Technical Note The estimates in this release were obtained using data from the first 15 rounds of the National Longitudinal Survey of Youth 1997 (NLSY97). The NLSY97 collects extensive information on labor market behavior and educational experiences. Information about respondents' families and communities also is obtained in the survey. This survey is conducted by the National Opinion Research Center at the University of Chicago and the Center for Human Resource Research at The Ohio State University, under the direction and sponsorship of the Bureau of Labor Statistics of the U.S. Department of Labor. Partial funding support for the survey has been provided by the Office of Juvenile Justice and Delinquency Prevention of the U.S. Department of Justice, the Office of Vocational and Adult Education of the U.S. Department of Education, the U.S. Department of Defense, the National Institute of Child Health and Human Development of the U.S. Department of Health and Human Services, and the National Science Foundation. Sample The National Longitudinal Survey of Youth 1997 is a nationally representative sample of 8,984 young men and women who were ages 12 to 16 on December 31, 1996. This sample is composed of the following groups: --A cross-sectional sample designed to represent the noninstitutionalized, civilian segment of young people living in the U.S. in 1997 and born between January 1, 1980, and December 31, 1984. --Supplemental samples of Hispanic or Latino and black youths living in the U.S. in 1997 and born between January 1, 1980, and December 31, 1984. The fifteenth round of annual interviews took place between October 2011 and May 2012. This release examines the period from respondents' 18th birthday until their 27th birthday. All results are weighted using the survey weights from the round in the year the respondents turned 27. The survey weights correct for oversampling of some demographic groups and nonresponse. When weighted, the data represent all people who were born in the years 1980 to 1984 and living in the U.S. in 1997. Not represented by the survey are U.S. immigrants who were born from 1980 to 1984 and moved to the U.S. after 1997. NLSY97 sample members remain eligible to be interviewed during military service or if they become incarcerated or institutionalized. Work history data The total number of jobs that people hold during their work life is an easy concept to understand but a difficult one to measure. Reliable estimates require a survey that interviews the same people over the course of their entire work life and also keeps track of all the jobs they ever held. The NLSY97 tracks the number of jobs that people have held, but the respondents in this survey are still young, and have many years of schooling and work life ahead of them. As the cohort continues to age, however, more complete information will become available. A unique feature of the NLSY97 is that it collects the beginning and ending dates of all jobs held by a respondent so that a longitudinal history can be constructed of each respondent's work experiences. The NLSY97 work history data provide a week-by-week work record of each respondent from January 1, 1994, through the most recent survey date. These data contain information on the respondent's labor force status each week, the usual hours worked per week at all jobs, and earnings for all jobs. If a respondent worked at more than one job in any week, hours and earnings are obtained for additional jobs. When a respondent who missed one or more consecutive survey rounds is interviewed again, he or she is asked to provide information about all time since the last interview. Interaction between time and age in a longitudinal survey Because the NLSY97 is a longitudinal survey, meaning the same people are surveyed over time, the ages of the respondents change with each survey round. It is important to keep in mind this inherent link between the calendar years and the ages of the respondents. The youngest respondents in the sample (birth year 1984) turned 27 during calendar year 2011, whereas the oldest respondents (birth year 1980) turned 27 during calendar year 2007. Some respondents may not be used in all tables if information about their work history is incomplete. Definitions Educational attainment. Educational attainment is taken at the time of the respondents' 27th birthday. If a respondent had not earned a high school diploma or General Educational Development (GED) credential, he or she is counted as a high school dropout. Individuals with an associate's degree or any enrollment in college after high school are counted as having some college. Employed. The NLSY97 collects employment histories for civilian jobs and military service. Respondents are classified as employed if they did any work during the specified time period as paid employees, as self-employed proprietors of their own businesses, as unpaid workers in a business owned by a member of their family, or if they were serving in the Armed Forces. Unemployed. Respondents are classified as unemployed if they did not work during the specified time period but reported that they looked for work or were on layoff from a job. No probing for intensity of job search is done. Not in the labor force. Respondents are classified as not in the labor force if they did not work or look for work during the specified time period. Job. A job is defined as a period of work with a particular employer. Jobs are therefore employer-based, not position-based. If a respondent indicates that he or she left a job but in a subsequent survey returned to the same job, it would not be counted as a new job. For self-employed workers, each new job is defined by the individuals themselves. Partner Status. Partner status is determined using the household roster during the interview in the year the respondent turned 27. To be marked as cohabitating, the respondent must be living with an individual of either gender for at least one month in a sexual relationship. Living with roommates or parents would not affect partner status. Children in the household. The presence of children in the household is determined using the household roster during the interview the year a respondent turned 27. Children must be related to either the respondent or the respondent's cohabitating partner. This includes biological, step, adopted, and foster children. Children of platonic roommates or other family members are not counted as children in the home. Race and ethnic groups. In this release, the findings are reported for non-Hispanic whites, non-Hispanic blacks, and Hispanics or Latinos. These groups are mutually exclusive but not exhaustive. Other groups, which are included in the overall totals, are not shown separately because their representation in the survey sample is not sufficiently large to provide statistically reliable estimates. In other BLS publications, estimates usually are published for whites, blacks, and Hispanics or Latinos, but these groups are not mutually exclusive. Hispanic or Latino is considered to be an ethnic group, and people in that group can be of any race. Most other BLS publications include estimates for Hispanics or Latinos in the white and black race groups in addition to the Hispanic or Latino ethnic group. Information in this release will be made available to sensory-impaired individuals upon request. Voice phone: (202) 691-5200; Federal Relay Service: (800) 877-8339.