1. Work History Data 1.Overview the key employment-related work history variables in the NLSY79 and NLSY97. 2.Examine selected work history variables for one NLSY79 respondent to see how his employment activities are summarized. 3.Consider alternative ways to measure work experience and job mobility.

2. Part 1 Overview of Employment-Related Work History Variables in the NLSY79 and NLSY97

3. A. NLSY79 & NLSY97 Weekly Arrays DefinitionNLSY79 QNameNLSY97 QName Labor force status: STATUS_WK_NUMxxxxEMP_STATUS.year.wk Hours worked per week: HOURS_WORKED_ WK_NUMxxxx EMP_HOURS.year.wk Dual job status:JOB_WK_NUMxxxx_ DUALJOB_NUMx EMP_DUAL_x_year.wk Each array contains one variable per week Week 1 begins on January 1, 1978 in the NLSY79

4. B. Other Employment Variables (NLSY79 & NLSY97) DefinitionNLSY79 QNameNLSY97 QName Start date (job) START_WK#_year _JOB#n EMP_START_WEEK_syr.job# EMP_START_YEAR_syr.job# Stop date (job) STOP_WK#_year _JOB#n EMP_END_WEEK_syr.job# EMP_END_YEAR_syr.job# Start date (within-job gap) PER#_START_year _JOB# EMP_GAP_START_WEEK _syr.job.gap EMP_GAP_START_YEAR _syr.job.gap Stop date (within-job gap) PER#_STOP_year _JOB# EMP_GAP_END_WEEK _syr.job.gap EMP_GAP_END_YEAR _syr.job.gap

5. B. Other Employment Variables (NLSY79) Definition Survey Years NLSY79 QName Start date (period not working between jobs) AllBSTART_year_PERIOD# Stop date (period not working between jobs) AllBSTOP_year_PERIOD# Start date (military service) AllMIL_START#_year Stop date (military service) AllMIL_STOP#_year Week of the current interview: AllCURRINT__WK#_year Week of the last interview: AllLASTINT__WK#_year Job number assigned to employer from last interview: AllPREV_EMP#_year_JOB#n

6. B. Other Employment Variables (NLSY97) Definition Survey Years NLSY97 QName Number of weeks prior to DLI in which the EMP_STATUS.year.wk variable would have changed had this job been included in the last interview. 2000+EMP_BK_STATUS_syr Number of weeks prior to DLI that job began. 2000+EMP_BK_WKS_syr Number of hours prior to DLI that would have been included in the EMP_HOURS.year.wk array had this job been included in the last interview. 2000+EMP_BK_HOURS_syr

7. Part 2 Examine Selected Work History Variables for one NLSY79 Respondent

8. Our Respondent We will follow a single NLSY79 respondent (CASEID=15) from 1990 to 1993. The examples show how selected work history variables convey this respondent’s employment activities.

9. A. Job Start Dates and Stop Dates 1990 interview CURRINT_WK#_1990 = 658  1990 interview is held the week of 8/5/90 (week 658). START_WK#_1990_JOB#n =. (for n=1,2,3,4,5) STOP_WK#_1990_JOB#n =. (for n=1,2,3,4,5)  The respondent reports no current job, and no jobs held since the last interview.

10. 1991 interview CURRINT_WK#_1991 = 705  1991 interview is held the week of 6/30/91 (week 705). START_WK#_1991_JOB#01 = 674 STOP_WK#_1991_JOB#01 = 705  The respondent reports a job that began in week 674.  The job does not “stop” in week 705. The interview week is used as a pseudo-stop week to indicate that the job is ongoing. [A variable in the Job Information file confirms that the respondent is currently working for this employer.]  In this example, we will refer to this job as Job A. START_WK#_1991_JOB#n =. (n=2,3,4,5) STOP_WK#_1991_JOB#n =. (n=2,3,4,5)  The respondent reports no other jobs held since the last interview.

11. Based on this reported information we know that, as of week 705, the respondent’s work history looks like this: 658674705 Job A begins 1990 interview 1991 interview (Job A in progress)

12. 1992 Interview CURRINT_WK#_1992 = 755 LASTINT_WK#_1992 = 706  1992 interview is held the week of 6/14/92 (week 755).  LASTINT_WK is last year’s interview week +1. PREV_EMP#_1992_JOB#01 =1 START_WK#_1992_JOB#01 = 706 STOP_WK#_1992_JOB#01 = 755  The “previous employer” variable indicates that this year’s job #1 is identical to last year’s job #1.  We continue to refer to this job as Job A.

13. 1992 Interview, continued PREV_EMP#_1992_JOB#01 =1 START_WK#_1992_JOB#01 = 706 STOP_WK#_1992_JOB#01 = 755  Job A does not “start” in week 706. The last interview week is used as a pseudo-start week to indicate that this job is a continuation of a job reported last year.  Job A does not “stop” in week 755. The interview week is used as a pseudo-stop week to indicate that the job is ongoing. START_WK#_1992_JOB#n =. (n=2,3,4,5) STOP_WK#_1992_JOB#n =. (n=2,3,4,5)  The respondent reports no other jobs held since the last interview.

14. As of week 755, the respondent’s work history looks like this: Job A begins 1990 interview1991 interview 658 1992 interview (Job A in progress) 755 674705

15. 1993 Interview CURRINT_WK#_1993 = 810 LASTINT_WK#_1993 = 756  1993 interview is held the week of 7/4/93 (week 810).  LASTINT_WK is last year’s interview week +1. PREV_EMP#_1993_JOB#02 =1 START_WK#_1993_JOB#02 = 756 STOP_WK#_1993_JOB#02 = 767  The “previous employer” variable indicates that this year’s job #2 is identical to last year’s job #1.  Job A does not “start” in week 756. The last interview week is used as a pseudo-start week to indicate that this job is a continuation of a job reported last year.  Job A ended the week of 9/6/92 (week 767); this is the job’s true stop date.

16. 1993 Interview, continued START_WK#_1993_JOB#01 = 771 STOP_WK#_1993_JOB#01 = 810  The respondent reports a new job that began the week of 10/4/9 (week 771).  In this example, we refer to this new job as Job B.  Job B does not “stop” in week 810. The interview week is used as a pseudo-stop date to indicate that the job is ongoing. START_WK#_1993_JOB#n =. (n=3,4,5) STOP_WK#_1993_JOB#n =. (n=3,4,5)  The respondent reports no other jobs held since the last interview.

17. As of week 810, his work history looks like this: Job A begins 1990 interview 1991 interview 658 674 705 1992 interview 755767 Job A ends Job B begins 771810 1993 interview (Job B in progress)

18. A. Job Start Dates and Stop Dates Users may wish to create their own variables identifying the “true” start week and stop week of each job held For example, we might create the variables:  STARTx = start week of job x, where x indexes the 1st through last job encountered in chronological order  STOPx = stop week of job x  CENx = 1 if job x is right-censored (in progress when the respondent is last interviewed) and 0 otherwise

19. If our respondent (CASEID=15) were only seen from 1990 to 1993, these variables would take on the following values: START1=674START2=771 STOP1=767STOP2=810 CEN1=0CEN2=1 Note: If we begin following this respondent in 1979, Job A is not his first job. Similarly, if we follow him beyond 1993, Job B is followed by several additional jobs. For additional information, see:  NLSY79 APPENDIX 9: “LINKING EMPLOYERS THROUGH SURVEY YEARS”

20. The respondent’s weekly labor force status is described by the array of variables named STATUS_WK_NUMxxx These variables can take on the following values: 0: no information reported for week 2: not working (unemployed vs. OLF not determined) 3: associated with employer (gaps missing; time unaccounted for) 4: unemployed 5: out of labor force (OLF) 7: active military service xxnn: employed (xx is round; nn is job number) B. Weekly Labor Force Status

21. 1990 interview CURRINT_WK#_1990 =658 STATUS_WK_NUM647 – STATUS_WK_NUM654 = 4 STATUS_WK_NUM655 – STATUS_WK_NUM658 = 5  The respondent is interviewed in week 658.  He is OLF at the interview date.  This 4-week OLF spell is preceded by an 8-week unemployment spell that began in week 647.  As we will learn “next year,” this period of unemployment/OLF will continue for several more weeks.

22. 1991 interview CURRINT_WK#_1991 = 705 STATUS_WK_NUM659 – STATUS_WK_NUM673 = 4 STATUS_WK_NUM674 – STATUS_WK_NUM705 = 1301  The respondent is interviewed in week 705.  “Last year’s” period of unemployment/OLF continued through week 673.  Recall that he is now holding a job (Job A) that began in week 674.  The status array shows that from week 674 to the current interview week, he is employed on Job A, which is job #1 reported in 1991 (r13).

23. 1992 interview CURRINT_WK#_1992 = 755 STATUS_WK_NUM706 – STATUS_WK_NUM755 = 1401  The respondent is interviewed in week 755.  Recall that he has worked continuously on Job A since the last interview date.  The status array shows that from the last interview week to the current interview week he is employed on Job A, which is job #1 reported in 1992 (r14).

24. 1993 interview CURRINT_WK#_1993 =810 STATUS_WK_NUM756 – STATUS_WK_NUM 767 = 1502 STATUS_WK_768 – STATUS_WK_NUM770 = 4 STATUS_WK_771 – STATUS_WK_NUM810 = 1501  Recall that Job A ended in week 767 & Job B began in week 771.  The status array shows that from the last interview week to week 767 he is employed on Job A, which is job #2 reported in 1993 (r15).  The status array shows that from week 771 to the current interview week he is employed on Job B, which is job #1 reported in 1993 (r15).  The status array shows that he was unemployed for the 3 weeks between Job A and Job B.

25. With the addition of the information in the status array, we know that this portion of the work history looks like this: 658674705755767771 810 647 Job A 1990 interview 1991 interview 1992 interview Job B 1993 interview UnemploymentUnemployment or OLF

26. C. Weekly Hours Worked The respondent’s weekly work effort is described by the array of variables: HRS_WORKED_WK_NUMxxxx These variables give the usual weekly hours worked on all jobs during the particular week.

27. 1990 interview CURRINT_WK#_1990 =658 HRS_WORKED_WK_NUM647 – HRS_WORKED_WK_NUM658 = 0  The respondent is interviewed in week 658.  Recall that the respondent is unemployed or OLF from week 647 to week 658 (and beyond).  The hours array shows that he work zero hours during each week of the unemployment/OLF spells.

28. 1991 interview CURRINT_WK#_1991 = 705 HRS_WORKED_WK_NUM659 – HRS_WORKED_WK_NUM673 = 0 HRS_WORKED_WK_NUM674 – HRS_WORKED_WK_NUM705 = 50  The respondent is interviewed in week 705.  The hours array shows that he worked zero hours for the duration of “last year’s” unemp/OLF spell.  Recall that the respondent began Job A in week 674.  When interviewed in week 705, the respondent reports his “usual weekly hours” on Job A to be 50.  The hours array shows 50 hours for every week since Job A began.

29. 1992 interview CURRINT_WK#_1992 = 755 HRS_WORKED_WK_NUM706 – HRS_WORKED_WK_NUM755 = 55  The respondent is interviewed in week 755.  Recall that the respondent has worked on Job A since the last interview.  When interviewed in week 755, the respondent reports his “usual weekly hours” on Job A to be 55.  The hours array shows 55 hours in every week since the last interview.

30. 1993 interview CURRINT_WK#_1993 = 810 HRS_WORKED_WK_NUM756 – HRS_WORKED_WK_NUM767 = 50 HRS_WORKED_WK_NUM768 – HRS_WORKED_WK_NUM770 = 0 HRS_WORKED_WK_NUM771 – HRS_WORKED_WK_NUM810 = 40  When interviewed in week 810, the respondent reports his “usual weekly hours” on Job A (which ended in week 767) to be 50.  When interviewed in week 810, the respondent reports his “usual weekly hours” on Job B (which began in week 771) to be 40.  The hours array shows that he worked zero hours during each week of the intervening unemployment spell.

31. Part 3: Measuring Work Experience and Job Mobility Examples from the NLSY79 (and YA)

32. A. Cumulative Work Experience In cross-sectional surveys, data on actual work experience are scarce. As a result, we often use “Age-Schooling-6” as a proxy for work experience.  At the interview date, the respondent reports his age and years of schooling (S).  We approximate his school exit date as age S+6 and his experience as the time elapsed since that date. Born Assumed to begin school Assumed to end school Interviewed (report age & S) 6 yrsS yrsAge-S-6 yrs

33. With NLS data, we have many options for measuring work experience.  We need not “start the clock” on work experience at age S+6. We can pick any date as the starting date (t 1 ).  We can also pick any date as the stopping date (t 2 ).  We need not measure experience as “elapsed time.” Instead, we can count the number of weeks actually worked, the (usual) number of hours worked, etc.

34. Defining t 1 and t 2 : Depending on one’s substantive focus, possibilities include:  Let t 1 be the actual date of school exit (e.g., first exit, last exit, or first exit lasting at least N months)  Let t 1 be the date of college entry and t 2 be the date of college exit; this allows us to measure work experience gained while in college.  Let t 1 be a particular age (e.g., the 18th birthday). This allows us to measure all respondents’ work experience from a uniform date regardless of their school enrollment behavior.  Let t 1 be the job start date and t 2 be the job stop date. This allows us to measure experience with a particular employer. Born Begin school Actual school exit date (t 1 ) S 1 yrsS 2 yrs Break from school

35. Defining the unit of measurement: Possibilities include:  Cumulative number of months (or 4-week intervals) in which any experience was gained.  Cumulative number of weeks in which any experience was gained.  Cumulative number of weeks in which the individual worked full-time (e.g., usual hours  35).  Cumulative number of (usual) hours worked.

36. Example 1 Define EXPER1 = cumulative weeks between t 1 and t 2 in which any experience was gained. LFS1-LFS1409 are variables containing elements of the array STATUS_WK_NUMxxx for weeks 1 (1/1/78) through 1409 (12/26/04). T1 and T2 are the start and stop weeks between which we wish to measure work experience; array status (1409) LFS1-LFS1409; EXPER1=0; do k=T1 to T2; if status(k)>7 then EXPER1=EXPER1+1; end; EXPER1=EXPER1/52; Note: this strategy counts military service and “unknown” weeks as 0.

37. Example 2 Define EXPER2= cumulative hours worked between t 1 and t 2 HRS1-HRS1409 are variables containing elements of the array HOURS_WORKED_WK_NUMxxxx for weeks 1 (1/1/78) to 1409 (12/26/04) T1 and T2 are the start and stop weeks array hrs (1409) HRS1-HRS1409; EXPER2=0; do k=T1 to T2; if hrs(k)>0 then EXPER2=EXPER2+HRS(k); end; EXPER2=EXPER2/2000; Note: this strategy counts “unknown” weeks as HRS=0.

38. Example 3 Define JOB= 1 if a job is held at t 1 ; JOB=0 otherwise. (In contrast to the preceding examples, this is not a measure of cumulative experience.) START1-STARTX and STOP1-STOPX are user-created variables representing the start and stop dates of every job held. To make the example concrete, assume X=40 (i.e., 40 is the maximum number of jobs reported by any R). T1 is the date of interest (e.g., a given age). array STARTS (40) START1-START40; array STOPS (40) STOP1-STOP40; JOB=0; If T1>0 then do k=1 to 40; if STARTS<=T1<=STOPS then JOB=1; end;

39. Example 3, continued Let T1 be the week of the 20 th birthday Compare JOB for NLSY79 mothers & their YA daughters Mother holds job at age 20 No Yes All No 1074 (71%) 437 (29%) 1511 (69%) Yes 419 (62%) 257 (38%) 676 (31%) All1493 (68%) 694 (32%) 2187 Daughter holds job at age 20

40. B. Cumulative Number of Jobs Held We may wish to measure: Cumulative number of jobs begun between any two points t 1 and t 2 (e.g., from school exit to the interview date). Cumulative number of jobs ended between any two points t 1 and t 2 Cumulative number of job-to-job transitions between any two points t 1 and t 2

41. Example 4 Define JOBBEG = # of jobs begun between t 1 and t 2 Define JOBEND = # of jobs ended between t 1 and t 2 START1-STARTx and STOP1-STOPx are user-created variables representing the start and stop dates of every job held; CEN1-CENx are user-created variables equal to 1 if the job is right-censored, and 0 otherwise. To make the example concrete, assume x=40; i.e., 40 is the maximum number of jobs reported by any respondent.  T1 and T2 are the start and stop weeks between which we will obtain our job count.

42. Example 4, continued array STARTS (40) START1-START40; array STOPS (40) STOP1-STOP40; array CENS (40) CEN1-CEN40; JOBBEG=0; JOBEND=0; do k=1 to 40; if T1<=STARTS(k)<=T2 then JOBBEG=JOBBEG+1; if (T1<=STOPS(k)<=T2 and CENS=0) then JOBEND=JOBEND+1; end;