4.29 Work Experience

Chapter 4 contents

Although the NLS has collected information on labor force behavior since its inception, only partial work histories can be constructed for respondents for certain survey years. The degree of completeness of the work history data varies by survey year.

For those wishing to measure labor force attachment over time, three approaches are available. One can examine (1) the amount of time in weeks that a respondent spent working, unemployed (looking for work), or out of the labor force; (2) the start and stop dates of each job a respondent has held (i.e., a continuous job history); or (3) the start and stop dates associated with each employer for whom a respondent worked (i.e., a continuous employer history).

In general, summary weeks data (i.e., information on the number of weeks working, weeks unemployed, and weeks out of the labor force) were collected during each interview for either the previous 12 months or the previous calendar year. The term "summary weeks data" refers to the respondent's answers (in weeks) to the following types of questions: "During the past 12 months, in how many different weeks did you do any work at all?" Respondents who worked 52 weeks were asked: "Did you lose any full weeks of work during the past 12 months because you were on layoff from a job or lost a job?" Respondents who worked less than 52 weeks were asked: "In any of the remaining weeks, were you looking for work or on layoff from a job?" Those responding "yes" were asked: "How many weeks?" Respondents who did not work during the past 12 months were asked if they had spent any time looking for work or on layoff and if they had, how many weeks. While placement and wording of the individual questions have varied, this core set of summary questions was always present in each interview.

Unfortunately, such data collection consistency did not occur in obtaining information to track all job and/or all employer changes. The gaps in information collected on weeks worked (see discussion below) are minor compared to the gaps in information on jobs held and employment spells. Due to the fact that personal and telephone interviews used different time reference periods, it is only possible to construct a complete job and/or employer record for the later years of the survey.

There are three different ways to construct a summary measure for number of weeks worked, seeking work, or out of the labor force. Users can examine the start and stop dates associated with each job, especially in the personal interview years, when the questionnaire included a detailed work history in a column format. (The titles for these variables can be found on the data file by searching for the words "Most Recent Job.") When the information about start and stop dates is combined, a fairly complete picture of total number of weeks in the labor force can be pieced together. This is the usual procedure that has been used by NLS staff to create the *KEY* weeks variables. Users attempting to create number of weeks worked themselves instead of using the created *KEY* variables need to pay close attention to the skip patterns followed in the early survey years. Many check items send respondents to different parts of the questionnaire to respond to questions worded specifically for their particular situations. When constructing number of weeks worked, users should pay particular attention to the dates in the detailed work history section. During the early survey years, the Census Bureau truncated the date the respondent started the job to the preceding interview date if it started before then, so the actual starting date may not be available; in the later years, when an interviewer inadvertently went back before the date of the last interview and gathered information before that date, this information was sometimes left on the data file instead of being blanked out and eliminated.

Two alternatives to this time-consuming procedure of piecing the record together from start and stop dates include (1) use of information from the summary weeks questions present in the questionnaire for all years through 1992 or (2) a combination of data from (a) the *KEY* summary weeks variables for those years in which they were constructed and (b) information from the summary weeks questions for those years in which no *KEY* variable is available. The *KEY* variables (e.g., those variables with titles of '# OF WEEKS WORKED [reference period] *KEY*,' '# OF WEEKS UNEMPLOYED [reference period] *KEY*,' and '# OF WEEKS OLF [reference period] *KEY*') were created for those survey years in which respondents were personally interviewed. Care should be taken to check that the number of cases on the summary weeks variables is reasonably close to the number of respondents interviewed (since all respondents should have a value on these variables). If this is not the case, the user needs to make sure that the desired information is not present in another part of the questionnaire or to adjust for the fact that in some years respondents who had not worked since the last interview were assigned to "missing" instead of being assigned a "zero" for zero weeks of work, as one would expect.

Gaps in the reference periods for the summary week variables occur in the early 1970s when the project phased in an alternating personal and telephone interview pattern. The regularly fielded personal interviews conducted during the early survey years gave way to a 2-2-1 interview pattern (i.e., two telephone interviews occurring two years apart followed by a personal interview at the end of the five-year period). The intent of the telephone interview was to obtain a brief update of information on each respondent and to maintain sufficient contact such that the lengthier personal interview could be completed. Due to the fact that the reference period for the summary weeks questions within a telephone interview was the previous 12 months and that no interview was conducted the year before each telephone survey, gaps in the summary weeks record occurred.

The discussion below reviews the types of summary weeks information that are available from the questionnaire. Included is information on changes in the reference periods for which these data were collected. The weeks worked accounting is not completely accurate due to the slight over- or under-counting of weeks that occurred when a respondent was not interviewed exactly one year from the date of the last interview. If the respondent accurately answered the question on how many weeks in the last 12 months she worked and it had been 13 months since the last interview, the summary weeks variables would miss four weeks of employment status information. Census was asked in the early years to interview each respondent as close as possible to the date of the previous interview; the actual dates of interview can and should be checked.

The 1967 survey collected information from respondents not currently working on the specific year that they last worked. Responses were coded into the following categories: "never worked at all," "never worked two or more weeks," the (specific) year worked if before 1962, the (specific) month and year if employment occurred between 1962 and 1965, or a residual category indicating that the last time worked was January 1966 or later. All respondents were asked the summary weeks questions on number of weeks worked, weeks unemployed, and weeks out of the labor force for the previous calendar year (i.e., 1966).

Respondents were filtered through a detailed section on work experience before 1966, with different questions depending on marital status and fertility. Respondents who had been married or were currently married and had children were asked for information on the longest job held between the time they stopped attending school and their (first) marriage, the longest job held between the time they married and had their first child, and the longest job held since the birth of their first child. Respondents who were married and who had no children were asked for information on the longest job held between the time they stopped attending school and their (first) marriage, and the longest job held since their (first) marriage. Those who had never married and who had no children were asked for information on the first job in which they worked six months since attending school full-time and the longest job ever held since they stopped attending school full-time. The never-married group with children was asked for information on the longest job held between the time they stopped attending school and the birth of their first child, and the longest job held since that child's birth. Each of these groups was also asked a global question on how many years since these benchmark events they had worked at least six months. A series of created variables (R00744.05-R00744.50) presents this information.

The 1968 survey was a mail interview in which all respondents were asked for information on the job they held last week; the summary weeks questions covered the past 12 months. In the 1969 interview, those respondents who were currently working or who had held a job since June 1, 1968, were asked about that job; summary weeks questions again refer to the last 12 months.

In 1971, the current or last job, the detailed work history section, and the summary weeks questions each used the date of the previous interview as the reference period. In the 1972 survey, the 1971 pattern was repeated. Except for respondents who were not interviewed in all years, fairly accurate total number of weeks worked, unemployed, or out of the labor force variables can be constructed for 1966-72.

The gaps in the summary weeks information began with the 1974 telephone interview. Data on the current or last job were collected back to the date of the previous interview; however, the summary weeks questions only asked about the previous 12-month period. The 1976 telephone interview followed the 1974 pattern.

The 1977 personal interview collected information for those respondents who had worked since the date of the 1976 interview (or April 4, 1976, if the respondent was not interviewed in 1976) on the current or last job and detailed work history. The summary weeks questions were asked of all respondents for the period "since 1976." Respondents were also asked for information on the longest job held since June 1972.

The 1979 telephone interview referred to the date of the 1977 interview (or April 15, 1977, if the respondent was not interviewed in 1977) for the current or last job and to the previous 12 months for the summary weeks questions. A new type of question (item 12d) obtained information on the number of weeks worked for the 12-month period previous to the last 12 months. Answer categories are numbered "1" through "4" with "1" meaning that the respondent worked most of the year (46-52 weeks), "2" meaning that she had worked more than half a year (26-45 weeks), "3" meaning that she had worked less than half a year (1-25 weeks), and "4" meaning she had not worked at all. By using the midpoint and assigning zero weeks to those respondents who did not work at all, users can approximate the number of weeks worked, although one cannot distinguish between those unemployed and those out of the labor force. The 1981 telephone interview repeated the 1979 pattern.

The 1982 personal interview repeated the 1977 pattern. Respondents were asked for information about both their current or last job and all other jobs held since the date of the 1981 interview (or since April 5, 1981, if the respondent was not interviewed in 1981). The reference period for the summary weeks questions was the last 12 months. For those respondents who had not worked since the last interview, information on weeks unemployed and weeks out of the labor force was collected using item 6. When using the items from the questionnaire to construct weeks worked, users should note that item 21 is bounded differently than usual. Because researchers were running into inconsistencies trying to create summary measures over time, a set of questions dealing with the number of years worked since the respondent was 18 years old was added to this questionnaire. Items 41a through 41c gather information on the number of years since she was 18 that a respondent held a job at all, in how many of those years she worked six months or more, and, of those years, how many she usually worked at least 35 hours per week.

The 1984 telephone interview referred to the date of the 1982 interview (or August 1, 1982, if the respondent was not interviewed in 1982) for the current or last job. Two sets of summary weeks questions referred to the last 12 months and the 12-month period previous to that. Unlike the 1979 and 1981 questions, the answer categories were actual weeks; by using item 12e, one can separate out weeks unemployed from weeks out of the labor force. Items 5c and 5d provide similar information on respondents who had not worked at all since the date of their last interview. Variables need to be created to combine this information for all interviewed respondents.

The 1986 telephone interview referred back to the date of the 1984 interview (or May 5, 1984, if the respondent was not interviewed in 1984) for the current or last job. Two sets of summary weeks questions referred to the last 12 months and the 12-month period previous to that. For those who had not worked at all since 1984, the weeks unemployed and weeks out of the labor force information was collected using items 5b through 5d. Variables need to be created to combine this information for all interviewed respondents.

The 1987 personal interview repeated the 1982 pattern. Respondents were asked about their current or last job and about all employers (not jobs) for whom they had worked since the date of the 1986 interview (or since August 5, 1986, if the respondent was not interviewed in 1986). The focus of the detailed work history section was deliberately changed, and the lead-in question was revised to ask about employers (not jobs) for whom the respondent had worked three or more consecutive months. This year was one of two years (1987 and 1989) that information was collected on all employers for whom the respondent had worked for three or more consecutive months; in all other years respondents are asked about all jobs, regardless of tenure. Summary information was collected for the last 12-month period in items 26a through 26c. For those respondents who had not worked since the previous interview, information on weeks unemployed and out of the labor force can also be found in items 26a through 26c.

The 1989 survey was also a personal interview due to a BLS decision to eliminate the 2-2-1 pattern and field a personal interview every other year. Respondents were asked for information on both their current or last job and on all employers (not jobs) for whom the respondent had worked for three or more consecutive months since the date of the 1987 interview (or since August 15, 1987, if the respondent was not interviewed in 1987). Summary weeks information was collected for the period since the 1987 interview.

The 1992 personal interview included questions on the respondent's current or last job and on all employers for whom the respondent had worked since the date of the 1989 interview (or since the date of last interview, for those not interviewed in 1989). The detailed work history questions were asked about all employers for whom the person had worked since the last interview. Because this change in the reference date back to the previous interview coincided with changes in rules about dropping respondents after two years of noninterview, Census interviewed some respondents whose last interview occurred in the mid-1980s. Certain respondents will consequently have work histories that go back past 1989. The summary weeks questions cover the three-year gap in one-year increments.

The 1995-2003 personal interviews asked respondents about the start and stop dates of their current/last job and any intervening jobs. These start and stop dates were used--in conjunction with their reason for not working--to create summary weeks variables.

Survey Instruments: The work experience data are collected in the "Work History," "Employment," "Work Experience," "On Jobs," or "Employer Supplement" sections of the questionnaire in various survey years.

Created Work History Variables

The 1999, 2001, and 2003 data releases included a new set of week-by-week employment status variables for the CAPI/CATI interview years. Beginning with the first week of 1994 and continuing through the respondent's most recent interview date, a variable for each week indicates whether the respondent was working (coded "1") or not working (coded "0") that week. A summary variable for each year totals the number of weeks that the respondent worked. These variables can be located on the data files by searching for their question names as follows:

NCV-WORK-xx-01 to NCV-WORK-xx-52 (working/not working each week of year 19xx)
NCV-WORKxx (total weeks working in year 19xx)

Missing data are treated in the following manner: If the job start or end year is provided, an unknown or missing day is set to 15, and an unknown or missing month is set to 1 (January). Missing years are not imputed. If days provided are inconsistent for a given month (e.g., April 31), the day is reset to the closest consistent day (April 30). More information is available in Appendix 41 in the Codebook Supplement (PDF).

Descriptive Tables

The tables below present information on sample sizes by race and interview year for weeks worked and number of employers. For the purposes of these tables, the racial category "non-blacks" includes both whites and all other non-black races. Labels in the year columns refer to the survey year in which these data were collected, not to the reference period of the variable. "AVG WKS" means average number of weeks; "NO WORK" means the respondent reported no weeks of work; and "MISSING" means the respondent is a noninterview or an invalid skip for that particular survey year.

Tables 4.29.1 and 4.29.2 report the average overall number of weeks that respondents worked, with Table 4.29.1 depicting years before the CAPI instrument was used (1967-1993) and Table 4.29.2 showing data received during CAPI years. (The advent of CAPI provided the ability to collect a more complete respondent work history, so pre-CAPI and CAPI years are presented separately to avoid inaccurate comparisons.) In Tables 4.29.3 and 4.29.4, employment information is broken down (pre-CAPI and CAPI) by years the respondent reported a positive number of weeks worked.  Tables 4.29.5 and 4.29.6 include working versus nonworking respondents.

A number of decisions were made during the construction of these tables. The tables are not weighted and should not be used to make inferences about populations. Years in which the *KEY* or summary week variables were found to have an upper range greater than 52 were truncated to 52. In those years that a *KEY* variable covers a two-year period, the total number of weeks was divided by two.

The weeks tables do not take into account whether or not the respondent was really in the labor force; if a respondent was interviewed and did not report any weeks worked, she was assigned a "zero" even if, for example, she was permanently handicapped and would not have been in the labor force under normal conditions.

Table 4.29.1 Average Number of Weeks Worked 1967-1992 by Race (Unweighted)

Table 4.29.2 Average Number of Weeks Worked Calendar Years 1994-2002 by Race (Unweighted)

Table 4.29.3 Average Number of Weeks Worked 1967-1992 by Number of Years Reported Working and Race (Unweighted)

Table 4.29.4 Average Number of Weeks Worked Calendar Years 1994-2002 by Number of Years Reported Working and Race (Unweighted)

Table 4.29.5 Weeks Worked 1967-1992 by Survey Year and Race (Unweighted)

Table 4.29.6 Weeks Worked 1994-2002 by Calendar Year and Race (Unweighted)