National Longitudinal Surveys of Youth 1979. The NLSY79 is a series of surveys with a nationally representative sample of 12,686 young men and women who were between the ages of 14 and 22 in 1979. Annual interviews were conducted from 1979 until 1994; since then, respondents have been interviewed every other year (1996, 1998, etc.).
Respondents were selected using a multistage, stratified national area probability sample of dwelling units and group quarters. Three independent probability samples were recruited:
- Cross-sectional sample of 6,111 people designed to be representative of the young adult population living in the United States at that time;
- Supplemental set of 5,295 people designed to oversample Latino, Black, and economically disadvantaged, non-Latino, non-Black youth; and
- A military sample of 1,280 people designed to represent the population born between January 1, 1957 and December 31, 1961, serving in the military as of September 30, 1978. Interviewing of the full military sample stopped in 1985.
Data for the NLSY79 have usually been collected using personal interviews, but telephone interviews have also been used and, in fact, are becoming more common. The NLS studies are primarily designed to study the transition of young people into the labor market. As a result, questions are typically asked about education, work, and training. Information is also collected on everyone living in the household of the initial respondent.
New topics have been frequently added to the NLS surveys. The National Institute on Alcohol Abuse and Alcoholism, together with the National Institute on Drug Abuse, for example, has added questions on alcohol and substance abuse on various NLS waves, while the National Institute of Education added a set of time-use questions to the 1981 survey.
In 1986, the NLS79 was further enhanced with a survey of children from the NLSY79 sample, funded by the National Institute of Child Health and Human Development (NICHD), along with a number of other government agencies and private foundations. These supplemental questions have collected information on the development of children born to NLSY79 women and, starting in 1994, a separate survey was administered to children age 15 or older.
National Longitudinal Surveys of Youth 1997. With the aging of the NLSY79 sample, a new cohort of young adults was selected in 1997 to participate in the NLSY97 survey. The NLSY97 sample consists of two independent national probability samples:
- Cross-sectional sample of 6,748 people between the ages of 12 and 17 in 1997 designed to be representative of the young adult population living in the United States at that time and
- Supplemental set of 2,236 people designed to oversample Latino and Black respondents.
Data are usually collected using in-person interviewers although, as with the NLSY79 study, telephone interviews are also conducted and are becoming more common over time.11 While much of the interview is conducted using a computer-assisted personal interview (CAPI) system, questions about particularly sensitive issues are asked using an audio computer-assisted self-interview (ACASI) procedure. While respondents are living with their parents or other legal guardian, many of the household questions are asked directly to the parents. When the initial respondent is living elsewhere, information is collected on everyone in the respondent's household. Followup surveys are conducted annually, although the gap between the initial survey and the second round turned out to be a little longer, approximately 18 months.
As with all of the NLS surveys, the primary purpose of the NLSY97 is to collect information on labor force experience, education, and the transition into the labor market. A number of additional questions have also been added, however, including a set of questions on crime and criminal activities sponsored by the U.S. Department of Justice, as well as development questions added by NICHD.
Prospects for Survey Enhancement. Although several longitudinal studies were initially thought to be able to provide information on knowledge gaps on homeless families, at least if they were enhanced, this review suggests that only the two latest NLS surveys — NLSY79 and NLSY97 — may be particularly good candidates. Of these two, the NLSY97 may offer the better opportunity. A major challenge with the NLSY79 cohort is that the primary respondents are moving out of the age when homelessness seems to be most likely to occur. As noted in Chapter 1, the risk of becoming homeless seems to be higher when people are in their mid to late-20s. Therefore, the NLSY79 sample would have been most likely to have experienced homelessness from the mid-1980s to early 1990s. By now, with the youngest members of the NLSY79 sample already 40 years old, this cohort may be too old to provide a good opportunity to examine homelessness, at least prospectively.
The NLSY79 sample does include a subsample of children born to initial study participants whose ages would make them more likely to be currently experiencing homelessness. Adding questions to the NLSY79 sample about their history of homelessness, as well as to the NLSY79 Children and Young Adult surveys about both their history and current incidence of homelessness would, therefore, provide a rare opportunity to examine the intergenerational effects and impact of homelessness. However, the smaller sample size of the children's sample (only children born to women in the NLSY79 sample are surveyed) makes this a less promising approach.
The NLSY97 sample provides the best opportunity to examine family homelessness prospectively, which could help answer questions about the factors that lead to people becoming homeless and factors that help predict exiting out of homelessness. The attrition rate for the NLSY97 sample has so far been fairly low, making it more likely to still include respondents whose families have been homeless or who are at risk of becoming homeless. For example, as of the last reported round of the NLSY97 surveys (Round 5), 88 percent of the initial sample had been interviewed. The primary reason for not conducting an interview has generally been because the respondent refused the interview rather than an inability to locate the respondent (65% of the nonresponses in Round 5 resulted from refusals).