Technical Note The estimates in this release were obtained using data from the first 18 rounds of the National Longitudinal Survey of Youth 1997 (NLSY97). This survey is conducted by the Center for Human Resource Research at The Ohio State University and the National Opinion Research Center at the University of Chicago under the direction and sponsorship of the U.S. Department of Laborís Bureau of Labor Statistics. 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. This sample size is not adjusted for sample members who have died. Individuals were surveyed annually from 1997Ė2011 and biennially since 2011. In 2017-18, 6,734 individuals responded to the survey, for a retention rate of 75 percent (representing a 77 percent response rate among those sample members who are still living). Only these individuals are included in the estimates in this release. This release examines the period from respondentsí 18th birthday until their 33rd birthday. All results are weighted using the survey weights from the round in the year the respondents turned 33, with the exception of age 25 characteristics in Tables 1 and 6, which use survey weights at age 25. The survey weights correct for interview nonresponse and permanent attrition from the survey. 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 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 respondentís 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 respondentís 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 33 during calendar year 2017, whereas the oldest respondents (birth year 1980) turned 33 during calendar year 2013. Some respondents may not be used in all tables if information about their work history is incomplete. As with age, the education attainment of individuals may change from year to year. Educational attainment is taken at the time of the respondentsí 33rd 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 degree or any enrollment in college after high school are counted as having some college. Definitions 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. 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. Partner Status. Partner status is determined during the month the individual turned 33. Respondents who are married but not living with their spouses are counted as married. 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. Respondents who are not married and not cohabitating are counted as single. 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. The term Hispanic or Latino is considered to be an ethnicity group, and Hispanics or Latinos 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 ethnicity 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.