Number of Jobs Held, Labor Market Activity, and Earnings Growth Among the Youngest Baby Boomers: Results from a Longitudinal Survey Technical Note

Technical Note 
 
   The estimates in this release were obtained using data from the first 26 rounds of
the National Longitudinal Survey of Youth 1979 (NLSY79). This survey is conducted by
the Center for Human Resource Research at The Ohio State University and the National
Opinion Research Center at the University of Chicago under the direction and sponsorship
of the U.S. Department of Labor's Bureau of Labor Statistics. 
 
Sample 
 
   The NLSY79 is a nationally representative sample of 12,686 young men and women who
were 14 to 22 years of age when first surveyed in 1979. This survey sample was initially
composed of three subsamples: 
 
	--A cross-sectional sample of 6,111 youths that was designed to represent the
	  noninstitutionalized, civilian population of young people living in the U.S.
	  in 1979 and born between Jan. 1, 1957, and Dec. 31, 1964. 
 
	--A supplemental sample of 5,295 youths that was designed to oversample
	  non-institutionalized, civilian Black, Hispanic or Latino, and economically
	  disadvantaged non-Black, non-Hispanic or Latino youths living in the U.S.
	  in 1979 and born between Jan. 1, 1957, and Dec. 31, 1964. 
 
	--A military sample of 1,280 youths born between Jan. 1, 1957, and Dec. 31,
	  1961, and enlisted in the Army, Air Force, Navy, or Marine Corps as of
	  September 30, 1978. 
 
   In 1985, the military sample was discontinued, and, in 1991, the economically disadvantaged
non-Black, non-Hispanic or Latino youths were dropped from the supplemental sample. As a result,
the NLSY79 sample now includes 9,964 individuals from the cross-sectional sample and the Black
and Hispanic or Latino supplemental samples. (This sample size is not adjusted for sample
members who have died.) 

   Individuals were surveyed annually from 1979 to 1994 and biennially since 1994. In 2014-15,
7,071 individuals responded to the survey, for a retention rate of 71 percent (representing a
77 percent response rate among those sample members who are still living). Only these individuals
are included in the estimates in this release. All results are weighted using the 2014-15 survey
weights that correct for the oversampling, interview nonresponse, and permanent attrition from
the survey. When weighted, the estimates represent all persons born in the years 1957 to 1964 and
living in the U.S. when the survey began in 1979. Not represented by the survey are U.S.
immigrants who were born from 1957 to 1964 and moved to the U.S. after 1979. 

Work history data 
 
   The total number of jobs that people hold during their work life is an easy concept to
understand but a difficult one to measure. Reliable estimates require a survey that interviews
the same people over the course of their entire work life and also keeps track of all the
jobs they ever held. The NLSY79 tracks the number of jobs that people have held, but many
of the respondents in this survey are still in their prime working years, ages 49 to 58 in
2014-15, and have more years of work life ahead of them. As the cohort continues to age,
however, more complete information will become available. 

   A unique feature of the NLSY79 is that it collects the beginning and ending dates of
all jobs held by a respondent so that a longitudinal history can be constructed of each
respondent's work experiences. The NLSY79 work history data provide a week-by-week work
record of each respondent from Jan. 1, 1978, through the most recent survey date. These
data contain information on the respondent's labor force status each week, the usual hours
worked per week at all jobs, and earnings for all jobs. If a respondent worked at more than
one job in any week, hours and earnings are obtained for additional jobs. When a respondent
who missed one or more consecutive survey rounds is interviewed again, he or she is asked
to provide information about all time since the last interview. 
 
Interaction between time and age in a longitudinal survey  

   Because the NLSY79 is a longitudinal survey, meaning the same people are surveyed over
time, the ages of the respondents change with each survey round. It is important to
keep in mind this inherent link between the calendar years and the ages of the
respondents. For example, table 5 reports earnings growth from age 45 to age 50. The
youngest respondents in the sample (birth year 1964) were these ages during 2009-14,
whereas the oldest respondents (birth year 1957) were these ages during 2002-07. 

   Although participants in the NLSY79 were ages 49 to 58 during the 2014-15 interviews,
this release covers only the period while the respondents were ages 18 to 50. The reason
for not including older ages is that the sample sizes were still too small to provide
statistically reliable estimates for age groups older than 50. As the NLSY79 continues
to be administered and the respondents age, subsequent rounds of the survey will enable
analyses to be conducted for older age groups.

   As with age, the educational attainment of individuals may change from year to year.
In the tables and analysis presented in this report, educational attainment is defined
as of the 2014-15 survey. This definition is used even when data on age and educational
attainment are presented together. For example, table 1 reports the number of jobs held
during different age categories. Suppose that a respondent had completed a bachelor's
degree at age 40. That respondent would be included in the “Bachelor's degree and higher”
educational category in all age categories shown on the table, even though he or she
did not have a bachelor's degree at any point from age 18 to age 39. 
 
Definitions 
 
   Job. A job is defined as an uninterrupted period of work with a particular employer.
Jobs are therefore employer-based, not position-based. If a respondent indicates that
he or she left a job but in a subsequent survey returned to the same job, it is counted
as a new job. For example, if an individual worked in a retail establishment during the
summer, quit at the end of summer to return to school, and then resumed working for the
same employer the following spring, this sequence would count as two jobs, rather than
one. For self-employed workers, each “new” job is defined by the individuals themselves. 
 
   Unemployment. If respondents indicate a gap between employers, they are asked how many
of those weeks they spent searching for employment or on layoff. For that number of weeks,
they are considered unemployed. For the remaining weeks, they are coded as not in the labor
force. No probing for intensity of job search is done. 

   Usual earnings. Respondents can report earnings over any time frame (hour, day, week,
month, year). For those who do not report an hourly wage, one is constructed using usual
hours worked over that time frame. Wages greater than $100 per hour and less than $1 per
hour (in 1979 dollars) were not included in the analysis of earnings growth because the
reported earnings levels were almost certainly in error. For the same reason, individuals
who had inflation-adjusted earnings growth greater than 100 percent were not included in
the analysis. 
 
   Race and ethnicity groups. In this release, the findings are reported for non-Hispanic
or Latino Whites, non-Hispanic or Latino Blacks, and Hispanics or Latinos. These three
groups are mutually exclusive but not exhaustive. Other race groups, which are included in
the overall totals, are not shown separately because their representation in the survey
sample is not sufficiently large to provide statistically reliable estimates. In other BLS
publications, estimates usually are published for Whites, Blacks, and Hispanics or Latinos,
but these groups are not mutually exclusive. The term Hispanic or Latino is considered to
be an ethnicity group, and Hispanics or Latinos can be of any race. Most other BLS publications
include Hispanics or Latinos in the White and Black race groups in addition to the Hispanic
or Latino ethnicity group. 

Information in this release will be made available to sensory impaired individuals upon
request. Voice phone: (202) 691-5200; Federal Relay Service:  (800) 877-8339. 



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Last Modified Date: August 24, 2017