NLSY79

The 1984 survey included an extensive set of questions on substance use, gathering information about respondents' illicit and nonprescribed use of the following substances:

• Marijuana/Hashish
• Amphetamines
• Barbiturates
• Tranquilizers
• Psychedelics
• Cocaine
• Heroin
• Other Narcotics

For each substance, data were collected on:

• Lifetime use
• Age at first use
• Most recent use
• Frequency of use in the past 30 days

In addition, retrospective data on respondents' monthly use of marijuana from January 1979 through the 1984 survey date were gathered. The extent of respondents' prescribed use of three types of drugs (amphetamines, barbiturates, and tranquilizers) was also collected. Respondents who were working or in the military were asked whether, since the date of last interview or since their job/military duty began, they had used or "felt high" from one or more of these substances and how frequently they had used each on the job.

A special Drug Use Supplement was administered during the 1988, 1992, 1994, and 1998 surveys to collect information on age at first use of marijuana/hashish, crack, cocaine, and other drugs; lifetime use; most recent use; and use in the past 30 days. The 1992, 1994, and 1998 questionnaires also asked about respondents' use of prescribed and nonprescribed sedatives, tranquilizers, stimulants, and pain killers. Beginning in 1994, respondents were asked to directly enter their answers into a laptop computer.

Other drug use questions are found in (1) the 1988, 1990, 1992, and 1994-2018 fertility series, which included questions on use of marijuana or cocaine in the twelve-month period before first/second pregnancies (see the "Birth Record xxxx" areas of interest) and (2) the section of the 1980 survey, which gathered information on the frequency with which respondents were engaged during the past year in smoking/selling marijuana or other drugs (see the  Crime, Delinquency, & Arrest Records section of this guide).

The 1980 interview asked about delinquent or criminal activities during the previous twelve month period. Categories included:

• Skipping school
• Alcohol/marijuana use
• Vandalism
• Shoplifting
• Drug dealing
• Robbery
• Assault
• Gambling

The number of respondents reporting participation is summarized in Table 1 and Table 2 below.

Delinquency scales

Adapted from previously used self-report delinquency scales, this instrument was modified for the 1980 NLSY79 survey to accommodate the confidentiality issues raised by in-home administration. In addition, it used an expanded response scale to differentiate very highly delinquent youth from occasional participants. A second set of questions in the 1980 survey measured involvement with the criminal justice system by tallying the number of police contacts and recording the resulting criminal convictions and sentences (probation, incarceration) received.

Related variables collected during this and other survey years include:

• Questions on  school discipline problems, such as whether each NLSY79 respondent had ever been suspended or expelled from school and when/if the youth had returned to school (see the School Discipline section of this guide)
• The childhood residence section of the 1988 survey, which collected information on whether NLSY79 respondents had resided in a detention center/jail/prison during any of their first eighteen years of life (see the "Family Background" area of interest)
• A yearly created 'Type of Residence' variable that identifies those NLSY79 respondents who resided in jail at each interview date. Table 3 lists the number of respondents that were in jail or prison at time of interview for each round. Responses of "in jail" to questions within post-1988 Employer Supplements and the "Gaps Not Working" sections of the main questionnaires for the reason not looking for work when not employed can also be used to identify incarcerated respondents (see the "Between Job Gaps" and "Periods Not Working Within Job Tenure" areas of interest).

Three sets of cigarette use data are available for NLSY79 respondents:

1. 1984 survey
   Data collected included:
   • Age at first use
   • Most recent use
   • Number of cigarettes smoked in the past 30 days

2. 1992, 1994, 1998, 2008–2014, and 2018–2022 surveys
   Respondents provided information on:

   • Whether they had smoked at least 100 cigarettes in their lifetime
   • The number of cigarettes smoked per day
   • The time elapsed (in months/years) since they last smoked daily

   Note: Until 2014, these questions were asked of all respondents. They were discontinued in 2016 but reinstated for all respondents in 2018. Beginning in 2020, these questions became part of the Health at Age 60 module and have since been administered exclusively to specific birth cohorts in 2020 and subsequent survey years.

3. Pregnancy-related smoking (1983–1986, 1988, 1990, 1992, and 1994–2018 surveys)
   Female respondents were asked about:
   • Smoking in the 12 months prior to pregnancy
   • The number of cigarettes smoked during pregnancy

The NLSY79 health sections are organized into two distinct periods:

• 1979 to 1996: During this time, most questions addressed health concerns that limited or restricted the respondent's ability to work.
• 1998 and beyond: As respondents entered middle age, the Health section was expanded to establish a baseline profile of their overall health at ages 40, 50, and 60.

40-and-over Health Module

Beginning in 1998, because of the aging of the cohort, an extended health module was administered to respondents at the first interview after turning age 40 and general questions on physical activity and exercise were administered to all respondents. While the pre-1998 health questions provide a picture of the respondent's current health restrictions, they offer little insight into chronic health problems that will affect their labor force activity in the future. For example, a serious ailment that slowly develops over time will not be picked up by the regular health questions until the respondent actually drops out of the labor market. This extended health module was created to provide a baseline health profile of the respondent for examining the interrelationship of health and labor market activity in advance of the retirement years. Variables with CCR (Chronic Conditions Roster) in the title have been labeled with this acronym internally for consistent sorting.

To broaden the usefulness of the NLSY79 health data, this extended module, comprising four major parts, is not restricted to work-related health problems, and all questions are asked irrespective of the respondent's labor force status.

1. The first part of the 40-and-over module asks respondents to answer the Center for Epidemiological Studies Depression Scale (CES-D). The 1998 and 2000 surveys collected a reduced set of seven items from the original 20 item CES-D scale (the full 20-item scale was last administered in 1992). The number of items was increased to nine beginning in 2002.
2. The second part of the extended health profile asks respondents when they last saw a health care professional. These questions provide researchers with the date of the respondent's last physical exam and last visit to the doctor for any reason. Information on individuals who never visit a doctor is available as well. This subsection also gathers information about the health and life status of the NLSY79 respondents' biological parents. Questions which ask respondents about their parent's health are designed to improve researchers' understanding of hereditary health problems. Respondents are asked whether their biological parents are alive and if not, their parent's age at death and cause of death. Information is also gathered about any major health problems afflicting either parent.
3. The third section reproduces the SF-12 scale, a 12-question health survey designed by John Ware of the New England Medical Center Hospital. The SF-12 is designed to provide a measure of the respondents' mental and physical health irrespective of their proclivity to use formal health services. Detailed information on the SF-12 is available from QualityMetric. QualityMetric also provides researchers with software and algorithms to score the SF-12. For more information see Appendix 19.
4. The last section of the 40-and-over health module asks respondents if they suffer from an extensive list of health conditions. Respondents with certain major conditions, such as cancer, hypertension, or diabetes, are asked the date at which the condition was first diagnosed and other details relevant to the particular condition.

50-and-over Health Module

This module was included beginning in 2008. The module is administered to progressive two-year birth year cohorts in the survey year during which they would turn at least age 50. NLSY79 respondents were born in 1957-1964. In 2008, the module was administered to respondents born in 1957-1958. In 2010, the module was administered to those born in 1959-1960, and anyone who skipped the 2008 interview, and so on. The 50-and-over Health module contains many of the same questions as the 40-and-over Health module. Some questions provide a second decennial point of reference for general health information. Many others provide updates on previously reported conditions. Questions about diagnosis of skin cancer and other types of cancer, various heart disease-related conditions, and stroke are also asked.

50-and-over respondents are again administered the CES-D items and the SF-12 question series, as well as questions about the life and health status of their parents if they were reported living in the 40-and-over module. In addition, 50-and-over respondents are asked to update information on previously reported conditions such as hypertension/high blood pressure, arthritis, diabetes/high blood sugar, asthma and non-asthma breathing problems, depression, and other emotional/psychiatric problems.

The 50-and-over Health module also contains questions on diagnosis of osteoporosis and the use of special equipment needed to accomplish usual activities, as well as a scale of functionality and the respondent's sleep habits. Finally, respondents are asked for other information about their health that they would like to report.

60-and-over Health Module

This module was included beginning in 2018. Similar to the 50-and-over Health Module, the 60-and-over Health Module is administered to progressive two-year birth year cohorts in the survey year during which they turn at least age 60. NLSY79 respondents were born in 1957-1964. In 2018, the module was administered to respondents born in 1957-1958. In 2020, the module was administered to those born in 1959-1960, and anyone who skipped the 2018 interview, and so on. The 60-and-over Health module contains many questions similar to the 40-and-over and 50-and-over modules, providing a third decennial point of reference for general health information for many respondents. Updates on some previously reported conditions are also collected. Questions about diagnosis of skin cancer and other types of cancer, various heart disease-related conditions, and stroke are also asked. Questions about Alzheimer's and other dementia-related conditions are included in the module, as well.

60-and-over respondents are again administered the CES-D items and the SF-12 question series, as well as questions about the life and health status of their parents if they were reported living in the most recent health module administered to the respondent. In addition, 60-and-over respondents are asked to update information on previously reported conditions such as hypertension/high blood pressure, arthritis, diabetes/high blood sugar, asthma and non-asthma breathing problems, depression, and other emotional/psychiatric problems. The 60-and-over module also contains several other attitudinal scales, including the Satisfaction With Life Scale/SWLS (Deiner, et. al.) and General Anxiety Disorder/GAD scale (Spitzer, et. al.). In 2018, four items on the Brief Resilience Scale/BRS (Smith, et. al.) were administered. Although the BRS questions were intended to be fielded again in 2020, they were discontinued partway through the survey round due to time constraints. A portion of the BRS data collected in 2020 is available in the public release.

The 60-and-over Health module also contains questions on the diagnosis of osteoporosis and the use of special equipment needed to accomplish usual activities, as well as a scale of functionality and the respondent's sleep habits. Finally, respondents are asked for other information about their health that they would like to report.

General health

Questions about general health practices and visits to health care professionals have been asked of respondents since the 2002 interview. Respondents are asked about levels and frequency of activity, whether they have had routine tests, whether they have discussed general health issues with their doctors, if they take certain kinds of medications, and usual eating habits.

Respondent characteristics

Height and weight

A respondent's height and weight are natural indicators of health. Height questions were asked in 1981, 1982, 1983 (only to females who were ever pregnant), 1985, and 2006-2016. Exercise caution because the height questions have been collected in a variety of formats. The 1981 question combines feet and inches into a single number. Hence, respondents range from 400 (four feet and zero inches) to 611 (six feet and eleven inches). The 1982 and 1985 questions convert all answers into just inches. The 1983 height questions are found under two different reference numbers: female height in feet is provided in R09989., while height in inches is provided in R09990. 

Since weight fluctuates more than height, questions on weight are asked more frequently. Weight questions appear in the 1981, 1982, 1985, 1986, 1988-90, and 1992-2016 surveys. Weight in all years is recorded in pounds. The weight data are normally distributed from 50 to 400 pounds in all years except 1989. In 1989, there are 11 individuals marked as weighing 996 pounds. This number is not a true weight but rather an out-of-range code. Users are advised to examine height and weight distributions prior to analysis in order to make informed decisions as to how to handle outliers.

Hair and eye color

Respondent hair and eye colors were collected during the 1985 interview and information on whether they were left or right handed was collected in the 1993 interview.

Asthma

In 2004 a series of questions about asthma were added to the survey. These included the onset and diagnosis of asthma, whether the respondent missed work, when they had an attack and methods of prescribed treatment. Also included were questions regarding onset in the children of female respondents. A reduced set of asthma questions were included beginning with the 2006 survey.

Heart medication

Beginning in 2008 respondents were asked if they were taking any statin drugs or heart medications.

Childhood health

In 2012, all respondents were asked a series of new questions on childhood health including overall health, major hospitalizations, or long periods of home recovery. Adversity questions included family mental health, alcohol abuse, physical abuse, and amount of parental affection. Researchers believe that questions such as these are predictive of adult obesity and other health-related outcomes. This question series was asked in 2014 or 2016 for those who were not interviewed in 2012.

Head injury

Also introduced in 2012 was a module on traumatic head injury. All respondents were asked if they have experienced a serious head injury or loss of smell. Because traumatic head injury and loss of smell have been found in numerous studies to be linked to subsequent dementia, these questions were added to augment ongoing efforts to track respondents' cognitive function as they advance into middle age and beyond. This module was repeated in 2014 or 2016 for those not interviewed in 2012.

Information on familial history of alcohol abuse or dependency was collected during the 1988 survey and included a series of questions on whether relatives of the respondent had been alcoholics or problem drinkers, the relationship of the respondent to up to seven such alcoholic relatives, and the length of time, if any, that the respondent resided with each such relative. Tables 1-4 summarize the alcohol use variables collected for the NLSY79 and the survey years during which each type of variable was collected.

There is considerable variation in both the quantity and type as well as the wording of alcohol use questions. The 1989 questionnaire, for example, combined the typically asked 'drinking ever interfered with schoolwork or job' questions into a single 'kept drinking even though caused problems with work/home/school' question but expanded the number of questions dealing with the impact of alcohol use on other aspects of the respondent's life (such as personal relationships, health, participation in outside interests and activities). Many of the NLSY79 alcohol use questions have been adapted from those asked in the National Health Interview Surveys conducted by the U.S. Census Bureau.

Additional alcohol use variables

Two additional sets of alcohol use variables, not included in the tables, have been collected for select NLSY79 respondents:

1. Alcohol use during pregnancy
   Female respondents provided information on alcohol use during pregnancy in the 1983–1986, 1988, 1990, 1992, and 1994–2018 surveys.
2. Underage alcohol consumption
   The 1980 illegal activities supplement included a question for underage respondents about the number of times they had consumed alcoholic beverages without their parents' permission.

The Income and Assets section of each survey collected information on whether the respondent or their spouse received income from other (unspecified) sources, such as Social Security, pensions, or annuities. This data includes details about the types of pension or retirement plans, their value, withdrawals or repayments, and other related information. Follow-up questions inquired whether:

• An opposite-sex adult/partner (1979-1984, 1990-2022) had received Social Security/Railroad Retirement or pension income in the past calendar year
• Household income was received by those respondents living in their parental home or by any other household member related to these respondents from:
  • Governmental or private pensions or annuities
  • Social Security/Railroad Retirement benefits was collected during the 1979-1986 household interviews.

Disability payments

Fielded during the 1980-2022 surveys are questions to determine whether the respondent or their spouse—and beginning in 1994, their "partner," if applicable—had received income in the past year from veterans' benefits, Workers' Compensation, or other disability sources. If income was reported, the amount was recorded. These data can be found in the NLS Investigator by searching for question names starting with Q13-70 and DISABILITY.

1994 changes

Beginning in 1994, the Employer Supplement section on benefits was expanded to include a large amount of pension information. The pension questions are asked for each job that a respondent works at 20 hours a week or more. The pension section elicits information from the respondent on the following 11 subjects:

1. If eligible for a plan
2. How many participating in
3. How many plans eligible for with each employer
4. Knowledge of each plan
5. Number of years enrolled in a plan
6. Type of plan
7. Employer contributions
8. Employee contributions
9. Whether choice in investment strategy
10. How much the plan is worth
11. Investment strategy

Retirement savings

Additionally, in 1994-2004, 2008, 2012, 2016, and 2020, a series of four questions was incorporated into the Asset section of the questionnaire to track retirement savings. Prior to 1994 this information was asked for as part of the answers to other asset questions, while in 1994 pension questions were separated out. The first question asks if the respondent/spouse has any IRA accounts. If the answer is yes, respondents are queried about how much money is held in their IRA. Then the respondent is asked if they or their spouse or partner hold any 401k or 403b accounts. If the answer is yes, they are questioned how much money is held in these accounts.

Respondent (FA_6E_):

• TOTAL VALUE OF EMP-SPONSORED RETIRE PLANS (TRUNC)
• VALUE OF EMPLOYER-SPONSORED RETIREMENT PLANS IN XXXX MORE THAN ENTRY AMOUNT 
• VALUE OF EMPLOYER-SPONSORED RETIREMENT PLANS IN XXXX MORE THAN $5K
• VALUE OF EMPLOYER-SPONSORED RETIREMENT PLANS IN XXXX MORE THAN $30K

Spouse/Partner (FA_7C_):

• TOT BALANCE OF SPAR-EMP SPONSORED RETIRE PLANS (TRUNC)
• TOT AMT OF SPAR EMPLOYER-SPONSORED RETIREMENT PLANS MORE THAN ENTRY AMOUNT 
• TOT AMT OF SPAR EMPLOYER-SPONSORED RETIREMENT PLANS MORE THAN $5K
• TOT AMT OF SPAR EMPLOYER-SPONSORED RETIREMENT PLANS MORE THAN $30K

In 2004, questions were added for younger workers about hypothetical changes to the Social Security program and the introduction of personal retirement accounts (SOCSEC-).

• CURRENT SOCIAL SECURITY PROGRAM OR REPLACE PART OF SOCIAL SECURITY WITH A PERSONAL RETIREMENT 
• PERSONAL ACCOUNT INVESTMENTS - STOCKS 
• PERSONAL ACCOUNT INVESTMENTS - PRIVATE BONDS 
• PERSONAL ACCOUNT INVESTMENTS - GOVERNMENT BONDS 
• ANY TYPE OF PERSONAL INVESTMENTS CHOSEN 
• PERCENTAGE OF PERSONAL RETIREMENT ACCOUNT MONEY PUT INTO EACH INVESTMENT 
• PERSONAL RETIREMENT ACCOUNT - LUMP SUM OR MONTHLY PAYMENT OPTION?

In 2010, a series of questions about stock options (STOCK_OPTIONS_) was administered. In 2012 and 2014, these questions were asked only to respondents who had not been asked them in 2010 (round 24).

• OFFERED ANY STOCK OPTIONS BY R EMPLOYER
• OFFERED A STOCK OPTION MORE THAN ONCE BY R EMPLOYER
• R EXPECTS TO BE OFFERED A STOCK OPTION

Researchers interested in the income of a respondent's spouse or partner are cautioned that, until 1994, the survey contained separate sets of questions for spouses and partners. This means that researchers who are trying to compute the couple's income need to check answers to both spouse wages and partner wages. After 1994, the CAPI questionnaire combined these sets of questions into one. Hence, users not wanting partner's income data should examine the wording of income source questions carefully. Partner income and earnings are not included in the constructed "Net Family Income" variable.

The NLSY79 cohort is a unique source of income information. Because the original NLSY79 panel contained a supplemental sample of 5,295 economically disadvantaged, nonblack/non-Hispanic youths, researchers are able to precisely measure income of low-income and minority households. Moreover, because in-depth income questions have been asked since 1979, detailed age/income profiles can be traced over time.

Most NLSY79 income questions refer to the previous calendar year. For example, if the survey is being fielded in 1992, most questions ask the respondent to report how much they earned during the 1991 calendar year. A summary of the questions asked in the early surveys is shown in Tables 1 and 2. During each of the first four surveys (1979-1982) NLSY79 respondents were examined to see if they met one of following five criteria:

1. 18 years old or greater
2. Had a child
3. Enrolled in college
4. Married
5. Living outside their parents' home

If they did not meet any of these five criteria, respondents were asked the simple income section outlined in Table 1. However, if respondents fell into one of these five categories, the interviewer asked a more detailed set of questions outlined in Table 2.

In the 2018 survey year, the income section went through some re-designing. Question-level changes were made; however, the primary goal of these changes was not to collect new information but to be more efficient in collecting detailed information for the same categories asked about in previous rounds.

Beginning in 1983, the NLSY79 questionnaire used the same set of income questions for all respondents, since all respondents would have been at least 18 years old and thus sent through the long series of questions. In this set of questions, all respondents are asked about income from a variety of sources, as shown in Table 3. First, they report how much money they received from working; questions are asked about their military income, wages, salaries, tips, farm income, and business income. Then, respondents provide information about transfers from the government through programs such as unemployment compensation, AFDC (before 1996) and TANF payments, Food Stamps, SSI, and other welfare payments. Respondents are then queried about transfers from nongovernment sources such as child support, alimony, and parental payments. Finally, respondents report income from other sources such as scholarships, V.A. benefits, interest, dividends, and rent.

Nonresponse

One major concern when asking individuals about their income holdings is nonresponse bias. While it is outside the scope of this section to fully investigate nonresponse bias in the NLSY79, this section briefly describes nonresponse in 1992 as an example. Researchers interested in a fuller discussion of nonresponse should consult the Item Nonresponse section of this guide. There are two primary types of questions on income: general questions asking whether the respondent received income from a particular source and specific questions on the amount of income. Factors that are likely to contribute to nonresponse are suspicion, uncertainty, shared responsibility for family finances, and complex financial arrangements.

Table 4 provides information on response rates to income questions in 1992. The table is divided into three sections. The first section shows the response rates for questions asked about the respondent. The second and third sections show the response rates for the spouse and partner, respectively. The average response rates (99.9 percent) in the receipt column show that almost every NLSY79 respondent will tell the interviewer if they received income from a particular source. Additionally, the amount column, which is calculated based only on individuals who received a particular type of income, also shows high response rates. Except for alimony payments (54 percent), more than 90 percent of all NLSY79 respondents knew and were willing to divulge how much they earned from various sources.

Examining the sections labeled "Spouse's Income" and "Partner's Income" shows a very different picture. Spouse's income is known with less certainty and partner's income with much less certainty than the respondent's income. For example, 91.9 percent of the respondents reported how much they earned from their own business or farm. However, these same individuals were able to report only 85.6 percent of the earnings of spouses and only 59.7 percent of their partner's income from the same source.

Financial questions

Financial questions often elicit from respondents either a "refusal" or a "don't know" response. From 1979 to 2000 the NLSY79 interviewers faced with a "refusal" or a "don't know" simply went on to the next question. Starting in 2002 the NLSY79 began handling these cases of item non-response three different ways. Some respondents were asked: 

for a range of values

• The range of values questions gives respondents a method of providing a lower and upper bound answer. Examining the data suggest that some respondents give quite precise bounds. When a respondent gives a range, researchers should note that the upper and lower bound variables are not always in the correct order. The survey always asks for the upper bound first and the lower bound second. However, if a respondent gives the smaller number first, that number will be typed into the upper bound variable and the range values will be reversed.

if they could provide an answer within $10,000

• Within $10,000 is designed to tell the respondent that a rough figure is an acceptable answer. Extreme precision is not needed for these answers.

simple above or below questions which bracketed the true value

• Bracketing lets respondents answer if the amount is above or below a particular value. These initial values are called the variable's entry point. The list of all entry points used by the NLSY79 survey in 2002 and 2004 is found in table 5 and for 2006-2016 in table 6. For example, the entry point for the person's vehicle is $20,000. If the answer to the entry point question is neither a refusal nor a don't know then the respondent is asked one more "is the value above or below question." This results in a series of four brackets that provide researchers with a rough idea the range the item's value falls into. One caution for researchers is that the entry point value is quite low for certain categories. For example, homeowners who do not know the value of their primary residence were asked if it was above or below $20,000. This low entry point value resulted in large number of cases all falling into the same unfolding bracket. An additional caution is that while three of the brackets have a defined range, the top range is open-ended.

Example: An example of how item non-response to financial questions is handled is seen in the questions that ask about income from the military in the 2002 survey. Question Q13-16_TRUNC asks respondents "About how much total income did {spouse name}receive during 2001 from the military before taxes and other deductions?" If the respondent is unable to provide a specific amount the survey in 2002 decides which of the three alternative methods will be used in question Q13-16_EXP.

In question Q13-16_E~000001 some interviewers probe for the answer by asking if they could provide "an approximate range for that amount?" If the respondent can provide a range both the upper and lower number is captured. In question Q13-16_D some interviewers asked "To the nearest $10,000, can you tell me about how much your spouse or partner received during 2001, from the military before taxes and other deductions?"

In question Q13-16_A some interviewers asked "Would it amount to [entry pt military inc] or more?" Looking at Table 5 shows that "entry pt military inc" has the value of either $15,000 or $30,000. This results in the interviewer asking if the income was more or less than these amounts. If the respondent states less than $15,000 or $30,000 they are asked one last question "would it amount to $5,000 or more." If the respondent states more than $15,000 or $30,000 they are asked "would it amount to $40,000 or more."

These questions result in the researcher being able to classify respondents who do not know the military pay received by their spouse into four groups; $0 to $5,000, $5,000 to $15,000/$30,000, $15,000/$30,000 to $40,000 and over $40,000. The specific entry points and symbol names for all income and asset questions used in the bracketing questions are found in Tables 5 and 6.

Entry amount selection

Respondents were randomly assigned to get one of the three methods (unfolding bracket, nearest $10k, range) discussed above when they stated don't know or refused in an income question. Additionally, among respondents who were given unfolding brackets, some respondents are given relatively high starting points (called in some of the codebook pages "the 60 Percent group") or relatively low starting points (called "the 40 percent group"). In 2002, researchers interested in knowing which type of question a respondent was selected to receive should look at question HH_INC_3_EXP, which has the title "Type of question R assigned for household interview income recall experiment."

In later years, like 2008, there is no specific question available that marks if the respondent gets a low or high entry point. Researchers can determine if a respondent is in the low or high group by looking at one of the entry symbols. For example, the public assistance and welfare entry question has the question name "symbol_entry_asst." Respondents who have a $5,000 value for symbol_entry_asst are part of the low entry amount group, while respondents who have a $7,000 value for this item are part of the high entry amount group (see Table 6).

Topcoding

Because the NLSY79 is a public use data set distributed widely throughout the research and public policy communities, the survey takes extensive measures to protect the confidentiality of respondents. One method of ensuring confidentiality is to "top code" unusually high income values. The NLSY79 top code values were originally designed to prevent identification of the top two percent of respondents.

The NLSY79 has used four top coding algorithms for income:

1. From 1979 to 1984, every NLSY79 income question that elicited a response above $75,000 was truncated to $75,001.
2. From 1985 to 1988, the values were increased to $100,000 and $100,001 respectively. Unfortunately, this algorithm results in a sharp downward bias in the mean value of NLSY79 income holdings since the entire right hand tail is truncated. 
3. To fix this problem, a new algorithm was introduced beginning in 1989. The new top code algorithm replaced all values above the cutoff with the average of all outlying values.
4. Beginning in 1996, another new algorithm was used. This algorithm takes the top two percent of respondents with valid values and averages them. That averaged value replaces the values for all cases in the top range. 

Top coding primarily affects seven of the NLSY79 income variables:

1. the income from respondent's wages
2. respondent's business
3. spouse's wages
4. spouse's business
5. partner's wages
6. rest of the family
7. and other sources such as rents, interest, and dividends

Income values reported in the 2022 survey have been topcoded using an updated set of decision rules. These rules were formulated based on the two percent method described above, with some modifications for the treatment of extreme outliers and very low frequency variables.

Respondents living abroad

Living outside the U.S. does not preclude a respondent from being interviewed. For example, in 1992, 125 respondents lived abroad. Between 1989 and 1992, for people who hold assets denominated in foreign currency, little effort was made to transform these assets into dollar figures. Instead, such values are classified as "invalid skips" in the data. Beginning in 1993, an effort was made to convert these currencies whenever the unit in which the response was made could be determined. While researchers are warned that this occurs, relatively few individuals live outside the U.S. Based on analysis of comments and data in the 2022 survey data, reported income values have been treated as U.S. dollars unless a foreign currency is specifically identified by the respondent.

Risk preference

In 2010, a set of questions on risk preference was administered that included three questions from 1993, 2002, and 2006 and several new questions adopted from the German Socio-Economic Panel Study. In 2012 and in 2014 the questions were asked only of respondents who were not interviewed in 2010.

Family poverty status variables are available for NLSY79 respondents. In addition, detailed information is provided on public assistance income sources, and a series of environmental variables describe the extent of family and individual poverty within the respondent's geographical area of residence. Family income information collected during the 1978 screening was used to designate the economically disadvantaged oversample of NLSY79 respondents.

Family poverty status

Variables have been created for each survey year that indicate whether a respondent's total family income for the past calendar year was above or below the poverty level. Information used to create the 1979-2022 poverty variables is derived from either:

1. the total family income information provided during the household interview by the parent when the respondent was living in the parental home or
2. the sum of component income sources reported by the respondent (when not living in the parental home) during administration of the "Income" section of each questionnaire. 

Income sources for the respondent and all persons related to them by blood, marriage, or adoption are included in the calculation. Availability of data for individual respondents has been affected by nonresponse to the income questions. Poverty status data are not available for those respondents who, during post-1986 survey years, had one or more income components missing. Nor are they available for those respondents who, during the 1980-1986 interviews, were "refusals" or "don't knows" to both the household interview dollar amount question and a follow-up question requiring a "yes-no" response to a question on level of family income. The method used to create the 1978 family poverty status variable was unique. Appendix 2: Total Net Family Income in the NLSY79 Codebook Supplement provides a narrative description; R02179.30 identifies which of three income sources was used to determine each respondent's status.

Two sets of poverty level indicators have been used across survey years:

• The yearly poverty income guidelines, issued by the U.S. Department of Health and Human Services and based on Census Bureau poverty thresholds, were used to determine poverty status for the 1978, 1979, and 1987 through recent survey years.
• Projected poverty income levels computed by CHRR were used for the 1980-1986 poverty status variables. More complete information on the calculation procedures developed by CHRR to create 'Total Net Family Income' and 'Family Poverty Status' and to project poverty guidelines for the 1980-1986 survey years can be found in Appendix 2: Total Net Family Income in the NLSY79 Codebook Supplement. Copies of the official poverty guidelines and the projected 1980-1986 cutoff values are included in the appendix.

Public assistance support sources

The Income and Health sections of each year's questionnaire collect information on amounts and time periods during which cash and noncash benefits were received from such sources as public assistance, Supplemental Security Income (SSI), Aid to Families with Dependent Children (AFDC), Temporary Assistance for Needy Families (TANF), Food Stamps, government rent subsidies, public housing, or welfare-provided health/hospitalization coverage. Beginning with the 2018 interview, respondents were asked to differentiate SSI and Social Security Disability Insurance (SSDI) if possible. The universes and types of data collected vary across survey years as indicated in Table 1.

Poverty characteristics of respondent's county (1979-2004)/SMSA of residence (1979-1982)

Based on data from the 1977, 1983, 1988, 1992, and 1996 County & City Data Books, variables such as percent of families with money income below the poverty level, number of persons below the poverty level, and families with female heads of household below the poverty level are available for each respondent's area of residence in the restricted-use Geocode file. The geographical area (county or SMSA) for which these data are available varies across survey years.

Value of Food Stamps (SNAP)

The created variable 'Total Net Family Income,' used to determine a respondent's poverty status, includes in its calculation the noncash value of Food Stamps. In 1987, a 'Total Net Family Income in Past Calendar Year (Census)' variable was created by CHRR that excluded food stamp income for the 1986 calendar year only. Census poverty calculations for the U.S. do not include the value of food stamps. Hence, NLSY79 income calculations are similar, but not exactly the same as, other national data sets.

Welfare reform questions in 1996

In 1996, an additional set of questions was included to solicit information on the effects of welfare reform on certain behaviors of respondents related to seeking assistance. Respondents reporting AFDC or SSI/Other Public Assistance were asked whether they had sought work, enrolled in training/school, or performed community service in response to changing requirements. 

Respondents not reporting these types of assistance, but reporting a combined R and spouse/partner income of 125 percent of the poverty level or less, were asked whether they had applied for assistance, why they had not received any, and if and how the welfare reform changes affected them. (The determination of poverty level for the purpose of conducting the survey was based on the number of household members. This may be a relatively crude measure of family size, but should result in more conservative estimates, which should tend to include rather than exclude more respondents from this set of questions.) These items are part of the "Income" area of interest.

The following descriptions of Assets, Debts & Expenditures data are divided into the following subsections:

• General information about assets questions
• Topcoding
• Respondents living abroad
• Wills
• Philanthropy
• Financial literacy and practices
• Debt and personal finance
• Foreclosure
• Revisions to resolve asset and debt issues
• Details about computed net wealth variables
• Household expenditures
• Educational expenditures

General information about assets questions

From the first survey year, NLSY79 respondents have been asked about their savings, home, and vehicle ownership. Over the course of the survey, these questions provide information on when saving begins, how savings habits are formed, and how persistent savings habits are.

Each of the first four surveys (1979-1982) contain identical sets of questions asking if the respondent or their spouse had any money set aside for savings, owned a vehicle, or owned their own home. In those early years however, the respondent was not asked how much savings were held, the value or number of vehicles, or the value of, and mortgage on, their home. Additionally, respondents were only asked questions on assets if they met one of following five criteria:

• 18 years old or greater
• Had a child
• Enrolled in college
• Married
• Living outside their parents' home

This selection process eliminated many respondents from these questions. Early NLSY79 data show that few individuals answered the questions until they turned 18 years old. For example, in 1979 only five percent of those interviewed under age 18 answered the asset questions. Except for the question on home ownership, asset questions were dropped during 1983 and 1984. Beginning in 1985, when all respondents had turned 18, NLSY79 respondents were administered a much larger wealth section. As Table 1 shows, respondents were given the opportunity to answer approximately 20 questions about a variety of asset and debt holdings. In most years respondents estimated how much their home, cash savings, stock and bond portfolio, estate, business, and automobile were worth. Additionally, respondents estimated how much mortgage debt, property debt, and other debt they had accumulated. Together these variables provide a rough overview of the net wealth of each respondent. As the cohort has aged, the assets module has grown in length and detail.

Topcoding

Because the NLSY79 is a public use data set that is distributed widely throughout the research and public policy communities, the survey takes extensive measures to protect the confidentiality of respondents. One method of ensuring confidentiality is to "top code" unusually high values.

Over time, the NLSY79 has used three topcoding algorithms for assets. From 1979 to 1988, every NLSY79 asset question that elicited a response above a specified cutoff value, such as $150,000 for some asset variables, was recoded to the truncation value plus one dollar, such as $150,001. Unfortunately this algorithm results in a sharp downward bias in the mean value of NLSY79 asset holdings since the entire right hand tail is truncated. To address this problem, beginning in 1989, a new algorithm was implemented, which replaced all values above the cutoff with the average of all outlying values.

Beginning in 1996, the top two percent of respondents with valid values were identified. Values within that top range were averaged and that averaged value replaced all values in the top range.

The extent of topcoding for NLSY79 asset questions varies greatly. For example, in 1993 there were only two individuals whose money assets exceeded the cut-off value of $500,000, while 581 individuals gave a market value for their residence above the cut-off value of $150,000. While topcoding presents problems in analysis of individual observations and alters some statistical properties, this algorithm has not affected the estimates of mean and median holdings. Table 2 shows the number of people shielded by top codes in both 1985 and 1993.

Several sets of asset values are included in the 2022 Retirement Expectations module. These 2022 asset values have been topcoded using an updated set of decision rules. These rules were formulated based on the two percent method described above, with some modifications for the treatment of extreme outliers and very low frequency variables.

Respondents living abroad

A second out-of-range issue with NLSY79 data concerns individuals living outside the United States. Residing outside the United States does not preclude a respondent from being interviewed. For example, in 1992, 125 interviewed respondents lived abroad. Between 1989 and 1992, for people who hold assets denominated in foreign currency, little effort was made to transform these assets into dollar figures. Instead, such values are classified as "invalid skips" in the data. Beginning in 1993, an effort was made to convert these currencies whenever the unit of the response could be determined. While researchers are warned that this occurs, relatively few respondents live outside the United States and only a small number of individuals in this group cannot report their wealth in U.S. dollars. Based on analysis of comments and data in the 2022 survey data, reported asset values have been treated as U.S. dollars unless a foreign currency is specifically identified by the respondent.

Wills

As NLSY79 respondents are all into their 50s and beginning to enter their 60s, it is important to augment information on health, asset accumulation and retirement plans with information on NLSY79 respondents' estate planning. Beginning in 2012 a set of questions on wills was administered and continued to be asked through 2018. These questions were drawn from the 2006 wave of the Health and Retirement Study and also have overlap with questions asked in the final rounds of the NLS Women survey. 

The new questions identify whether respondents have a will, a trust, or both, when it was established, when and why it was last modified, whether it provides for children and for grandchildren and, if so, whether it provides for them equally, and whether it provides for charities or nonprofit organizations. Respondents who report no will or trust are asked whether they intend to establish one.

This section ends by asking whether respondents have long-term care (LTC) insurance. While relatively few respondents are expected to have LTC insurance at this stage in the life-cycle, planning for costly health care expenses is intrinsically linked to bequest planning. 

Financial literacy and practices

In 2012 eight new questions on financial literacy and practices were asked of all respondents. These questions ask respondents about their preparedness for financial emergencies, their ability to monitor financial matters, and their knowledge of core financial concepts. These questions were originally asked in the Health and Retirement Study in 2004 and the Financial Capability Study. This short module complements the questions on wills and estates, and is consistent with ongoing plans to learn more about respondents' financial literacy, practices, and preparedness as they begin planning in earnest for retirement in their 50s and 60s. This series of questions was repeated in 2014, 2016, and 2018 for those who did not have the chance to answer them in 2012. They can be found in the Attitudes & Influence area of interest.

Debt and personal finance

Beginning in 2004, respondents have answered more detailed questions about their debt and personal finance histories. Respondents report total amounts owed on all credit card accounts, in student loans for which they or their spouse or partner are responsible, to other businesses or to other people/institutions/companies over $1000. Respondents are also asked if they have missed bill payments or been at least two months late in the last five years and the number of credit cards on which they owe the maximum amount (if any). Respondents reporting any bankruptcies within a specified reference period are asked how many bankruptcies they have declared. Information is then collected for the most recent bankruptcy, including whether the bankruptcy was related to the failure of a business and the date and type of bankruptcy declaration. Finally, respondents are asked if in the last five years they or their spouse or partner have applied for credit or a loan and been turned down or have chosen not to apply assuming they would be turned down. These variables can be found in the Debt area of Interest in survey years 2004-2016.

Revisions to resolve asset and debt issues

A revised set of asset and debt variables is included in the public data release for survey years 1985-2000. These revised variables address a number of anomalies in the NLSY79 data by eliminating some implausible outliers and generating uniform topcodes for all rounds. The following provides details on the revision process.

The original version of each revised variable is still present in the data. For example, in 1987 each respondent who owned a home or apartment was asked the market value of their residential property ("About how much do you think this property would sell for on today's market?"). The data include both the original version of this variable and a revised version:

• R23627.00   Q13-118 MARKET VALUE OF RESIDENTIAL PROPERTY R/SPOUSE OWN (TRUNC)
• R23627.01   Q13-118_REVISED MARKET VALUE OF RESIDENTIAL PROPERTY R/SPOUSE OWN (TRUNC) (REVISED)

The variable with the reference number ending in (.00) R23627.00 is the original variable in the dataset and is left so that researchers can reproduce previous results. The reference number ending in (.01) R23627.01 is the variable that uses a revised topcoding algorithm. By revising the variable, researchers are now provided with some extra information that was not available before. Revised assets and debt variables can be found by searching Assets area of interest with question names ending in "REVISED" for survey years 1985-2000.

A more detailed explanation is available in NLSY79 Appendix 23: Revised Asset and Debt Variables and Computed TOTAL Net Wealth Variables. 

Details about computed net wealth variables

In calculating total net family wealth (TNFW_TRUNC), an intermediate set of variables is created representing specific categories of assets and debt. These intermediate variables are useful for researchers who want to probe a particular aspect of a respondent’s financial life, such as their debts or ownership of vehicles. Appendix 23 includes additional information about these categorical components of total net family wealth.

Household expenditures

In 2006, respondents answered a series of questions about regular (monthly or weekly) household expenses, including grocery/non-grocery purchases, telephone, internet, electricity, and other utility bills. These variables can be found by searching for the Consumption area of interest in NLS Investigator.

Educational expenditures

Respondents who were parents answered a series of questions in 2014 regarding the costs of their children’s education for high school (for children attending private school grades 9-12) and post-secondary institutions (two-year or four-year colleges). They were first asked the total expense incurred (amount borrowed or paid) by respondent, student, family, and friends. Respondents then reported the percentage of the total they and their spouse/partner, another parent, grandparents, the child him/herself, and/or other relatives/friends had each paid. In addition, respondents answered the following speculative questions about their children and college where applicable:

• Do you believe [name of child] would have attended a more expensive college or attended college for a longer time if you and other family members had been able to contribute more...?
• Do you believe [name of child]'s decision not to attend college was influenced by concerns about the cost of college?
• If [name of child] had attended college, do you believe you and other family members would have contributed [to the expenses]?
• Given that [name of child] did not attend college, did you give him/her money that might otherwise have been used for college-related expenses?

Every round of the NLSY79 has included a section on fertility. The first three rounds of the NLSY79 (1979, 1980, and 1981) have very short fertility sections.

Fertility history

Researchers can create fertility event histories in a number of ways. One method is to extract the variables from each year's survey data which record when each child was born. However, NLSY79 data show that this is not an accurate method for creating an event history. In each survey, respondents are asked to correct information in the fertility roster. (Prior to 1993, this was the Children's Record Form or CRF. Beginning in 1993, this is the BIO/NBIO Child Roster). Each year, numerous changes are made. For example, in the 1994 survey, parents changed some portion of the birth record for 548 children. While this number appears high, the vast majority of changes are to the spelling of children's names.

Because the raw recorded data on dates of birth, sex, and status (adopted, deceased) entered on the Children's Record Form (CRF) are subject to interviewer as well as respondent error, NLSY79 staff created a fertility event history beginning in 1982. This was done to aid users and, at the same time, evaluate the quality of the NLSY79 fertility data. This series, found in the "Fertility and Relationship History/Created" area of interest, lists a number of variables including the birth month, and year of every child born to NLSY79 respondents; numbers and outcomes of pregnancies; ages of respondents at the birth of selected children; dates of death for children who have died; and usual residence of children.

Age at first birth

Beginning in 1982, every NLSY79 data release has included a created variable that tracks the age of respondents when they first give birth. Readers can also find created variables in the "Fertility and Relationship History" area of interest that track how old the respondent was when the second and third births occurred.

Fertility expectations and desires

The fertility section provides researchers with an opportunity to examine whether expectations about the future compare accurately with what actually happens in respondents' lives. In 1979 and 1982, respondents were asked how many children they desired, which can be found in question name FER-1B. 

In 1979, 1982–1986, 1988, 1990, 1992, and 1994–2012, respondents provided information on the number of children they expected to have. This question was discontinued after 2012.

Fertility and relationship history

The 2000 release of the NLSY79 data introduced a new series of constructed variables for each survey year that provide information about the respondent's relationship status. All surveys were examined to match names of spouses or partners for the entire administration of the NLSY79. The first variable provides information about the respondent's total number of spouses or partners since 1979 and can range from 0 to 9. The percentage of respondents who have never reported having a spouse or partner can be found in Table 3.

Second, a unique code is assigned to each new spouse/partner at the interview date. If the same spouse or partner resides with the respondent during the next survey round, the spouse or partner code remains the same. If the respondent has a new spouse or partner, the next available number is given to that person. If in a later survey round the respondent is reunited with a previous spouse or partner, the number of spouse/partners is not increased, and the code for that year reflects that spouse/partner's original number.

The second created variable reveals whether the person living with the respondent is a spouse, coded 1, or a partner, coded 33. In some instances, the exact relationship is indeterminate in a given round; in these cases, a code of 36 is used. If no spouse or partner is present at a given survey point, but the respondent has reported a spouse/partner in the past, their relationship code will be zero. Respondents with no known spouses/partners receive a code of -999. 

There is no guarantee that the same individual(s) were present between survey rounds or that all partners are accounted for, as a spouse or partner may have appeared between survey rounds but not have been present at any survey point. Early examination suggests that this applies to only a modest proportion of cases. In some instances, identification of spouses who only were present between rounds may be possible by using the NLSY79 marriage history, as well as the marriage transition information available at each survey point.

References

Mott, Frank L., Paula Baker, R. Jean Haurin, and William Marsiglio, "Fertility Related Data in the 1982 National Longitudinal Survey of Work Experience of Youth: An Evaluation of Data Quality and Preliminary Analytical Results." Columbus, OH: CHRR, The Ohio State University, 1983.

Mott, Frank L. "Evaluation of Fertility Data and Preliminary Analytical Results from the 1983 (Round 5) Survey of the National Longitudinal Surveys of Work Experience of Youth." Columbus, OH: CHRR, The Ohio State University, 1985.

Mott, Frank L. "Male Data Collection: Inferences from the National Longitudinal Surveys." Columbus, OH: CHRR, The Ohio State University, 1998.