcohol consumption.

Table MW1. Reference Numbers of Alcohol Use Questions
Question 1991 1993 1995 1997 1999 2001 2003
In your entire life, did you have at least 12 drinks of any kind of alcoholic beverage? R13031.00            
On the average, during your adult life, how often did you drink any alcoholic beverages? R13032.00            
Have you had any alcoholic beverages since the date of last interview?     R33655.00 R41339.00 R50911.00 R61847.00 R72893.00
Have you had any alcoholic beverages during the last 30 days? R13033.00 R14715.00 R33656.00 R41340.00 R50912.00 R61848.00 R72894.00
During the last 30 days, on how many days did you drink any alcoholic beverages? R13034.00 R14716.00         --
Thinking back to the last day you had a drink, about how many drinks did you have that day?     R33657.00 R41341.00 R50913.00 R61849.00 R72895.00
On the days that you drink, about how many drinks do you have on the average day? R13036.00 R14718.00 R33658.00 R41342.00 R50914.00 R61850.00 R72896.00
Survey Instruments The "Health" sections of the 1991-2003 surveys contain the questions about alcohol use.

Young Women cohort

Respondents were asked about their use of alcohol in the 1991-2003 surveys. The 1991 instrument included questions on the frequency with which the respondent drank alcoholic beverages such as beer, wine, or liquor during her adult life and in the last 30 days, and, if she drank, the quantity and type of alcohol usually consumed per day. In subsequent surveys, a smaller set of questions addressed frequency and quantity of alcohol used during the past month. Table YW1 lists reference numbers for questions concerning alcohol consumption.

Table YW1. Reference Numbers of Alcohol Use Questions
Question 1991 1993 1995 1997 1999 2001 2003
In your entire life, did you have at least 12 drinks of any kind of alcoholic beverage? R13031.00            
On the average, during your adult life, how often did you drink any alcoholic beverages? R13032.00            
Have you had any alcoholic beverages since the date of last interview?     R33655.00 R41339.00 R50911.00 R61847.00 R72893.00
Have you had any alcoholic beverages during the last 30 days? R13033.00 R14715.00 R33656.00 R41340.00 R50912.00 R61848.00 R72894.00
During the last 30 days, on how many days did you drink any alcoholic beverages? R13034.00 R14716.00          
Thinking back to the last day you had a drink, about how many drinks did you have that day?     R33657.00 R41341.00 R50913.00 R61849.00 R72895.00
On the days that you drink, about how many drinks do you have on the average day? R13036.00 R14718.00 R33658.00 R41342.00 R50914.00 R61850.00 R72896.00
Survey Instruments The "Health" sections of the 1991-2003 surveys contain the questions about alcohol use.

Activities

Mature Women cohort

The Mature Women respondents were asked about a variety of activities throughout the survey years, including household chores, leisure activities, driving, and use of community services.

Household chores

In 1982, 1984, and 1987, respondents answered a series of questions about household chores, with the emphasis on whether the chore was the respondent's sole responsibility, shared responsibility, or the responsibility of others. These chores included grocery shopping, child care, caregiving for the ill or disabled (only in 1984 and 1987), cooking, cleaning dishes, cleaning house, washing clothes, yard and home maintenance, and family paperwork. Respondents also estimated the number of hours spent per week on all household tasks combined.

In the 1999 through 2003 surveys, respondents indicated how much time they spent helping family members (adult children and mothers and fathers) with household chores. They also answered questions about any time their children spent helping them. The Transfers section includes more information about this series of questions.

Areas of Interest Household Chores

Leisure activities

In 1967, the first year of the survey, respondents were asked about any non-work, non-housework activities: home activities, social activities away from home, or clubs/education/church activities. If they had no time for these leisure activities they indicated as such.

Areas of Interest Household Chores

Automobile driving

A series of questions about driving vehicles was asked in 1995.  Respondents answered questions about the number of miles driven in the 12 months prior to the interview, whether they had driven after dark during that time period, and, if they weren't driving at the time of the interview, what year they last drove and what was the main reason they stopped driving.

Areas of Interest Health Status

Use of community services

In 2003, the final year of data collection, respondents answered a series of questions about community services they might have used in the 12 months prior to the interview. These services included transportation for the elderly, Meals on Wheels, meals at a senior center, homemaker services, telephone check services, visiting nurse or health aide, or adult day care. They also answered a question about how much help they could expect from family, friends or other people if they had a problem and needed help.

Related Variables The Labor Force Status section provides information on "Activity Most of Work Week" responses, while the Job Search section indicates activities undertaken for seeking a job. Information about health-related restrictions on activities can be found in the Physical Health section. For activities related to volunteering, see the Volunteerism section.
Survey Instruments & Documentation Questions on activities can be found in various questionnaire sections, including "Health," "Other Family Background," "Intra-family Transfers," and "Attitudes."
Areas of Interest Health Status

Young Women cohort

The Young Women respondents were asked about a variety of activities throughout the survey years, including household chores, extra-curricular school activities, and driving.

Household chores

In 1972, young women respondents gauged the average time they spent weekly on household activities. These activities included food preparation and cleanup, house cleaning, clothing care, child care, and shopping. 

In 1983, respondents answered another series of questions about household chores. This time the emphasis was on whether the chore was the respondent's sole responsibility, shared responsibility, or the responsibility of others. These chores included grocery shopping, child care, cooking, cleaning dishes, cleaning house, washing clothes, yard and home maintenance, and family paperwork. Respondents also estimated the number of hours spent per week on all household tasks combined.

In the 1999 through 2003 surveys, respondents indicated how much time they spent helping family members (adult children and mothers and fathers) with household chores. They also answered questions about any time their children spent helping them. The Transfers section includes more information about this series of questions.

Areas of Interest Household Chores

Extra-curricular school activities

In the initial year of the survey in 1968, respondents were asked if they took part in any extra-curricular activities during their last full year of high school, how much time was spent weekly on the activities, and which activity was their favorite.  Respondents were also asked what non-school-related activity--hobby, reading, work for pay, helping at home, or non-school related sports--took up the most of their extra time during that last year of high school.

Areas of Interest Education

Automobile driving

A series of questions about driving vehicles was asked in 1995.  Respondents answered questions about the number of miles driven in the 12 months prior to the interview, whether they had driven after dark during that time period, and, if they weren't driving at the time of the interview, what year they last drove and what was the main reason they stopped driving.

Related Variables The Labor Force Status section provides information on "Activity Most of Work Week" responses, while the Job Search section indicates activities undertaken for seeking a job. Information about health-related restrictions on activities can be found in the Physical Health section. For activities related to volunteering, see the Volunteerism section.
Survey Instruments & Documentation Questions on activities can be found in various questionnaire sections, including "Health," "Other Family Background," "Intra-family Transfers," and "Attitudes."
Areas of Interest Health Status

Volunteerism

Mature Women cohort

Respondents in the Mature Women cohort were asked a series of questions about unpaid volunteer work in survey years 1974, 1976, 1979, 1981, 1984, 1987, and 2003.  This series included questions about the number of weeks and hours per week spent volunteering, the type of organization (such as hospital, youth organizations, church, civic or political organizations, or schools), and the reasons the respondent gave for volunteering.  In 1979, respondents rated how much they liked or disliked their activities with the volunteer organization. In 1981 and 1984, respondents answered additional questions about any activities aimed at changing social conditions (such as working with environmental, consumer, or minority groups). In 1979,  respondents were asked if they held an office in the volunteer organization where they worked and if so, which office (president, chair, etc.).

In most of the survey years from 1984 through 2003, respondents answered questions about caregiving: regularly helping with the needs of a relative or a friend inside the household or helping relatives or friends outside the household.

Survey Instruments & Documentation Questions about volunteerism can be found in the "Work Attitudes" section of the questionnaires. Questions about caregiving can be found in the "Health" section of the questionnaires.
Areas of Interest Volunteer Work

Young Women cohort

Respondents in the Young Women cohort were asked a series of questions about unpaid volunteer work in survey years 1973, 1978, 1988, 1991, 1995, and 2003.  This series included questions about the number of weeks and hours per week spent volunteering, the type of organization (such as hospital, youth organizations, church, civic or political organizations, or schools), and the reasons the respondent gave for volunteering.  In 1991 and 2003, respondents answered additional questions about any activities aimed at changing social conditions (such as working with environmental, consumer, or minority groups). In 1988,  respondents were asked if their volunteer work resulted in finding work for pay. Respondents were asked in 1978 and 1995 about childcare needs for the time volunteered.

In the survey years from 1991 through 2003, respondents answered questions about caregiving: regularly helping with the needs of a relative or a friend inside the household or helping relatives or friends outside the household.

Survey Instruments & Documentation Questions about volunteerism can be found in the "Work Attitudes" section of the questionnaires. Questions about caregiving can be found in the "Health" section of the questionnaires.
Areas of Interest Volunteer Work
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