The adult outcomes have four domains with a total of 10 measures.
The health domain includes two measures: alcohol abuse or dependence around age 30; drug use (marijuana or cocaine) in the past month around age 30.
A series of questions, asked during the 1982-1985, 1988-89, 1992, and 1994 surveys, elicited information on the development of drinking patterns, quantity of various alcoholic beverage consumed, frequency of use, impact of consumption on schoolwork and/or job performance, and types of physiological and behavioral dependency symptoms. Although types and wording of alcohol abuse or dependence questions vary over the years, the items in the1989 and 1994 surveys are almost identical. We use 1989 data for those born in 1957-1960 and the 1994 data for those born in 1961-1964. The respondents were between ages 29-32 during these years. Diagnosis of current alcohol abuse and dependence were derived using a virtually identical set of 29 symptom-item questions in the1989 and 1994 surveys designed to operationalize the DSM-III-R abuse and dependence. The creation of the measure of alcohol abuse or dependence follows a set of complicated criteria provided by Harford, and Grant (1994). Alcohol abuse and alcohol dependence are different measures of alcohol problems. We combine them to form a single variable that takes the value of one if either condition is met.
Questions on substance use were included in the 1984, 1988, 1992, 1994, and 1998 surveys. Among other usage information collected, these surveys collected information on the most recent use of marijuana and cocaine, from which the measure of past-month drug use was created. The 1988 data were used for those born in 1957-1960 and the 1994 data were used for those born in 1961-1964. Respondents were ages 28-32 in these years. Past-month drug use measures whether a respondent used marijuana or cocaine in the past month. We chose not to use a measure of drug use in the past year, another common measure, in order to reduce the likelihood of measuring occasional recreational use. We implicitly assume that adults who used these drugs in the past month are more likely to be regular drug users.
The economic domain has six measures: ever under the poverty line between ages 25-29; number of years in poverty between the ages of 25-29; ever on welfare (AFDC/TANF or food stamps) between ages 21-33; number of years on welfare between ages 21-33; percent of employable time spent employed between the end of formal schooling and age 33; and age when found a "steady" job, i.e. working at least 2 years for a single employer since leaving formal schooling.
Variables have been created in the NLSY database for each survey year (1979-1998) that indicate whether or not a respondent's total family income for the past calendar year was above or below the poverty level for a given family size. Our two poverty variables were created based on these variables from 1979-1994. The interview frequency of the survey changed to biennial after 1994 and the poverty information was not available for the missing years. As a result, the oldest we could observe all individuals is age 29. We chose 25 as the starting age to avoid classifying respondents in college as in poverty. If a respondent was in poverty in any of the years when he/she was 25-29 years old, a value of "1" was assigned to the respondent for the measure of ever under the poverty line between ages 25-29; otherwise, a value of "0" was assigned.
The "income" section of each year's questionnaire collects information on amounts and time periods during which cash and non-cash benefits were received from various sources of public assistance. The universe and type of data collected varies across survey years. This report focuses on AFDC/TANF and food stamps, since they are the major components of public assistance and were consistently collected over all survey years. Unlike poverty, information on welfare was collected using event histories and therefore information is available for every year from 1978-1997 even if the survey was not fielded in some years. Similar to the poverty measures, if a respondent received AFDC and/or food stamps in any of the years when he/she was 21-33 years old, a value of "1" was assigned to the respondent for the measure of ever on welfare between ages 21-33; otherwise, a value of "0" was assigned. The measure of years on welfare between the ages of 21-33 sums the years on welfare between the ages of 21-33.
The other two economic measures (percent time employed and tenure) were created using both the NLSY79 main and Work History Files. The NLSY79 Work History File was constructed from work experience data collected during the main NLSY79 surveys. It provides a week-by-week longitudinal work record of each respondent from January 1, 1978 through the current survey date. Since continued education may take away time from working, to give every respondent a consistent starting point in counting his/her percent time employed and tenure, we created the measure of percent time employed and the measure of tenure from the end of formal schooling to the age of 33. The age at which a respondent ended his/her formal education was created using two sets of created variables that summarize each respondent's school enrollment status and highest grade completed as of May 1 of each survey year from the NLSY79 main file. 25
"Percent of time employed" for each respondent is calculated by the ratio of weeks employed over weeks in the labor force between the end of formal schooling and age 33. This measure is intended to measure attachment to the labor force. We chose to limit this measure to time in the labor force so as not to "penalize" women for childbearing. Although some individuals maintain an attachment to the labor force, they have difficulties maintaining a steady job. We define "steady job" as one lasting at lest two years. For a discussion of measuring the transition from school to work, see Pergamit (1995).
To calculate age when first reached two years of tenure after the end of formal schooling, we first calculated the age when started each job listed. Then the starting age was compared with age when formal schooling ended. If the job was started before formal schooling ended, then the starting point for the job was replaced by age when formal schooling ended. Tenure was calculated for each job listed by the difference between the starting and the ending point of each job. Age when first reached two years of tenure was obtained by choosing the minimum age at jobs where two years of tenure was reached. One limitation of this variable is that college graduates cannot achieve two years of tenure at as early ages as those with less education (see Table 6). Thus, they appear to do worse for this outcome. The impact on the analysis, however, is small since college graduates generally attain two years of tenure quickly with fewer such individuals in the right tail of the distribution.
The family formation domain has one measure, which is a measure of six combinations of marriage and fertility status at the age of 33. Marital status and fertility status at the age of 33 were first created separately.
A series of edited Supplemental Fertility File variables that reflects the beginning and ending dates of marriages was constructed for 1982 through 1998. This information is derived from the marriage section of the NLSY79 questionnaire. We used the information to create length of first marriage and assigned marital status at the age of 33. Marital status at the age of 33 has three categories: never married, married and stayed married, and married but divorced at the age of 33.
Beginning in 1982, every wave of the NLSY79 data release has included a created variable that tracks the age at which respondents first had a child. This information was used to create fertility status at the age of 33, that is, whether a respondent had a child by the age of 33.
The marital status variable and the fertility status variable were then combined to create a six-combination measure of marriage and fertility status at the age of 33. The categories of this measure are: never married without children, never married with children, married without children, married with children, married but divorced without children, and married but divorced with children.
The crime domain has one measure: ever been in jail by the age 33. NLSY79 respondents are followed and interviewed even when they enter an institution. Interviewers designate the "Type of Residence" which identifies those respondents who resided in jail at each interview date. This information was used to create a binary measure of ever being in jail by the age of 33. Since some jail terms will have occurred between interviews, this is an underestimate of the number of respondents who ever spent time in jail.