NLSY79

Retention vs. Response Rate

Retention rates for NLSY79 respondents from 1979 to 1993 exceeded 90 percent. Rates from 1994 until 2000 exceeded 80 percent. Rates from 2002 until 2014 were in the 70s. Retention rate is calculated by dividing the number of respondents interviewed by the number of respondents remaining eligible for interview. All 1979 (round 1) respondents including those reported as deceased are eligible for interviews, with the exception of those who have been permanently dropped from the sample. In the round 29 (2020) survey, 6,535 civilian and military respondents out of the 9,964 eligible were interviewed, for an overall retention rate of 65.6 percent. Retention rates for each survey are shown in Table 1. This table also shows which interviews were conducted with paper-and-pencil interviewing (PAPI) and which were executed with computer-assisted personal interviewing (CAPI).

The number of respondents can also be expressed as a percentage of the number of base year respondents not known to be deceased. This is referred to as the response rate and is reported in Table 2 for each survey round. As of 2020, 1,185 main respondents had been reported as deceased. The response rate for those believed to be alive is 74.4 percent.

Reasons for Noninterview

A 'Reason for Noninterview' variable is constructed for each survey year (excluding 1979) in the NLSY79 and provides an explanation of why an interview could not be conducted or completed with a respondent. The cause of noninterview is assigned by the NORC interviewer to each respondent designated as a member of the eligible sample for a given survey year. Typical coding categories have included reasons such as an interview being refused by the respondent or by the respondent's parent, the respondent or family unit not being located, or the respondent being reported as deceased.

Beginning in the 1980s, two administrative categories were added. One reflected a decision by NORC not to attempt to interview certain sample members who were determined to be extremely difficult to interview. The second category indicates that, due to funding cutbacks, interviews would not be attempted with certain members of one or more of the NLSY79 subsamples. Thus, beginning in 1985, interviews ceased for 1,079 respondent members of the military subsample; each was permanently assigned a reason for noninterview of "military sample dropped." A second group of respondents, those belonging to the supplemental economically disadvantaged, nonblack/non-Hispanic sample, was similarly dropped from interviewing beginning with the 1991 survey. The target universe for each survey year--that is, the respondents whom NORC attempts to interview--thus includes all respondents interviewed in the initial survey year exclusive of those who were:

1. reported deceased at an earlier interview
2. dropped from the sample
3. judged to be extremely difficult to interview

Table 3 presents the number of respondents not interviewed across survey years by sample type.

Sample Representativeness & Attrition

This section reviews the number of respondents by race, sex, and NLSY79 sample type who have continued to be interviewed during all surveys. It also takes a brief look at the racial composition of the cohort at the initial and latest survey points. Table 4 shows the number of respondents, excluding dropped respondents, who were interviewed at all survey points. This table exhibits the high degree of NLSY79 retention. From 1979 to 2020 the survey has been administered 29 times.

Table 5 shows the distribution of the number of interviews completed by respondents, broken down by sample type. The "# who completed" column shows how many respondents completed exactly that number of surveys. These numbers refer to any surveys completed since the NLSY79 began, not necessarily consecutive surveys completed or surveys completed in particular years. The cumulative percent column shows a cumulative total percent of those completing at least a given number of surveys rather than a percentage of those completing an exact number of surveys. Readers should note the attrition suggested in Table 3 greatly overstates the amount of lost information. The NLSY79 asks detailed questions about work history, education, training, marital status, and fertility since the date of the respondent's last interview. These retrospective questions capture information lost due to missed interviews. Hence, a perfect response record is not needed for researchers to understand how the respondent's life changes over time, unless he or she leaves the survey forever.

• Household Interview Section for NLSY79 Rnd 30 Questionnaire

• Migration History and Family Background Section for NLSY79 Rnd 30 Questionnaire

• Marital History Section for NLSY79 Rnd 30 Questionnaire

• Military Section for NLSY79 Rnd 30 Questionnaire

• On Jobs Section for NLSY79 Rnd 30 Questionnaire

• Employer Supplement Section for NLSY79 Rnd 30 Questionnaire

• Business Ownership Section for NLSY79 Rnd 30 Questionnaire

• Business Match Section for NLSY79 Rnd 30 Questionnaire

• Gaps Section for NLSY79 Rnd 30 Questionnaire

• Perceived Discrimination Section for NLSY79 Rnd 30 Questionnaire

• Training Section for NLSY79 Rnd 30 Questionnaire

• Spouse Labor Information Section for NLSY79 Rnd 30 Questionnaire

• Fertility Section for NLSY79 Rnd 30 Questionnaire

• Health Section for NLSY79 Rnd 30 Questionnaire

• Income and Recipiency Section for NLSY79 Rnd 30 Questionnaire

• Retirement Expectations Section for NLSY79 Rnd 30 Questionnaire

• Wills Section for NLSY79 Rnd 30 Questionnaire

• Interview End Section for NLSY79 Rnd 30 Questionnaire

• Locator Section for NLSY79 Rnd 30 Questionnaire

• Interviewer Remarks Section for NLSY79 Rnd 30 Questionnaire

The NLS program has established set procedures for ensuring respondent confidentiality and obtaining informed consent. These procedures comply with Federal law and the policies and guidelines of the U.S. Office of Management and Budget (OMB) and the U.S. Bureau of Labor Statistics:

• OMB Procedures and Federal Laws
• Survey Procedures
• Data Handling

OMB Procedures and Federal Laws

OMB Procedures

The Office of Management and Budget (OMB) is responsible for setting overall statistical policy among Federal agencies. For example, OMB has established standards on collecting information about race and ethnicity, industry, occupation, and geographic location. OMB also has established standards on the manner and timing of data releases for such principal economic indicators as the gross domestic product, the national unemployment rate, and the Consumer Price Index. In addition, OMB sets standards on whether and how much respondents to Federal surveys can be paid for their participation, an issue of particular concern in the NLS program.

Another of OMB's responsibilities is to review the procedures and questionnaires that Federal agencies use in collecting information from 10 or more respondents. Federal data collections reviewed by OMB include administrative data, such as the tax forms that the Internal Revenue Service requires individuals and corporations to complete. OMB also reviews all censuses and surveys that Federal agencies conduct, either directly or through contracts.

Surveys that are funded through Federal grants to universities and other organizations generally do not have to undergo this OMB review process unless the grantee in turn contracts with a Federal statistical agency such as the Census Bureau to collect the data. In place of OMB review, surveys funded through grants typically must undergo a competitive peer-review process established by the agency administering the grant, and that review process examines the procedures for maintaining respondent confidentiality and obtaining the informed consent of the participants. In addition, such surveys also typically are scrutinized by an institutional review board established at the grantee's institution.

OMB examines a variety of issues during these reviews, such as the:

• amount of time (and money, if any) that the agency collecting the information estimates respondents will spend to provide the requested information
• agency's efforts to reduce the burden on respondents of providing the information
• purpose and necessity of the data collection, including whether it duplicates the objectives of other Federal data collections
• ways in which the agency obtains informed consent from potential respondents to participate in the data collection
• policies and procedures that the agency has established to ensure respondent confidentiality
• statistical methods used to select representative samples, maximize response rates, and account for nonresponse
• payment of money or the giving of gifts to respondents
• questionnaire itself, including the quality of its design and whether it includes questions that respondents may regard as sensitive

These OMB reviews are very thorough. From the time an agency prepares an OMB information collection request until the time OMB approves the data collection, the process typically takes 7 months or more and includes multiple layers of review within the agency and at OMB. These reviews are helpful in improving survey quality and ensuring that agencies treat respondents properly, both in terms of providing them with information about the data collection and its uses and protecting respondent confidentiality.

The review process also provides the general public with two opportunities to submit written comments about the proposed data collection. The agency conducting the data collection publishes a notice in the Federal Register describing the data collection and inviting the public to request copies of the information collection request, questionnaires, and other materials that the agency eventually will submit to OMB. The public is invited to submit written comments to the agency sponsoring the data collection within 60 days from the time the Federal Register notice is published. In the history of the NLS program, the public very rarely has submitted comments to BLS, but when comments are received, they are summarized in the information collection request that ultimately is submitted to OMB.

After the request has been submitted to OMB, the agency sponsoring the data collection then publishes a second notice in the Federal Register and invites the public to submit comments directly to OMB within 30 days. Again, in the history of the NLS program, the public very rarely, if ever, has submitted comments to OMB. Once OMB has received the information collection request, they have 60 days to review the package, ask follow-up questions, suggest changes (or, occasionally, insist upon changes) to the survey questionnaire or procedures, and ultimately grant approval.

Respondents' Advance Letter. After OMB grants approval, the sponsoring agency can begin contacting potential respondents and collecting information from them. The process of contacting potential NLS respondents begins with sending them an advance letter several weeks before interviews are scheduled to begin. The advance letter serves several purposes. The obvious purpose is to inform respondents that an interviewer will be contacting them soon, but BLS and the organizations that conduct the surveys for BLS also use the letter to thank respondents for their previous participation and to encourage them to participate in the upcoming round. Another important objective of the advance letter is to remind respondents that their participation is voluntary and to tell them how much time the interview is expected to take. The letter also explains to respondents how the data will be used and how respondents' confidentiality will be protected by BLS and the organizations that conduct the surveys for BLS. An example of an advance letter, along with the confidentiality statement that appears on the back of the letter, is shown in Figure 1.

Figure 1. NLSY79 Round 29 Advance Letter

Institutional Review Boards

In addition to OMB review, the NLSY79 is reviewed and approved by an institutional review board (IRB) at the institutions that manage and conduct the surveys under contract with BLS. Those institutions are The Ohio State University and NORC at the University of Chicago. BLS and OMB do not require these reviews; rather, the reviews are required under the policies of the universities. Obtaining approval from the IRBs involves completing a form signed by the Principal Investigator, providing a summary of the research project and submitting a description of the consent procedures and forms used in the survey.  Additional documentation includes a copy of any materials used to recruit respondents, a detailed summary of the survey questionnaire, and any other information regarding the risks to humans of participating in the survey. OMB must review all data collections for the NLSY79.

The NLSY79 project staff at The Ohio State University Center for Human Resource Research (CHRR) and at NORC obtain approval from their respective IRBs prior to the start of each round of data collection. Because each survey includes only an interview and no invasive medical procedures, the IRBs typically focus on respondent compensation, consent procedures, and confidentiality protections for special populations, such as incarcerated or disabled respondents. Prisons, schools, and other institutions in which NLSY79 sample members may reside often request the IRB approval statement and application as evidence that appropriate procedures are being followed and to judge whether to permit NLSY79 interviewers to have access to individuals for whom the institutions are responsible.

Federal Laws

Two Federal laws govern policies and procedures for protecting respondent confidentiality and obtaining informed consent in the NLSY79 program: the Privacy Act of 1974 and the Confidential Information Protection and Statistical Efficiency Act (CIPSEA) of 2002. 

The Privacy Act and CIPSEA. These two acts protect the confidentiality of participants in the NLSY79 and its associated Child and Young Adult surveys. CIPSEA protects the confidentiality of participants by ensuring that individuals who provide information to BLS under a pledge of confidentiality for statistical purposes will not have that information disclosed in identifiable form to anyone not authorized to have it. 

In addition, CIPSEA ensures that the information respondents provide will be used only for statistical purposes. While it always has been the BLS policy to protect respondent data from disclosure through the Privacy Act and by claiming exemptions to the Freedom of Information Act, CIPSEA is important because it specifically protects data collected from respondents for statistical purposes under a pledge of confidentiality. 

This law strengthens the ability of BLS to assure respondents that, when they supply information to BLS, their information will be protected. In addition, CIPSEA includes fines and penalties for any knowing and willful disclosure of specific information to unauthorized persons by any officer, employee, or agent of BLS. Since the enactment of the Trade Secrets Act and the Privacy Act, BLS officers, employees, and agents have been subject to criminal penalties for the mishandling of confidential data, and the fines and penalties under CIPSEA are consistent with those prior laws. CIPSEA now makes such fines and penalties uniform across all Federal agencies that collect data for exclusively statistical purposes under a pledge of confidentiality.

Survey interviewers are trained how to answer questions from respondents about how their privacy will be protected. Interviewers explain to potential respondents that all the employees who work on the surveys at BLS, NORC, and CHRR are required to sign a document stating that they will not disclose the identities of survey respondents to anyone who does not work on the NLS program and is therefore not legally authorized to have such information. In fact, no one at BLS has access to information about respondents' identities, and only a few staff members at NORC and CHRR who need such information to carry out their job duties have access to information about respondents' identities.

Interviewers also explain that the answers respondents provide will be made available to researchers at BLS and other government agencies, universities, and private research organizations, but only after all personal identifiers--such as names, addresses, Social Security numbers, and places of work--have been removed. In addition, the publicly available data files exclude any information about the States, counties, metropolitan statistical areas, and other, more detailed geographic locations in which respondents live, making it much more difficult to infer the identities of respondents.

Respondents are told that some researchers are granted special access to data files that include geographic information, but only after those researchers undergo a thorough application process at BLS and sign a written agreement making them official agents of BLS and requiring them to protect the confidentiality of respondents. In no case are researchers provided with information on the personal identities of respondents.

Finally, the reference in the questions and answers to the National Archives and Records Administration and the General Services Administration may be confusing to some potential respondents, because those Federal agencies are not involved in the administration of the surveys. Interviewers explain to respondents that NLS data and materials will be made available to those agencies because they are responsible for storing the Nation's historical documents.  The information provided to those agencies does not include respondents' personal identities, however.

The organizations involved in the NLS program continuously monitor their security procedures and improve them when necessary. Protecting the privacy of NLS respondents entails considerable responsibilities for BLS, the organizations that conduct the surveys for BLS, and the researchers who use the data. Indeed, researchers in particular may become frustrated that they cannot obtain access to all the data that they want or that they must undergo a long review process at BLS to obtain some types of data. It is important to remember, however, that protecting respondent confidentiality must remain paramount. Any action that might jeopardize respondent confidentiality and erode the confidence of respondents could harm response rates in the NLS program and in other government or academic surveys. Thus, without the safeguards in place to protect respondent confidentiality, researchers would have far less data available to work with than they currently enjoy.

Contractors' Role in Maintaining Respondent Confidentiality. BLS, NORC, and CHRR are responsible for following the Federal requirements and maintaining their own security procedures. As mentioned earlier, all officers, employees, and agents of BLS are required to sign agreements stating that they will not disclose the identities of survey respondents to anyone who does not work on the NLS program and is therefore not legally authorized to have such information. Each contractor has in place procedures to ensure that the data are secure at each point in the survey process. (See the Data Handling section for more information.)

Survey Procedures

Like all contractor staff, field interviewers are agents of BLS and are required to sign the BLS agent agreement before working on the NLSY79. All interviewers also must undergo a background check when they are hired. Confidentiality is stressed during training and enforced at all times. Field interviewers receive specific instructions in their reference manuals to remind them of the appropriate procedures when locating or interacting with respondents or contacts.

At the end of each interview, interviewers ask respondents to provide information on family members, friends, or neighbors who can be contacted if the interviewers are unable to locate the sample member in a subsequent round of interviews. The interviewers then use those contacts to help in locating sample members who have moved. When contacting a sample member's relatives, friends, or neighbors about the sample member's whereabouts, interviewers never disclose the name of the survey they are conducting. They are instructed to maintain the confidentiality of any relative, friend, or neighbor who provides information about the sample member's whereabouts.

Answering machines can pose problems when interviewers are contacting sample members because it is difficult to confirm that the interviewer is calling a sample member's correct telephone number or that other household members will not hear the message. For those reasons, interviewers are instructed not to leave messages on answering machines.

When interviewers contact the appropriate household, they ask to speak with the sample member. Interviewers introduce themselves and state the purpose of the call by saying that they are from the National Opinion Research Center at the University of Chicago and are calling concerning a national survey. The name of the survey is not disclosed to anyone but the sample member.

Special Situations

The NLSY79 is a general population survey and includes a variety of sample members with special circumstances, such as incarcerated individuals, respondents in the military, other institutionalized persons, disabled persons, those with limited English proficiency, and so forth.

Incarcerated Respondents. Incarcerated respondents constitute the largest group requiring special accommodations. The first challenge with incarcerated respondents is contacting them to schedule an interview. NLS interviewers must contact the prison administration to arrange for an interview, but the interviewers cannot legally reveal to the prison administration that the prisoner previously had participated in the survey without first obtaining the written, informed consent of the prisoner to reveal that information (Note: Data were incomplete for 2004 due to confidentiality concerns regarding inmates' participation in the NLSY79. A protocol was established for round 22 of the NLSY79). 

The following steps are used for obtaining prisoners' consent:

1. Prisoners are first sent a letter reminding them about their previous participation in a NORC survey, but, in case the mail is monitored by prison staff, the letter does not name the survey or BLS so as not to reveal the prisoner's participation. The letter encourages the prisoner to participate in the upcoming round of the survey.  It explains that NORC staff needs to set up an interview through the prison administration but that NORC cannot tell the prison administration about the prisoner's participation without the prisoner's informed consent.  he letter then asks the prisoner to request a consent form by signing and dating an enclosed form letter and mailing it to NORC in a pre-addressed, postage-paid envelope. The letter reminds the prisoner that the mail at the institution may be monitored and explains that the consent form that NORC will send the prisoner will state the prisoner's name and the name of the survey. The letter emphasizes that, by returning the enclosed form letter, prison management or staff may learn that the prisoner is a participant in the survey.
2. If the prisoner chooses to send the form letter to NORC, NORC then sends the prisoner a cover letter and a consent form that names the specific survey.  The prisoner is asked to sign the consent form and mail it to NORC in a pre-addressed, postage-paid envelope. Once NORC has received the signed consent form, NORC staff can contact the prison to request permission to interview the prisoner and learn about any restrictions that the prison administration may impose.
3. If the prison administration permits an interview and a date and time have been scheduled for the interview, NORC mails another letter to the prisoner. This letter serves two purposes. First, it tells the prisoner when the interview will take place. Second, it informs the prisoner in writing that the interview very likely will be monitored by prison that it is important to tell the prisoner in writing.

Once all of these steps are complete, the prisoner finally can be interviewed, but the NLS program takes additional steps to minimize the risk that prisoners might reveal illegal or illicit behavior in the presence of prison staff during the course of the interview. 

As described later in this chapter, such sensitive questions are asked in the self-administered portions of the NLSY79. During these portions of the survey, the typical protocol for a respondent who is not incarcerated involves the interviewer turning the laptop computer around to enable the respondent to read the questions to him or herself and enter the answers directly into the laptop computer without the interviewer knowing the responses. (In fact, the interviewer does not even know which questions the respondent answered). In some relatively low-security correctional facilities, such as some county jails and halfway houses, this protocol still would be possible. In higher security facilities, the prison administrators would not permit the prisoner to touch the computer, so the questions either would have to be read to the respondent or skipped altogether.

NLS program staff have identified the questions that could be considered even moderately sensitive or risky for the prisoner to answer out loud. Given this examination of these questions, the NLS program has adopted the following protocol for administering sensitive questions to prisoners:

1. At the very beginning of the interview, the interviewer will indicate in the survey instrument whether a respondent is in a correctional facility of any kind and, if so, whether the facility permits the prisoner to touch the laptop and enter responses to the self-administered questions. For Federal prisons, the interviewer assumes that the prisoner is not permitted to touch the laptop.
2. If the facility permits the prisoner to enter responses to the self-administered questions directly into the laptop, then the full set of questions, including all of the sensitive questions, would be administered.
3. If the facility does not permit the prisoner to enter responses directly into the laptop, or if the interview is conducted over the telephone rather than in person, all survey questions will be asked orally by the interviewer, but the instrument is programmed to skip sensitive questions in which the prisoner might be asked about illegal or illicit behavior.

Military Respondents. NLSY79 respondents who are in the military tend to be very cooperative and willing to participate in the surveys, but it sometimes can be difficult to locate and contact them, particularly if they are stationed outside the United States. It sometimes is necessary to seek the help of military or civilian staff in the Department of Defense to locate and contact military respondents, but NLS program staff first must obtain the military member's written, informed consent to reveal to Department of Defense staff that he or she previously had participated in the survey and is willing to be contacted to participate in future rounds of the survey.

Respondents with Limited English Proficiency. Some respondents lack fluency in English and are more comfortable using another language. It is not possible to accommodate all of the different languages other than English that respondents might speak, but the NLSY79 historically has made special arrangements for respondents and their parents who speak Spanish, the most commonly spoken language other than English among respondents. NORC staff members translate advance letters and other informational materials into Spanish to enable respondents and the parents of minor respondents to provide their informed consent based on information that is written in the language that they understand best. Survey questionnaires also have been translated into Spanish to ensure that the surveys are administered consistently, an alternative much preferable to having Spanish-speaking interviewers translate the English-language questionnaire during the interview. The first 20 rounds of the NLSY79 included a Spanish version of the questionnaire, but, because the number of respondents who speak only Spanish has continued to decline, it no longer is cost-effective to continue programming a computerized Spanish questionnaire. For that reason, Spanish questionnaires are not used starting with round 21 (2004) of the NLSY79. Advance letters and other informational materials still are available in Spanish, however.

Sensitive Topics. The NLSY79 has included questions on income and assets, religion, relationships with parents and other family members, sexual experiences, abortion, drug and alcohol use, criminal activities, homelessness, runaway episodes, and other topics that are potentially sensitive for respondents to discuss. Respondents are advised at the start of the interview that they can choose not to answer any questions that they prefer not to answer. During training, interviewers undergo exercises to teach them how to allay the concerns of respondents about answering sensitive questions and encourage them to respond.  Interviewers are instructed not to coerce respondents into answering questions that they prefer not to answer, however.

All questions in the NLSY79 are read to the respondent by an interviewer. The respondent then provides an answer, and the interviewer records that answer on a laptop computer. For especially sensitive questions, some respondents might be reluctant to answer truthfully--or at all--if they have to tell an interviewer their answers, even though interviewers can face criminal and civil penalties if they disclose the respondents' identities or answers to anyone not authorized to receive that information.

Guidelines for E-mailing Sample Members. At the end of each interview, respondents are asked to provide information that will help interviewers contact them during subsequent rounds of the surveys. In addition to the information collected about relatives, friends, or neighbors, interviewers also obtain the e-mail addresses of sample members who have them. During round 20 of the NLSY79 (conducted during 2002), the NLS contractors began using e-mail as a means to contact a small number of sample members who were hard to reach by other means. The following guidelines were enacted to ensure confidentiality:

1. The name of the survey is not contained in the subject line or text of the e-mail message. Some respondents may share the use of an e-mail address with other household members, so the survey name is omitted from the message to prevent other household members from learning the specific name of the survey.
2. E-mail is sent from one main address. Field interviewers are not permitted to use their individual e-mail accounts to contact respondents.

Respondents Knowing Respondents. One feature of the sample design in the NLSY79 is that there often are multiple respondents within the same original household, either siblings or, occasionally, spouses. It obviously is not possible in these cases to prevent family members from knowing that a relative is in the survey sample, but interviewers take steps to ensure that each respondent's answers remain private and are not revealed to other family members.

Consent from NLSY79 Respondents. Respondents are able to review the confidentiality and consent information presented in the advance letter. The respondent gives verbal consent to participate at the beginning of the interview.

Data Handling

An important part of maintaining respondent confidentiality is the careful handling and storage of data. Steps taken by BLS, CHRR, and NORC to ensure the confidentiality of all respondents to the NLSY79 include maintaining secure networks, restricting access to geographic variables, and topcoding income and asset values.

Network Security. The data that are stored and handled at each NLSY79 organization's site are done so with maximum security in place.  During data collection, transmission, and storage, password protection and encryption are used to secure the data. Standard protocols for network security are followed at each organization's site. Detailed information about these arrangements is not provided to the public to prevent anyone from circumventing these safeguards.

Restricting Access to Geographic Information. Geographic information about NLSY79 respondents is available only to researchers who are designated agents of BLS. These researchers must agree in writing to adhere to the BLS confidentiality policy, and their projects must further the mission of BLS and the NLSY79 program to conduct sound, legitimate research in the social sciences. Applicants must provide a clear statement of their research methodology and objectives and explain how the geographic variables are necessary to meet those objectives. For more information about applying to use the restricted-use Geocode data is available on the BLS Restricted Data Access page.

Topcoding of Income and Asset Variables. Another step taken to ensure the confidentiality of NLSY79 respondents who have unusually high income and asset values is to "topcode" those values in NLSY79 data sets. Values that exceed a certain level are recoded so that they do not exceed the specified level. In each survey round, income and asset variables that include high values are identified for topcoding. For example, the wage and salary income variable usually is topcoded, but variables indicating the amount received from public assistance programs are not. Notes in the codebooks for topcoded income and asset variables provide more information about the exact calculations used to topcode each variable. For more information see the NLSY79 Documentation section.

References

Center for Human Resource Research. "Technical Sampling Report Addendum: Standard Errors and Deft Factors for Rounds IV through XIV." Columbus, OH: CHRR, The Ohio State University, 1994.

Frankel, M.R.; Williams, H.A.; and Spencer, B.D. Technical Sampling Report, National Longitudinal Survey of Labor Force Behavior. Chicago: NORC, University of Chicago, 1983.

Baker, Paula C.; Mott, Frank L.; Keck, Canada K.; and Quinlan, Stephen V. NLSY79 Child Handbook: A Guide to the 1986-1990 NLSY79 Child Data. Columbus, OH:  CHRR, The Ohio State University, 1993.

NORC. NLSY-National Longitudinal Survey of Labor Force Behavior Interviewer's Manual-Household Screening. Chicago: NORC, University of Chicago, 1978.

Olsen, Randall J. "The Effects of Computer Assisted Interviewing on Data Quality." Columbus, OH: CHRR, The Ohio State University, 1991.

• Household Interview Section for NLSY79 Round 29 Questionnaire

• Migration History and Family Background Section for NLSY79 Round 29 Questionnaire

• Marital History Section for NLSY79 Round 29 Questionnaire

• Military Section for NLSY79 Round 29 Questionnaire

• On Jobs Section for NLSY79 Round 29 Questionnaire

• Employer Supplement Section for NLSY79 Round 29 Questionnaire

• Business Ownership Section for NLSY79 Round 29 Questionnaire

• Business Match Section for NLSY79 Round 29 Questionnaire

• Gaps Section for NLSY79 Round 29 Questionnaire

• Training Section for NLSY79 Round 29 Questionnaire

• Spouse Labor Information Section for NLSY79 Round 29 Questionnaire

• Fertility Section for NLSY79 Round 29 Questionnaire

• Health Section for NLSY79 Round 29 Questionnaire

• Income, Recipiency, Debt, and Assets Section for NLSY79 Round 29 Questionnaire

• Interview End Section for NLSY79 Round 29 Questionnaire

• Locator Section for NLSY79 Round 29 Questionnaire

• Interview Remarks Section for NLSY79 Round 29 Questionnaire

• Household Interview Section for Round 28 Questionnaire

• Migration History Family Background Section for Round 28 Questionnaire

• Marital History Section for Round 28 Questionnaire

• Regular Schooling Section for Round 28 Questionnaire

• Military Section for Round 28 Questionnaire

• On Jobs Section for Round 28 Questionnaire

• Employer Supplement Section for Round 28 Questionnaire

• Business Ownership Section for Round 28 Questionnaire

• Business Match Section for Round 28 Questionnaire

• Gaps Section for Round 28 Questionnaire

• Training Section for Round 28 Questionnaire

• Spouse Labor Information Section for Round 28 Questionnaire

• Fertility Section for Round 28 Questionnaire

• Health Section for Round 28 Questionnaire

• Smoking and Alcohol Use Section for Round 28 Questionnaire

• Income and Recipiency Section for Round 28 Questionnaire

• Attitudes and Personality Section for Round 28 Questionnaire

• Retirement Expectations Section for Round 28 Questionnaire

• Wills Section for Round 28 Questionnaire

• Foreclosure Section for Round 28 Questionnaire

• Financial Literacy Section for Round 28 Questionnaire

• Interview End Section for Round 28 Questionnaire

• Locator Section for Round 28 Questionnaire

• Interviewer Remarks Section for Round 28 Questionnaire

• Household Interview

• Migration History and Family Background

• Marital History

• Regular Schooling

• Military

• On Jobs

• Employer Supplement

• Business Ownership

• Business Match

• Gaps

• Training

• Spouse Labor Information

• Fertility

• Child Care

• Health

• Income, Recipiency Debt and Assets

• Attitudes and Personality

• Retirement Expectations

• Wills

• Foreclosure

• Financial Literacy

• Interview End

• Locator

• Interviewer Remarks

• Interview Methods and Target Universe
• Interview Schedule and Fielding Periods

Interview Methods and Target Universe

During each survey round, NORC attempts to reach all youth within the active samples. No respondents have been routinely excluded from locating efforts with the exception of respondents who have died or, in a small number of cases, were judged to be extremely difficult. The permanent NLSY79 sample designated for interviewing during the 1979-84 interview years consisted of all civilian and military youth who were interviewed in the base year and who were alive at the survey date.

In 1985, when interviewing of the full military sample ceased, the total NLSY79 sample size dropped from 12,686 to 11,607. Retained for interviewing in post-1984 surveys were 201 military respondents randomly selected from the entire military sample of 1,280; the remaining 1,079 military respondents were eliminated from the sample. The 201 military members who were retained included (1) 51 cases that would have been selected as part of a random sample of youth including the military and (2) 150 additional cases selected to provide a sufficient number of original military sample members to avoid overly large sampling variability for the military sample. Beginning in 1991, the 1,643 members of the economically disadvantaged, nonblack/non-Hispanic supplemental sample were no longer interviewed. Unless otherwise noted, eligible sample sizes reported in NLS publications include deceased and difficult-to-field respondents but exclude those respondents dropped from the sample. Additional information on numbers and characteristics of noninterviewed respondents can be found in the Reasons for Noninterview section.

NLSY79 respondents reside in each of the 50 States and the District of Columbia, U.S. territories, and other countries. Prior to fielding, respondents receive a short, informative advance letter reminding him or her of the upcoming interview and confirming the respondent's current address and phone number. As of the 2006 round, all main youth respondents are instructed to call and set up an appointment for their interview.

Field staff locating efforts begin when there is no contact from respondents. Using locator sheets, interviewers at the local level are responsible for contacting all respondents in their caseloads and for tapping additional local resources (post offices, departments of motor vehicles and vital statistics, and so forth) to locate those respondents who have moved. If an interviewer is unsuccessful in locating a respondent, the case is transferred to the field manager who undertakes additional locating strategies.

In the event that such local-level efforts fail, the case is forwarded to NORC's locating shop where the complete files on each respondent can be accessed and used for additional locating efforts. Respondents who cannot be located are only a small percentage of the total not interviewed in a given survey year. (For more information about noninterviews, refer to the Reasons for Noninterview section.)

In addition to its comprehensive locating efforts, NORC makes every effort to convert initial respondent refusals to completed interviews. Uncooperative respondents receive "refusal conversion letters" and a wide array of materials designed to encourage continued participation in the survey. Extensive locating methods and a strong conversion strategy, combined with close monitoring of response rates for each of the subsamples of the NLSY79, have resulted in relatively high retention rates for a longitudinal panel of this duration. 

In early rounds, telephone contact to complete the survey occurred under certain circumstances, such as 1987 when funding restrictions limited in-person interviews, or in any year, when the respondent resided in a remote area or field staff determined that phone contact was the preferred method of interviewing a respondent. Through the years, respondents have become more dispersed or expressed a preference for phone interviews. In response the number of telephone interviews increased greatly beginning in 2002 and is now the main mode of interviewing. The percent of surveys conducted by telephone for each survey year are shown in Table 1.

In rare cases, interviews are conducted in whole or in part with a proxy, a person other than the respondent (for example, four in 1991, two in 1992). A variable, entitled 'Interview Conducted with Proxy Respondent,' is present in the data to identify these interviews. In order to conduct such an interview, individual approval must be obtained by the NORC central office and the circumstances documented.

A Spanish version of the NLSY79 is prepared and NORC employs bilingual, Spanish-speaking interviewers. During the 2014 interview, for example, 93 respondents requested a Spanish version of the questionnaire.

The average length of a personal interview is approximately one hour. The 1987 telephone interviews were completed within about 40 minutes, while the administration of the child assessments added approximately 45 minutes to the total survey administration time for each child. 

Until 1989, the NLSY79 was conducted using only paper-and-pencil interviews (PAPI). PAPI interviews were performed by interviewers filling in the relevant fields of large printed questionnaire booklets. While these booklets were inexpensive to produce, interviewers could make mistakes in following complicated skip patterns and filling in answers. Moreover, after all interviews were completed, additional office staff were needed to transcribe the information collected. Computer-assisted personal interviews (CAPI) were designed to eliminate many of these problems. With CAPI, interviewers take laptop computers into the field instead of questionnaire booklets. A computer program automatically selects the next question, prevents interviewers from entering illegal values, and warns interviewers about questionable answers. The computer also eliminates the need for data transcription except for specific items collected verbally and coded later.

While the majority of interviews in 1990 were collected using PAPI materials, a subset of one fourth of respondents was administered their survey using CAPI methods in order to test the viability and reliability of CAPI administration. Due to the success of these experiments, the NLSY79 interviews became fully CAPI administered beginning in 1993. Users interested in the results of these experiments should consult Olsen (1991).  

Interview Schedule and Fielding Periods

The original interview schedule, which called for yearly personal interviews with NLSY79 respondents, was retained from 1979 through 1986. In 1987, budget constraints dictated a limited phone interview rather than a personal interview. Personal interviews resumed with the 1988 round and continued yearly until 1994.  NLSY79 respondents have been interviewed in even-numbered years since 1994.

The initial NLSY79 interviews were conducted between late January and mid-August 1979. The next several interviews were fielded in the first six months of the year; more recently surveys have typically begun in winter and ended the following winter. Table 2 provides information on the fielding periods for NLSY79 respondents.

Note: There is no timing requirement that interviews take place on the same day/month from round to round. Thus, a respondent interviewed at the beginning of one field period and then interviewed at the latter end of the next field period would have more weeks between interviews than someone who was interviewed the same time both survey years. Also, some respondents, for various reasons, may miss multiple survey rounds before they are interviewed again. This means that the number of weeks since respondents' last interview can vary greatly. The LINT-DATE variables give the date last interviewed.

From 1979 until 1986, timing of the fielding period was designed to allow all respondents still in school to be interviewed before they left to take temporary summer jobs. Detailed information was collected for jobs held by respondents while they were in school. Since the youngest respondents in the survey were 23 years old in 1988, the shift in fielding periods after 1987 had a relatively small impact on information on jobs held while in school. An attempt was made during the initial survey years to keep the fielding period for an individual respondent approximately the same from year to year in order to assure that the time between interviews was approximately twelve months.

Researchers conducting analyses on topics where time periods are critical should carefully examine the reference period of the questions, the actual interview date, and the duration since the preceding interview.

• Household Interview

• Migration History and Family Background

• Marital History

• Regular Schooling

• Military

• On Jobs

• Employer Supplement

• Business Ownership

• Business Match

• Stock Options

• Gaps

• Training

• Philanthropy

• Spouse Labor Information

• Fertility

• Child Care

• Health

• Smoking and Alcohol Use

• Income, Recipiency and Debt

• Educational Expenditures

• Attitudes and Personality

• Risk

• Retirement Expectations

• Wills

• Foreclosure

• Financial Literacy

• Interview End

• Locator

• Interviewer Remarks

• Household Interview

• Migration History and Family Background

• Marital History

• Regular Schooling

• Military

• On Employers

• Employer Supplement

• Business Ownership

• Business Match

• Stock Options

• Gaps

• Training

• Philanthropy

• Spouse Labor Information

• Fertility

• Child Care

• Health

• Smoking and Alcohol Use

• Income and Assets

• Risk

• Retirement Expectations

• Wills

• Foreclosure

• Financial Literacy

• Interview End

• Locator

• Interviewer Remarks

• Household Interview

• Migration History and Family Background

• Marital History

• Regular Schooling

• Military

• On Employers

• Employer Supplement

• Business Ownership

• Stock Options

• Gaps

• Training

• Philanthropy

• Spouse Labor Information

• Fertility

• Child Care

• Health

• Smoking and Alcohol Use

• Income and Assets

• Risk

• Retirement Expectations

• Foreclosure

• Interview End

• Locator

• Interviewer Remarks