1. The Older Men: 5,020 men ages 45-59 as of April 1, 1966, interviewed periodically during 1966-83 and in 1990
2. The Young Men: 5,225 men ages 14-24 as of April 1, 1966, interviewed periodically during 1966-81
3. The Mature Women: 5,083 women ages 30-44 as of April 1, 1967, interviewed periodically from 1967 to the present
4. TheYoung Women: 5,159 women ages 14-24 as of January 1, 1968, interviewed periodically from 1968 to the present

Each of these "Original Cohorts" includes an oversample of black U.S. residents to ensure sufficient representation of blacks for statistical analyses.

Two additional cohorts have been added to the NLS as these original groups aged:

1. The National Longitudinal Survey of Youth 1979 cohort (NLSY79): 12,686 men and women ages 14-21 as of December 31, 1978, interviewed beginning in 1979. This survey originally consisted of annual interviews of a cross-sectional sample; black, Hispanic, and economically disadvantaged non-black/non-Hispanic oversamples; and a sample of youths in the Armed Forces. Although the economically disadvantaged non-black/non-Hispanic oversample and most of the military sample members were dropped for funding reasons, the rest of the sample continues to be interviewed on a biennial basis.
2. The National Longitudinal Survey of Youth 1997 cohort (NLSY97): 8,984 men and women ages 12-16 as of December 31, 1996, interviewed annually since 1997. The cohort includes a cross-sectional sample and an oversample of black and Hispanic youths.

Finally, the National Institute of Child Health and Human Development (NICHD) and a number of private foundations provide funding for a further extension of the NLS. The Children of the NLSY79 surveys, conducted biennially since 1986, supplement the data on mothers and children collected during the regular NLSY79 interviews with detailed information on the development of children born to women in the NLSY79.

In addition to BLS and NICHD, the following organizations have provided funding for the NLS:

• U.S. Department of Defense and Armed Services
• U.S. Department of Education
• U.S. Department of Health and Human Services
• U.S. Department of Justice, Office of Juvenile Justice and Delinquency Prevention
• National Institute of Education
• National Institute on Aging
• National Institute on Alcohol Abuse and Alcoholism
• National Institute on Drug Abuse
• National School-to-Work Office
• Social Security Administration
• Women's Bureau and Pension and Welfare Benefits Administration, Department of Labor

Developing Computer Software and On-Line Documentation

Traditional paper-and-pencil interviews, used since the NLS project's inception, have been replaced with computer-assisted personal interviewing (CAPI) using software developed by the Center. Together with the National Opinion Research Center (NORC) at the University of Chicago, the Center conducted the first national controlled experiment investigating CAPI's impact on data quality. Since this initial experiment in 1989, over 500,000 interviews have been administered in the United States, Canada, and South America using the Center's CAPI software.

For the newest NLS survey, the NLSY97, the Center further extended the use of CAPI technology by including an audio computer-assisted self-interview to collect sensitive data. The respondents can choose to read the questionnaire from the computer screen or use earphones to listen to the questions as they appear on the screen. A replacement for the paper self-administered questionnaire, the audio version improves response quality by reducing entry errors, permitting more complex questionnaire design, and minimizing errors due to respondent literacy problems.

At CHRR, CAPI is viewed as more than a field technology. We see CAPI as an opportunity to more closely link the steps before and after the field effort with the actual collection of data. Our approach makes it possible for survey specialists to design, debug, and test a CAPI interview rather than relying on computer programmers. Because the discipline of CAPI produces high-quality data, labor-intensive efforts to edit and clean the data and to retrieve missing items are no longer necessary.

To assist users in accessing data from large longitudinal data sets, the Center's computing staff merged electronic documentation files with data from each cohort and developed PC-based search and retrieval software. This software allows users to easily peruse the variables present for a given cohort, select variables of interest, and create ASCII extract files. The data and documentation files for all surveys are available on CD-ROM.

The Center maintains an on-line annotated bibliography of NLS research. Currently, the NLS Bibliography contains over 3,500 summaries of NLS-based journal articles, working papers, and dissertations published over the last several decades. This bibliography can be accessed at www.nlsbibliography.org.


For More Information
To aid researchers in using the NLS data, a number of informational manuals describe the NLS program and the individual survey groups in detail. For details about the Center or the NLS program, or to request a specific document, contact:

NLS User Services
921 Chatham Lane Suite 100
Columbus, OH 43221
(614) 442-7366; Fax (614) 442-7FAX
usersvc@chrr.osu.edu