Created Variables

AGEATINTERVIEW: These variables provide the respondent's age at each interview date.


Important Information About Using Age Data

The eligibility for inclusion in this cohort was based on the 1979 age reports, as are weights. Birth date questions were asked again in the 1981 survey because: 

  • a number of discrepancies between birth dates found on the military file and the NLSY79 files were discovered
  • a number of inconsistencies between age as recorded on the "Household Enumeration" and the main questionnaire were apparent

The 1981 birth dates should be used to determine age with the 1979 dates used only as a backup. Differences between 1979 and 1981 birth dates remained for approximately 200-250 respondents after the 1981 fielding; editing on a case-by-case basis was performed by CHRR staff on only the 1981 variable. Inconsistencies in age or birth date information may appear for a number of reasons:  age and birth date information has been collected at multiple survey points, giving rise to respondent-reported inconsistencies; respondents' ages for sample selection were based on date of birth information reported at the time of the 1978 household screening by individuals who may not have been the respondent; and responses to interviewer check items, that is, the age reported to the interviewer that determines when age-specific questions should be asked, may not be the same age as that calculated from previously reported age or birth date information.  For example, a respondent whose age was 16 as calculated from the birth date reported in 1981 may have answered questions which were specific to a 17 year old.

Date of birth information was collected from each NLSY79 respondent during the 1979 and 1981 interviews:

  • The variable 'Age of R,' gathered during the 1979-83 surveys, is the self-reported age of the respondent as of the interview date. 
  • The NLSY79 main data files also contain a yearly created variable, 'Age of R at Interview Date.' These created variables are constructed using the 1981 date of birth information coupled with the 1979 birth date for the 491 respondents not interviewed in 1981. 

Table 1 depicts age distribution of the NLSY79 for the 1979 survey year. Table 2 depicts age distribution of the NLSY79 for the 2014 survey year.

Table 1. Age of NLSY79 Respondents as of date of interview for the 1979 survey year

Male Female Total
14 504 444 948
15 807 759 1566
16 781 783 1564
17 754 751 1505
18 827 807 1634
19 816 861 1677
20 835 832 1667
21 826 856 1682
22 253 190 443
Total 6403 6283 12686
Note: The table uses the created variable 'Age of R at Interview Date.'

Table 2. Age of NLSY79 Respondents as of date of interview for the most recent survey year

Male Female Total
Not Interviewed 2998 2617 5615
49 0 1 1
50 330 339 669
51 501 493 994
52 473 534 1007
53 465 513 978
54 485 501 986
55 405 432 837
56 365 397 762
57 334 408 742
58 47 48 95
Total 6403
Note: The table uses the created variable 'Age of R at Interview Date.'

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.