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Household, Geography & Contextual Variables
Age
The NLSY79 Child and Young Adult data files include several distinct child age variables at each survey point. The most appropriate age variable to use may depend on one's research objectives. The age variables found in the two Areas of Interest called CHILD BACKGROUND (for all children) and in YA COMMON KEY VARIABLES (for Young Adults) reflect consistency checks and a small number of edits based on additional information. All the created child age variables in the CHILD BACKGROUND area of interest are computed in months, regardless of whether they refer to children who are currently 0-14 or young adults who are now 15 and older. The codebook, however, displays these "age in months" variables in grouped ranges for ease of viewing. The "age of child at mother's interview date" variables (AGECH) that are assigned to the CHILD BACKGROUND area of interest are created for all children (including young adults), regardless of age. Also, children who are currently young adults are still represented in the variables that indicate child age at assessment date for the survey rounds when they were actually assessed. These child assessment age variables describe the age of the (now) young adult at the time s/he was assessed in prior survey rounds. Generally, most young adults will only have assessment age data for years when they were under the age of 15; however, in the early Child survey years before the start of the Young Adult data collection, some young adults were assessed even though they were older than 14.
The variable that describes the mother's age at the birth of the child (MAGEBIR) is computed in years as is the mother's age at interview date (AGEMOM) which is in the FAMILY BACKGROUND area of interest. The ages for young adult children, available in the Young Adult areas of interest, are also computed in years (e.g., AGE1B assigned to YA FERTILITY AND RELATIONSHIP DATA - CREATED, and AGEDEC, AGEINT in YA COMMON KEY VARIABLES). Users are encouraged to rely on the created age variables rather than any age variables that are direct pick-ups from the questionnaires in the various survey rounds.
Child Age Variables
Created Variables
AGECHyyyy. AGE OF CHILD (IN MONTHS) AT INTERVIEW DATE OF MOTHER
CSAGEyyyy. AGE OF CHILD (IN MONTHS) AT CHILD ASSESSMENT DATE, CHILD SUPPLEMENT
MSAGEyyyy. AGE OF CHILD (IN MONTHS) AT CHILD ASSESSMENT DATE, MOTHER SUPPLEMENT
PPVTMOyyyy. PPVT AGE OF CHILD (IN MONTHS) AT CHILD ASSESSMENT DATE
There are four relevant age variables for younger children. In most but not all instances, the values for these age variables will be the same in any one survey year. Unlike the age variables for the young adults, age variables for children under age 15 are computed in months, so users who prefer a variable in which the unit is in "years" will need to apply formats or perform a simple conversion.
One series of child age variables (AGECH) references the age of the child as of the mother's interview date.Similarly, there is a Child Supplement assessment age (CSAGE) based on the date the interviewer-administered assessments in the Child Supplement were given. Another age variable series (MSAGE) is linked to the date the Mother Supplement was administered. This variable, termed "Child age at mother supplement date," is appropriate to use when one's research utilizes an assessment that was administered as part of the Mother Supplement questionnaire. The child supplement assessment ages and the mother supplement ages are assigned to the CHILD BACKGROUND area of interest.
Finally, there is a child age variable (PPVTMO) that references the date the child was administered the PPVT assessment. In creating the PPVT age in months, a child's age is rounded up to the next month if he or she is more than 15 days through a given attained month as of the survey date. PPVT age is found in the year-specific ASSESSMENT area of interest.
Which Age Variable is Best? Users are advised to exercise caution when applying age variables in conjunction with the child assessment data. Some unedited child date of birth and age variables may appear in the CHILD SUPPLEMENT and MOTHER SUPPLEMENT areas of interest. These items, not available for all children, appear exactly as recorded in the field. Users are generally discouraged from using these items as reported directly from the questionnaires and instead are urged to rely on the child age variables found in the CHILD BACKGROUND or ASSESSMENT areas of interest.
Most of the child assessments are designed to be administered to select age groups of children. For example, Part D of the Motor and Social Development Scale is intended for children 10-12 months of age, while PIAT Math is administered to children whose PPVT age is 5 years or older. Since assessment dates are not always the same for the Child Supplement and the Mother Supplement, users should apply the age variable specific to the supplement that was used to administer the particular assessment. In 2000 (and only 2000) this issue became somewhat more complex in that two mother-report assessments (the HOME and Temperament) were administered in the Child CAPI Supplement for children under age 4. In all years except 2000, it is advisable to use the Mother Supplement age at assessment (MSAGE) for the HOME and Temperament scores. In 2000 the Child Supplement age (CSAGE) was a more accurate indication of assessment age of children under age 4 for these two measures.
Important Information
Beginning with the 2006 survey year, MSAGEyyyy and AGECHyyyy are identical because the Mother Supplement assessments are integrated into the mother's main Youth questionnaire.
Young Adult Age Variables
Created Variables
AGEDECyyyy. AGE OF YOUNG ADULT (IN YEARS) AS OF DECEMBER 31
AGEINTyyyy. AGE OF YOUNG ADULT (IN YEARS) AT DATE OF INTERVIEW
There are two Young Adult age variables most appropriate for use. In contrast with the variables for the younger children, these are computed as age-in-years. One references the Young Adult's age at his or her interview date and is the variable that most people will want to use (Y33319.00 in 2014). The second is the Young Adult's age on the last day of the calendar year for that survey round (see Y33320.00 in 2014). This variable is included because December 31 of a given reference year defines the eligibility of a child for inclusion in the young adult sample. Starting in 1994, a child must be 15 or older as of that date to be included in the young adult sample. This is the reason that the tables in this report that provide child age as of an interview date split 14-year-olds into a Child group and a Young Adult group. The age at end of year variable can also be useful for defining a sample according to an unchanging age cohort as of any interview year. Interview dates are rarely exactly two years apart; therefore, an individual who is age 20 at one interview point, while typically 18 at the preceding interview, might possibly have been 19 or 17.
Age & Demographics
Created Variables
CYRB. DATE OF BIRTH OF CHILD - YEAR
CMOB. DATE OF BIRTH OF CHILD - MONTH
CDYB. DATE OF BIRTH OF CHILD - DAY (GEOCODE)
FSTYRAFT. 1ST SURVEY YEAR OF MOTHER FOLLOWING DATE OF BIRTH OF CHILD
A number of child background variables are provided in the child data files that designate each child's date of birth, birth order, sex, and mother's race. This series of variables is updated in each release to reflect information for all children as of the current survey point, including children who have become young adults. These key variables, assigned to the CHILD BACKGROUND area of interest, are updated to incorporate children born since the last interview. The demographic information is also reviewed in light of mother updates from the main Youth file. Included in this series is an indication of the child's usual residence at the time of the mother's survey. From 1979-1981 and in 1983 and 1985 the child's residence status is based on reports from the mother's household roster. In all other years, child residence information is derived from the child-specific questions on "with whom the child usually lives" in the Fertility section of the main Youth questionnaire. The set of variables in CHILD BACKGROUND also includes a variable, FSTYRAFT (C00052.00), that can be used for connecting child events with information linked to the mother's survey date.
Important Information
The child's "day" of birth (CDOB) is available only on the Geocode version of the data.
Data Updates and Child Age
Information on a child's date of birth from the Children's Record Form (CRF), an instrument used with the main NLSY79 until recent rounds, was the source of birth date information for the Child Supplements. Beginning in 1988, a Child Face Sheet was introduced as an aid to interviewers in the calculation of child ages. This instrument contained a preprinted child birth date or a place for the interviewer to record the child's date of birth from Part A of the CRF and provided a place for calculating child age and PPVT age in reference to the Child Supplement interview date. This paper Face Sheet was replaced in 1994 by a CAPI feature that computed child age so that interviewers could anticipate which assessments would be administered.
A child's birth date may occasionally be altered on the basis of new information received from the mother in conjunction with the internal evaluation procedures carried out at CHRR. Thus, in a small number of cases, date of birth and child age information may not be completely consistent across all survey rounds. Appendix 5: NLSY79 Supplemental Fertility File Documentation, in the NLSY79 Codebook Supplement, discusses cases in which child birth dates were edited.
Over the interview years occasional revisions have been made to a child's date of birth if it was found to be in error. However, the questions and assessments administered to a child were contingent on the child's age as specified at the time. For a variety of reasons, no attempt has been made to alter the historical age record when a date of birth was revised. Thus, when using age-sensitive information from prior interview points, two options are often possible. One option is to recreate an age variable based on the most recent date of birth of child in conjunction with the interview date in that year. (Note that if this changes the child's age, it may not longer mesh appropriately with the age-specific assessment information collected for that child). The second option is to use the set of age variables from that year, a variable that will be consistent with all the other information gathered from the child in that year. In most instances, this latter option is probably the preferred solution. Finally, in almost no instance would it be appropriate to simply decrement a child's age by the number of years between the most recent interview and the interview round of interest. This can often lead to incorrect estimates for the reason noted above.
Comparison to Other NLS Surveys: Age data are available for all NLS cohorts. These variables include both the age of the respondents as of a fixed date during the initial survey year and as of the interview date in various years. Date of birth is also available for all cohorts. 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.
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
- Asterisk Tables
- Education
- Employment
- Employment: An Introduction
- Work Experience
- Jobs & Employers
- Class of Worker
- Discrimination
- Fringe Benefits
- Industries
- Job Characteristics Index
- Job Satisfaction
- Job Search
- Labor Force Status
- Military
- Occupations
- Time & Tenure with Employers
- Wages
- Work History Data
- Employer History Roster
- Business Ownership
- Retirement
- Household, Geography & Contextual Variables
- Family Background
- Marital History, Childcare & Fertility
- Income
- Health
- Attitudes
- Crime & Substance Use
- 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
- Questionnaires
- Tutorials
- Errata
- Technical Sampling Report
- School & Transcript Surveys Documentation
- Codebook Supplement
- Get Data
- Topical Guide to the Data
- NLSY79 Child/YA
- Topical Guide to the Data
- Intro to the Sample
- 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