Chapter 1: Introduction

• 1.1 The National Longitudinal Survey of Youth 1979 (NLSY79)

• 1.2 The NLS

• 1.3 NLSY79 Samples

• 1.4 Multiple Respondent Households

• 1.5 NLSY79 Children

• 1.6 Special Data Collections

• 1.7 NLSY79 Data Sets

• 1.8 Organization of the Guide

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1.1 The National Longitudinal Survey of Youth 1979 (NLSY79)

The NLSY79 is a nationally representative sample of 12,686 young men and women who were 14-22 years old when they were first surveyed in 1979. These individuals are now in their late thirties to late forties, and have been personally interviewed for more than two decades. Since their first interview, many of the respondents have made the transitions from school to work, and from their parents’ homes to becoming parents and homeowners themselves. Data collected yearly from 1979 to 1994, and biennially from 1996 to the present, chronicle these changes and provide researchers an opportunity to study in great detail the experiences of a large group of young adults who can be considered representative of all American men and women born in the late 1950s and early 1960s and living in the U.S. in 1979.

The primary purpose of the NLSY79 is the collection of data on each respondent’s labor force experiences, labor market attachment, and investments in education and training. However, the actual content of the NLSY79 is much broader due to the interests of governmental agencies besides the Department of Labor. At several points throughout the survey, various agencies have funded special sets of questions. In addition to major funding, supportive funding has been provided by the U.S. Department of Health and Human Services, the National Institute on Aging, the National Institute on Alcohol Abuse and Alcoholism, the U.S. Department of Defense and the Armed Services, and the National Institute of Education. Examples of other topical areas include:

1. Military participation-Support from the Department of Defense and the Armed Services made possible the 1979-84 interviews of 1,280 youth enlisted in the military.

2. Vocational aptitude-The Armed Services Vocational Aptitude Battery (ASVAB), a study which was jointly sponsored by the Departments of Defense and Labor, was administered to the civilian and military youth samples in 1980.

3. High school performance-Beginning in 1979, a five-year cooperative effort of the National Center for Research in Vocational Education and The Ohio State University’s Center for Human Resource Research resulted in a survey of the high schools of civilian NLSY79 respondents and the collection of detailed transcript information on potential high school graduates.

4. Time-use-In 1981, the National Institute of Education sponsored a set of time-use questions.

5. Alcohol and substance use-Funding from the National Institute on Alcohol Abuse and Alcoholism and the National Institute on Drug Abuse has made possible multiple fieldings of expanded sets of alcohol and substance use questions.

6. Children's issues-Assessments of NLSY79 children, the development of the fertility and the child care components of the youth surveys, and a child school survey were made possible through funding from the National Institute of Child Health and Human Development.

7. Department of Justice-A self-report supplement to the 1980 survey collected data on the respondent's participation in and income from various delinquent and criminal activities.

This detailed guide is designed for researchers who are either working or planning to work with the National Longitudinal Survey of Youth 1979 (NLSY79). Users who are interested in a general overview of the NLS cohorts should refer to the BLS website at http://www.bls.gov/nls. Users may also wish to read recent issues of NLS News, a quarterly newsletter, available online at http://www.bls.gov/nls/nlsnews.htm. For those not familiar with the NLS, a brief overview of the NLSY79 and the other NLS cohorts follows.

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1.2 The NLS

The National Longitudinal Surveys (NLS) are a set of surveys sponsored by the Bureau of Labor Statistics (BLS), U.S. Department of Labor. These surveys have gathered information at multiple points in time on the labor market experiences of diverse groups of men and women. Each of the NLS samples consists of several thousand individuals, some of whom have been surveyed over several decades. The earliest NLS interviews began in 1966 under the original sponsorship of the Office of Manpower, Automation, and Training (now the Employment and Training Administration). These cohorts were chosen in an effort to understand specific issues pertaining to the U.S. labor market, such as retirement, the return of housewives to the labor force, and the school-to-work transition. Since that time, however, the content of the surveys has been expanded to provide useful information on an extremely broad range of topics.

The first four NLS cohorts (Older Men, Mature Women, Young Men, and Young Women) were selected in the mid-1960s because each faced important labor market decisions that were of special concern to policy makers. Although the initial plan called for only a 5-year period of interviewing, high retention rates and widespread research interest led investigators to continue the surveys. In 1977, a survey of all known NLS data users and the recommendations of a panel of experts convened by the Department of Labor resulted in two decisions. The first was to continue the surveys of the four Original Cohorts for an additional five years (as long as attrition did not become a problem). The second decision was to begin a new longitudinal study of a panel of young men and young women.

This new study was initiated to permit a replication of the analysis of the 1960s Young Men and Young Women cohorts and to assist in the evaluation of the expanded employment and training programs for youth legislated by the 1977 amendments to the Comprehensive Employment and Training Act (CETA). To these ends, in 1978 a national probability sample was drawn of young women and young men living in the United States and born between January 1, 1957 and December 31, 1964. This sample included an overrepresentation of blacks, Hispanics or Latinos, and economically disadvantaged non-black/non-Hispanics. With funding from the Department of Defense and the Armed Services, an additional group of young persons serving in the military was selected for interviewing. This sample of civilian and military youth, called the National Longitudinal Survey of Youth 1979 (NLSY79), was first interviewed in early 1979 and has been re-interviewed regularly since that date.

The Children of the NLSY79 survey, begun in 1986, further enhanced the NLS. With funding from the National Institute of Child Health and Human Development (NICHD) and a number of additional government agencies and private foundations, detailed information on the development of children born to NLSY79 women has supplemented the data on mothers and children collected during the regular youth surveys. During these biennial surveys, a battery of child cognitive, socio-emotional, and physiological assessments are administered to NLSY79 mothers and their children. In addition to these assessments, the Children of the NLSY79 are also asked a number of questions in an interview setting. In 1994, children age 15 and older, the “Young Adults,” first responded to a separate survey with questions similar to those asked of their mothers and a wide array of attitudinal and behavioral questions tailored to their age group.

With the aging of the NLSY79 cohort, another longitudinal cohort has been started. The National Longitudinal Survey of Youth 1997 (NLSY97) collects information on the circumstances that influence or are influenced by the labor market behaviors of youth ages 12–16 as of December 31, 1996. Data on the youths’ educational experiences, along with their family and community backgrounds, are also included in the survey. Documenting the transition from school to work, this survey is designed to be representative of the population born during the period 1980 to 1984.

Information on sample sizes, interview years, and the current survey status of each respondent group is presented in Table 1.2.1 below.

Table 1.2.1 The NLS: Survey Groups, Sample Sizes, Interview Years & Status

Administration of the NLSY79 Project. Responsibility for the administration of the NLS resides with the Bureau of Labor Statistics (BLS), an agency of the U.S. Department of Labor. These surveys are part of a longitudinal research program that includes in-house analyses and other special projects. The NLS program is housed within the Office of Employment and Unemployment Statistics at BLS.

BLS contracts with the Center for Human Resource Research (CHRR) at The Ohio State University and the National Opinion Research Center (NORC) at the University of Chicago to manage the NLS program, share in the design of the survey instruments, disseminate data, and interview respondents.

The project is assisted in its efforts by the NLS Technical Review Committee. Meeting twice each year, committee members provide recommendations regarding questionnaire design, additional survey topics, potential research uses, methodological issues, data distribution, and user services. The committee is multidisciplinary, reflecting the wide range of social scientists using NLS data.

For more information about the NLS program, go to http://www.bls.gov/nls or e-mail NLS_info@bls.gov.
 

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1.3 NLSY79 Samples

The NLSY79 sampling design enables researchers to analyze the experiences of groups such as women, Hispanics or Latinos, blacks, and the economically disadvantaged. The following three subsamples comprise the NLSY79:

1. (1) a cross-sectional sample of 6,111 respondents designed to be representative of the non-institutionalized civilian segment of young people living in the United States in 1979 and born between January 1, 1957, and December 31, 1964 (ages 14–21 as of December 31, 1978)

2. (2) a supplemental sample of 5,295 respondents designed to oversample civilian Hispanic or Latino, black, and economically disadvantaged non-black/non-Hispanic youth living in the United States during 1979 and born between January 1, 1957, and December 31, 1964

3. a sample of 1,280 respondents designed to represent the population born between January 1, 1957, and December 31, 1961 (ages 17–21 as of December 31, 1978), and who were enlisted in one of the four branches of the military as of September 30, 1978

Users can identify a respondent’s sample type by using variable R01736. With a few exceptions, all members of the cross-sectional sample have been eligible for interview during each NLSY79 survey. Funding constraints imposed limitations on the numbers of military and supplemental sample members who were eligible for interview after the 1984 and 1990 surveys, respectively. Following the 1984 interview, 1,079 members of the military subsample were no longer eligible for interview; 201 respondents randomly selected from the entire military subsample remained in the survey. Following the 1990 interview, none of the 1,643 members of the economically disadvantaged, non-black/non-Hispanic subsample were eligible for interview. Table 1.3.1 presents sample sizes for several survey years.

Table 1.3.1 NLSY79 Sample Size by Subsample, Race & Gender for Selected Years

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1.4 Multiple Respondent Households

The NLSY79 sample design selected as respondents individuals aged 14 to 21 as of December 31, 1978, who were connected to a surveyed household during 1978. Respondents interviewed in 1979 originated from 8,770 unique households; 2,862 households included more than one NLSY79 respondent.

The most common relationships between respondents living in multiple respondent households at the time the survey began were those of sibling or spouse (see Table 1.4.1). During the 1979 survey, 5,863 respondents were members of a household containing multiple interviewed siblings. More than 330 respondents were members of a household in which their spouse was also interviewed.

Table 1.4.1 Number of NLSY79 Civilian Respondents by Type of Household: 1979

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1.5 NLSY79 Children

The child sample began in 1986; the expanded mother-child data collection has occurred biennially since then. The child sample includes children born to female NLSY79 respondents. The number of children born to interviewed mothers has increased from 5,255 in 1986 to more than 8,000 in 2004. Interviews were completed during 2004 with 7,538 children (including young adult children), or 91 percent of children born to mothers interviewed in that survey round. Starting with the 1994 survey, the children are treated as two separate groups. The first includes children who were under age 15 (as of December 31 of the survey year). These children are directly assessed (i.e. completed one or more of the assessment instruments), and information about the child is obtained from the child’s mother. The second group comprises NLSY79 children who are at least 15 years of age by the end of the survey’s calendar year. These “young adults,” most of whom were assessed during earlier child surveys, are administered a separate NLSY79-style questionnaire, that gathers information on a wide range of topics.

Sample sizes for NLSY79 mothers and children across survey years are presented in Table 1.5.1. Important issues related to changes over time in the NLSY79 child and mother sample sizes are discussed in the NLSY79 Child and Young Adult Data Users Guide, NLSY79 Children 1992: Description and Evaluation, and the NLSY79 Child Handbook: A Guide to the 1986-1990 NLSY79 Child Data.

Table 1.5.1 NLSY79 Mother & Child Samples: 1979-2004 Surveys

The child sample interviewed during 2004 includes substantial numbers of Hispanic or Latino and black children and children from birth through their late twenties. While the majority of children in the sample had been under 10 years of age in all survey years through 1994, the 1996 survey saw the number of children in the initial sample who are 10 years or older become the majority for the first time in the survey’s history. By 2002, the number of young adult children exceeded the number of children under age 15. More than 2400 of these respondents were age 21 and older as of the end of the most recent survey. Table 1.5.2 presents, by select age ranges and race/ethnicity, the number of children across survey years for whom interviews were completed.

Table 1.5.2 NLSY79 Child Sample Sizes by Age & Race/Ethnicity: 1986-2004

The overall sample of children interviewed in 2004 represents a cross-section of children born to women who were 37–45 years of age in 2004. The large number of children born to female respondents range in age from birth to 31 years. It is estimated that the number of children in the sample represents a majority of the children to be born to this contemporary cohort of American women. When weighted, the number of children born to these women can be considered fully representative of children born to a nationally representative sample of women who were between the ages of 14 and 21 on December 31, 1978 and in the U.S. in 1979.

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1.6 Special Data Collections

The NLSY79 survey combines respondent interviews with round-specific household enumerations and a series of separately fielded administrative data collections.  Annual or biennial surveys collect information directly from NLSY79 sample members about their work, family, and other life course experiences.  Round-specific household enumerations describe the composition of the household unit and the characteristics of each household member on the date of the interview.  A set of administrative data collections has transcribed data related to NLSY79 sample members found in internal school records.  These separately fielded collections include:

1. School Characteristic Information provided by secondary school administrators during 1980 for the 1979 NLSY79 sample group. School characteristic data were collected during 1995 and 1996 from the primary and secondary schools attended by Children of the NLSY79.

2. School Transcripts, including coursework and attendance records. Transcripts were collected and coded during the early 1980s, with some amount of data available for 8,951 NLSY79 respondents. School record information was collected during 1995 and 1996 for Children of the NLSY79 who were five years of age and older.

3. Aptitude and Achievement Scores from standardized tests administered during a young person's schooling. Scores were transcribed from school records between 1980 and 1983 for NLSY79 respondents and during 1995 and 1996 for the Children of the NLSY79.

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1.7 NLSY79 Data Sets

While all NLSY79 public use data are currently available online, at a nominal charge, you may purchase the cross-cohort CD which contains the cumulative longitudinal record of each respondent from 1979 to the most recent interview date. In addition to the main NLSY79 data set, special data files also exist. Brief descriptions of the current releases of the NLSY79 appear in the following table. Subsequent data releases will be announced in NLS News, the quarterly NLS newsletter, which is available online at http://www.bls.gov/nls/.

The cross-cohort CD also includes the most recent data from the NLSY97 and the Original Cohorts. For more information on the contents of the cross-cohort CD consult the NLS  .

Table 1.7.1 NLSY79: Current Data Releases

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1.8 Organization of the Guide

The remainder of the guide is organized as follows:

Chapter 2 contains the technical information on the NLSY79. It includes information on sample sizes and retention rates, sampling design and fielding procedures, sample representativeness and attrition, and weighting and design effects.

Chapter 3 provides information on how NLS variables are collected, created, and arranged in the data files. This chapter details how users can access variables and explains the accompanying documentation.

Chapter 4 presents summary discussions of variable sets arranged alphabetically by topic. Persons interested in reviewing, for example, variables that contain information on a respondent’s labor market status or geographic residence should turn to the respective topical section with that name. Each topical section includes variable summaries, references to relevant survey instruments or documentation items, cautionary notes to users about inconsistencies in the data, and helpful hints on how to use the data.

Chapter 5 presents information and explanations of the different types of item nonresponse occurring in the NLSY79. It also outlines the significance of incidences of item nonresponse.

Appendices are the sixth section of the NLSY79 User’s Guide. These appendices contain a quick reference guide with useful NLS information, a glossary of NLSY79 terms, summaries of the content of the various topical NLSY79 areas of interest, and information on standard errors and design effects.