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Dating, Marriage & Cohabitation; Sexual Activity, Pregnancy & Fertility; Children
Fertility
Created Variables
CC#DOB: Dates of birth of each child
C#SEX: Gender of each child
C#ID: Identification number of each child
C#RES_DLI: Usual residence of each child at most recent interview
C#DOD: Date of death of each child
NUMKID: Number of children ever born to the respondent as of the latest interview
AGE#B: Age at first, second and third birth
MO#B#B: Months between first/second and second/third births
AGE#M: Age began first marriage
MOBG#M/YRBG#M: Month/Year began first/second/third marriage
MOEN#M/YREN#M: Month/Year ended first/second marriage
MO1M1B: Absolute value of months between first marriage and first birth
FL1M1B: A flag indicating whether first marriage occurred before first birth
MOBG1P/YRBG1P: Month/year that first pregnancy began
OUT1P: Outcome of the first pregnancy
AGE1P: Age of respondent at start of the first pregnancy
PREGS, MISCAR, ABORTS: Number of pregnancies, miscarriages/stillbirths and abortions respectively
Important Information About Using Fertility Data
Researchers constructing pregnancy histories should understand a subtle change that began with the 1992 survey. Prior to 1992, the questionnaire asked female respondents to report about pregnancy episodes since the last fertility questions were asked (usually two years earlier). Beginning in 1992, the questionnaire asked respondents detailed questions about pregnancies which ended in a live birth only. While the total number of pregnancies can be determined, distinctions between miscarriages and stillbirths are not made. In addition, while dates of all abortions are collected through the confidential card, only the end date is collected in the fertility section of the first pregnancy that did not result in a live birth. The specific outcome of this pregnancy was not asked and thus could be a stillbirth, miscarriage, or abortion. The "Fertility and Relationship History/Created" area of interest has been part of the NLSY79 data set for many years and consists of edited and constructed variables that incorporate the results of a significant cleaning and editing process begun in the early 1980s. This effort began as part of an evaluation of the retrospective fertility data collection in 1982/1983 in comparison to base year and updated collections that took place in 1979, 1980, and 1981. Additional evaluations have been conducted periodically since then. For further information on the quality of NLSY79 fertility data, users should see Mott et al. (1983) and Mott (1985, 1998). A complete description of the contents of the "Fertility and Relationship History/Created" area of interest is provided in Appendix 5 and also describes how the data were checked, lists research reports that investigate the quality of the data, and explains special coding and edit flags.
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.
Table 1. Year-by-Year Variations in Fertility Data Collection
Variable | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94-2014 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||
Birthdates of any children born (early years since last interview; updates on children at last interview; additional children born since last interview) | * | * | * | * | * | * | * | * | * | * | * | * | * | * | * | * | |
Sex, usual residence, death date (if applicable) for children (updates on children from last interview; children born since last interview) | * | * | * | * | * | * | * | * | * | * | * | * | * | ||||
Contraception/wantedness (females only) | * | * | * | * | * | * | * | * | * | ||||||||
Pregnancy history (females only) | * | * | * | * | |||||||||||||
Pre/post/neonatal care (females only) | * | * | * | * | * | * | * | * | |||||||||
Abortions | * | * | * | * | * | * | * | ||||||||||
Sex education | * | ||||||||||||||||
Left school due to pregnancy (females only) | * | ||||||||||||||||
Visitation information | * | * | * | * | * | * | * | ||||||||||
Total number children desired | * | * | * | * | * | * | * | * | * | * | |||||||
Total number children expected | * | ||||||||||||||||
NON-BIOLOGICAL CHILDREN | |||||||||||||||||
Birthdates, gender | * | * | * | * | * | * | |||||||||||
Adopted or step child | * | * | * |
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.
In 1979, 1982, 1983, 1984, 1985, 1986, 1988, 1990, 1992, and 1994-2012, respondents also reported on the number of children they actually expected to have. After 2012, the question was no longer asked.
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 2.
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.
Table 2. Percentage of Respondents Who Have Never Reported Having a Spouse or Partner
Year | Percentage | Year | Percentage |
1979 | 88.1 | 1992 | 20.0 |
1980 | 82.0 | 1993 | 18.5 |
1981 | 74.7 | 1994 | 17.1 |
1982 | 66.8 | 1996 | 15.3 |
1983 | 58.8 | 1998 | 13.8 |
1984 | 52.1 | 2000 | 12.6 |
1985 | 47.8 | 2002 | 11.9 |
1986 | 41.1 | 2004 | 11.0 |
1987 | 35.3 | 2005 | 10.9 |
1988 | 29.8 | 2008 | 10.4 |
1989 | 25.8 | 2010 | 10.2 |
1990 | 22.9 | 2012 | 9.94 |
1991 | 22.0 | 2014 | 9.84 |
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.
Survey Instruments and Documentation: Information is found in the "Fertility" section of each questionnaire. For additional details on the edited and cleaned fertility data found in area of interest "Fertility and Relationship History/Created," see Appendix 5 in the NLSY79 Codebook Supplement.
Comparison to Other NLS Cohorts: Maternal prenatal care information and health-related characteristics are provided on the NLSY79 Child and Young Adult file and are linked to individual children.
Information on fertility and on the status of children has been regularly collected from the NLSY97 and the Original Cohorts. Data include number of children, dates of birth, sex, and life status. For more precise details about the content of each survey, consult the appropriate cohort's User's Guide using the tabs above for more information.
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.
Survey Instruments and Documentation | See the Sexual Activity & Contraception and Child Care sections of this guide. For information on nonbiological children, see the Household Composition or Gender sections of this guide and areas of interest "Child Record Form/Nonbiological" and "Birth Record xxxx." |
Areas of Interest | Raw unedited data on fertility, pregnancy, sexual activity, and contraception can be found in areas of interest "Children," "Child Record Form/Nonbiological," "Birth Record," and "Birth Record xxxx." Area of interest "Fertility and Relationship History/Created" contains edited and created variables on fertility, pregnancy, and marriage. |
Cohorts
- NLSY97
- Topical Guide to the Data
- Asterisk Tables
- I. Employment, Unemployment, and Job Search (age restrictions as of interview date)
- II. Schooling (age restrictions as of 12/31/96)
- III. Training (age restrictions as of interview date)
- IV. Income, Assets, and Program Participation
- V. Family Formation (age restrictions as of end of previous calendar year--12/31/96 in rd 1, 12/31/97 in rd 2, and so on)
- VI. Family Background (age restrictions as of 12/31/1996)
- VII. Expectations
- VIII. Attitudes, Behaviors, and Time Use
- IX. Health (age restrictions as of 12/31/96)
- X. Political Participation
- XI. Environmental Variables (in main data set)
- Education
- Employment
- Household, Geography & Contextual Variables
- Family Background
- Marital History, Childcare & Fertility
- Income
- Health
- Attitudes
- Crime & Substance Use
- Asterisk Tables
- Intro to the Sample
- Using & Understanding the Data
- Other Documentation
- Codebook Supplement
- Introduction to the NLSY97 Created Variable Appendices
- Appendix 1: Education Variable Creation
- Enrollment Status and Highest Grade/Degree - Appendix 1
- Date Received Diploma or Degree - Appendix 1
- Number of Grades Repeated or Skipped - Appendix 1
- Number of Schools Attended - Appendix 1
- Credits Earned toward Bachelor's/Associate's Degree - Appendix 1
- Date Left High School and Highest High School Grade - Appendix 1
- Private or Parochial School - Appendix 1
- SAT/ACT Scores - Appendix 1
- Training: Receipt of Certificate or Vocational License - Appendix 1
- Appendix 2: Employment Variable Creation
- Appendix 3: Family Background and Formation
- Household Size as of Survey Date - Appendix 3
- Marital Status and Marital/Cohabitation History - Appendix 3
- Fertility and Child Status - Appendix 3
- Number of Residences since Age 12 - Appendix 3
- Current Citizenship Status - Appendix 3
- Mother's Age at First Birth/Respondent's Birth
- Relationship to Household Parent Figures (Round 1 Parent Interview) - Appendix 3
- Relationship to Household Parent Figures (Rounds 7-9 Childhood Retrospective) - Appendix 3
- Relationship to Household Parent Figures (Interview Date) - Appendix 3
- Appendix 4: Geographic Variable Creation
- Appendix 5: Income and Assets Variable Creation
- Appendix 6: Event History Creation and Documentation
- Appendix 7: Continuous Month Scheme and Crosswalk
- Appendix 8: Instrument Rosters
- Appendix 9: Family Process and Adolescent Outcome Measures
- Appendix 10: CAT-ASVAB Scores
- Appendix 11: Collection of the Transcript Data (High School)
- Appendix 12: Post-Secondary Transcript Study
- Attachment 1: Census Industrial & Occupational Classification Codes
- Geocode Codebook Supplement
- Introduction to NLSY97 Geocode Data
- Attachment 100: Census Bureau State and County Codes
- Attachment 101: Metropolitan Statistical Area (MSA)/Core-Based Statistical Area (CBSA) Codes
- Attachment 102: IPEDS Data and College Identification Codes
- Attachment 103: Migration Distance Variables for Respondent Locations
- Attachment 104: Codebook Pages for Geocode and Zipcode Variables
- Questionnaires
- Errata
- Errata for NLSY97 Round 17 Release
- Errata for NLSY97 Round 16 Release
- Addendum: Additional NLSY97 Speech & Post-Secondary Variables Available
- Addendum: NLSY97 Post-Secondary Data and Transcript Data Files Now Available
- Errata for NLSY97 Round 15 Release
- Errata for NLSY97 Round 14 Release
- Errata for NLSY97 Round 13 Release
- Errata for NLSY97 Round 12 Release
- Errata for NLSY97 Round 11 Release
- Errata for NLSY97 Round 10 Release
- Errata for NLSY97 Round 9 Release
- Errata for NLSY97 Round 8 Release
- Errata for NLSY97 Round 7 Release
- Errata for NLSY97 Round 6 Release
- Errata for NLSY97 Round 5 Release
- Errata for NLSY97 Round 4 Release
- Errata for NLSY97 Round 3 Release
- Tutorials
- Technical Sampling Report
- Codebook Supplement
- Get Data
- Topical Guide to the Data
- NLSY79
- Topical Guide to the Data
- Intro to the Sample
- Using & Understanding the Data
- Other Documentation
- Codebook Supplement
- NLSY79 Attachment 3: Industrial and Occupational Classification Codes
- NLSY79 Attachment 4: Fields of Study in College
- NLSY79 Attachment 5: Index of Labor Unions and Employee Associations
- NLSY79 Attachment 6: Other Kinds of Training Codes
- NLSY79 Attachment 7: Other Certificate Codes
- NLSY79 Attachment 8: Health Codes
- NLSY79 Attachment 100: Geographic Regions
- NLSY79 Attachment 101: Country Codes
- NLSY79 Attachment 102: Federal Information Processing Standards (FIPS)
- NLSY79 Attachment 103: Religion Codes
- NLSY79 Attachment 106: Profiles of American Youth (ASVAB Data/AFQT Scores)
- NLSY79 Appendix 1: Employment Status Recode Variables (1979-1998 and 2006)
- NLSY79 Appendix 2: Total Net Family Income Variable Creation (1979-2014)
- NLSY79 Appendix 3: Job Satisfaction Measures
- NLSY79 Appendix 4: Job Characteristics Index 1979-1982
- NLSY79 Appendix 5: Supplemental Fertility and Relationship Variables
- NLSY79 Appendix 6: Urban-Rural and SMSA-Central City Variables
- NLSY79 Appendix 7: Unemployment Rate
- NLSY79 Appendix 8: Highest Grade Completed & Enrollment Status Variable Creation
- NLSY79 Appendix 9: Linking Employers Through Survey Years
- NLSY79 Appendix 11: Round 12 (1990) Survey Administration Methods
- NLSY79 Appendix 12: Most Important Job Learning Activities (1993-94)
- NLSY79 Appendix 13: Intro to CAPI Questionnaires and Codebooks
- NLSY79 Appendix 14: Instrument Rosters
- NLSY79 Appendix 15: Recipiency Event Histories
- NLSY79 Appendix 16: 1994 Recall Experiment
- NLSY79 Appendix 17: Interviewer Characteristics Data
- NLSY79 Appendix 18: Work History Data
- NLSY79 Appendix 19: SF-12 Health Scale Scoring
- NLSY79 Appendix 20: Round 20 (2002) Early Bird and Income Recall Experiments
- NLSY79 Appendix 21: Attitudinal Scales
- NLSY79 Appendix 22: Migration Distance Variables for Respondent Locations
- NLSY79 Appendix 23: Revised Asset and Debt Variables and Computed Net Worth Variables
- NLSY79 Appendix 24: Reanalysis of the 1980 AFQT Data from the NLSY79
- NLSY79 Appendix 25: Center for Epidemiologic Studies Depression (CES-D) Scale
- NLSY79 Appendix 26: Non-Response to Financial Questions and Entry Points
- NLSY79 Appendix 27: IRT Item Parameter Estimates, Scores and Standard Errors
- NLSY79 Appendix 28: NLSY79 Employer History Roster
- Geocode Codebook Supplement
- Appendix 7: Unemployment Rates
- Appendix 10: Geocode Documentation
- Attachment 100: Geographic Regions
- Attachment 101: Country Codes
- Attachment 102: State FIPS Codes
- Attachment 104, Part A: 1981 Standard Metropolitan Statistical Areas (SMSAs)
- Attachment 104, Part B: 1983 Metropolitan Statistical Areas (MSAs)
- Attachment 104, Part C: 1983 Consolidated MSAs and Associated Primary MSAs (CMSAs and PMSAs)
- Attachment 104, Part D: 1983 PMSAs and Associated CMSAs
- Attachment 104, Part E: 1988 MSAs, CMSAs, and Associated PMSAs
- Attachment 104, Part F: 2004 MSAs, CMSAs, and Associated PMSAs
- Attachment 104, Part G: 2006 Core-Based Statistical Areas (CBSAs)
- Attachment 105: Addendum to FICE Codes
- Attachment 106: Codebook Pages for Geocode and Zipcode Variables
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- NLSY79 Child/YA
- Topical Guide to the Data
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- Using & Understanding the Data
- Other Documentation
- Codebook Supplement
- Appendix A: HOME-SF Scales (NLSY79 Child)
- Appendix B: Composition of the Temperament Scales (NLSY79 Child)
- Appendix C: Motor & Social Development (NLSY79 Child)
- Appendix D: Behavior Problems Index (NLSY79 Child)
- Appendix D, Part 1: Composition of the BPI subscales
- Appendix D, Part 2a: BPI Anxious/Depressed Subscale
- Appendix D, Part 2b: BPI Antisocial Subscale
- Appendix D, Part 2c: BPI Dependent Subscale
- Appendix D, Part 2d: BPI Headstrong Subscale
- Appendix D, Part 2e: BPI Hyperactive Subscale
- Appendix D, Part 2f: BPI Peer Conflicts/Withdrawn Subscale
- Appendix D, Part 2g: BPI Full Scale
- Appendix D, Part 3a: BPI Internalizing Subscale
- Appendix D, Part 3b: BPI Externalizing Subscale
- Appendix D, Part 3c: BPI Total Scores
- Appendix E: Sample SPSSx Program for Merging NLSY79 Child/YA & Mother Files
- Appendix F: Sample SAS Program for Merging NLSY79 Child/YA & Mother Files
- Appendix G: NLSY79 Child Assessment Scores, Reference Numbers (2010-2014)
- Appendix H: Identification Codes in the Child and Young Adult Database
- Attachment 100: Codebook Pages for Young Adult Geocode Data
- Questionnaires
- Errata
- Errata for 2014 Child/Young Adult Release
- Data Addition: New Work and School Status Variables Created
- Errata for 2012 Child/Young Adult Release
- Errata for 2010 Child/Young Adult Release
- Errata for 2008 Child/Young Adult Release
- Errata for 2006 Child/Young Adult Release
- Errata for 2004 Child/Young Adult Release
- Errata for 2002 Child/Young Adult Release
- Errata for 2000 Child/Young Adult Release
- Errata for NLSY79 Child Interview Dates 1986-1992
- Research/Technical Reports
- Codebook Supplement
- Get Data
- NLS Mature and Young Women
- NLS Older and Young Men