NLSY79 Appendix 9: Linking Employers Through Survey Years

National Longitudinal Survey of Youth - 1979 Cohort

NLSY79 Appendix 9: Linking Employers Through Survey Years

Beginning in July 2013, the comprehensive "Employer History" roster has been made available to data users. This roster not only establishes links between employers through multiple survey years, but compiles a large amount of information about employers from one survey year to another into a single record for each employer. For further information about the Employer History roster, see Appendix 28: Employer History Roster.

It is still possible for users to link the respondents' employers from each contiguous survey year to the next using the traditional method. This appendix describes the traditional job linking process.

Comparable variables exist for each employer in all survey years, allowing a link to be established through all contiguous interview years during which the respondent reported working for a specific employer.

Use the variables with question names beginning with "PREV_EMP." All of these previous employer variables have a reference number that begins with "W." For example, the variables listed below in Table 1 relate to employers reported during the 1990 interview.

Table 1. Variables identifying job number assigned in previous interview

Reference #
Qname Variable Title
W05057.00  PREV_EMP#_1990_JOB#01 PREVIOUS JOB NUMBER AT LAST INTERVIEW, JOB 1, 1990
W05058.00  PREV_EMP#_1990_JOB#02 PREVIOUS JOB NUMBER AT LAST INTERVIEW, JOB 2, 1990
W05059.00 PREV_EMP#_1990_JOB#03    PREVIOUS JOB NUMBER AT LAST INTERVIEW, JOB 3, 1990
W05060.00 PREV_EMP#_1990_JOB#04 PREVIOUS JOB NUMBER AT LAST INTERVIEW, JOB 4, 1990
W05061.00 PREV_EMP#_1990_JOB#05 PREVIOUS JOB NUMBER AT LAST INTERVIEW, JOB 5, 1990

These variables identify the number that a job was assigned in the previous interview year, if that job was reported. If these variables contain a valid missing code (-4), then the job was not reported in the previous interview year (1989) and therefore cannot be linked to any employer in the previous year. This is essentially a "new" employer, reported for the first time during the current survey year (or possibly an employer reported before the previous interview). If any of these variables contains a valid number (1 or greater), this is the number of that job in the previous interview year. For example, if W05057.00 contains a "2", this would mean that employer #1 in 1990 is the same employer as employer #2 from 1989. One could then attach information from employer #1 in 1990 to information from employer #2 in 1989 as a continuing record of the respondent's experience with that employer. Using corresponding variables through contiguous interview years, information for an employer can be traced back through the first time the employer was ever reported by the respondent.

Of course, forward linking of employers can be accomplished in much the same way, using the same set of Previous Employer variables. For instance, to link information about employer #2 in 1989 with its continuation in 1990, one would search the 1990 Previous Employer Number variables for the number"2." Thus, a "2" in variable W0505900 would indicate that employer #3 in 1990 is the continuation of employer #2 from 1989.

This procedure works through contiguous survey years, even if the respondent has skipped interviews and the survey years are not consecutive. For example, if a respondent was interviewed in all years from 1985-1990, a direct match can not be made between an employer reported in 1990 and one reported in 1985 without first establishing matches (or the lack thereof) through all intervening years. However if a respondent was interviewed in 1985, and not again until 1990, a link between employers reported in these two years would be accomplished in the same manner as that described above between 1989 and 1990, as there would be no intervening year(s) to interfere with a direct match.

User Notes

Users should be aware of several data characteristics:

First, the NLSY79 employment history data are employer based. All references to a "job" should be understood as a reference to an employer. Information about work duties and positions and/or changes in duties or position performed or held during the respondent's tenure with a specific employer is collected as part of the record for that specific employer. For example, a respondent may regard him/herself as having held a number of "jobs" or positions with employer #1. However, any information collected about these different positions would all be regarded as information about employer #1.

The data for many survey years contain multiple versions of the PREVIOUS JOB NUMBER variables for employer matching. However, the PREVIOUS JOB NUMBER variables are compiled as part of the Work History programming and (as signified by reference numbers beginning with "W" consolidate this information into a single item for each employer for each survey year. Examples of these for 1990 are listed above in Table 1.

In the course of creating the Employer History roster mentioned earlier, a new more comprehensive version of the unique id was created for each job ever reported. These variables are called "EMPLOYERS_ALL_UID." These new unique employer ids are present for all jobs reported by all respondents since 1979. While these ids will usually match the id described in the paragraph above, they will not always match. Users should consider using the EMPLOYERS_ALL_UID.## variables wherever necessary, as these will generally be more consistent and available for all jobs.

This unique identification number consists of the first survey year in which the employer was reported, appended with the employer number in that survey year multiplied by 100. So for instance, an employer first reported as employer #1 in 1993 would have a unique employer id of 19930100. An employer first reported as employer #3 in 1994 would have the unique employer id of 19940300, and so on. This id number stays with the employer in subsequent survey rounds, whether or not more information is added to the employer record.

Users should note that previous versions of "unique ids" for employers were only available for respondents still eligible for interview in 1996 and subsequent survey years.