U.S. Bureau of Labor Statistics
Workers on Flexible and Shift Schedules Technical Note
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These data and other information on work schedules were obtained from a
supplement to the May 2004 Current Population Survey (CPS). The CPS is a
monthly sample survey of about 60,000 households conducted by the U.S.
Census Bureau for the Bureau of Labor Statistics (BLS), principally to gather
information on employment and unemployment for the nation. Respondents to
the May 2004 supplement answered questions about flexible and shift sched-
ules, the reasons for working particular shifts, the beginning and ending
hours of work, formal flexitime programs, home-based work, and other related
topics. The data in this release cover the incidence and nature of flexible
and shift schedules and pertain to wage and salary workers who usually worked
35 hours or more per week on their principal job. The data exclude all self-
employed persons, regardless of whether or not their businesses were incorp-
The May 2001 data presented in this release have been revised to reflect the
introduction of Census 2000-based population controls and thus may differ from
previously published estimates which were based on population controls derived
from the 1990 census. The introduction of the Census 2000-based population
controls increased the May 2001 employment levels but had relatively little
impact on proportions and percents derived from the employment levels. Sample
results from the CPS are weighted up to independent estimates of the population
by sex, age, race, and Hispanic or Latino/non-Hispanic ethnicity. The weights,
or population controls, are developed using counts of the civilian noninstitu-
tional population derived from the decennial census and are updated using
information from administrative records.
Information in this release will be made available to sensory impaired
individuals upon request. Voice phone: 202-691-5200; TDD message referral
phone number: 1-800-877-8339.
Reliability of the estimates
Statistics based on the CPS are subject to both sampling and nonsampling
error. When a sample, rather than the entire population, is surveyed, there
is a chance that the sample estimates may differ from the "true" population
values they represent. The exact difference, or sampling error, varies
depending on the particular sample selected, and this variability is measured
by the standard error of the estimate. There is about a 90-percent chance,
or level of confidence, that an estimate based on a sample will differ by no
more than 1.6 standard errors from the "true" population value because of
sampling error. BLS analyses are generally conducted at the 90-percent level
The CPS data also are affected by nonsampling error. Nonsampling error
can occur for many reasons, including the failure to sample a segment of
the population, inability to obtain information for all respondents in the
sample, inability or unwillingness of respondents to provide correct
information, and errors made in the collection or processing of the data.
For a full discussion of the reliability of data from the CPS and for
information on estimating standard errors, see the "Explanatory Notes and
Estimates of Error" section of Employment and Earnings.
Data on flexible schedules, shift work, and beginning and ending hours
of work were obtained from the following questions:
Beginning and ending hours of work. At what time of day do you begin work
on your (main) job most days?
1. __hour __minutes A.M./P.M.
2. It varies
At what time of day do you end work on your main job most days?
1. __hour __minutes A.M./P.M.
2. It varies
Flexible schedules. Do you have flexible work hours that allow you to vary
or make changes in the time you begin and end work?
Formal flexitime programs. (If the respondent answers "yes" to the above
question on flexible hours, the following question is then asked.) Is your
flexible work schedule part of a flexitime or other program offered by your
Shift work. On your (main) job, do you usually work a daytime schedule or
some other schedule?
1. A daytime schedule (Anytime between 6 A.M. to 6 P.M.)
2. Some other schedule
(If the respondent answers "some other schedule" to the above question,
then the following question is asked to determine the shift worked.)
Which of the following best describes the hours you usually work at this
1. An evening shift (Anytime between 2 P.M. and midnight)
2. A night shift (Anytime between 9 P.M. to 8 A.M.)
3. A rotating shift--one that changes periodically from days to evenings
4. A split shift--one consisting of two distinct periods each day
5. An irregular schedule
6. Some other shift
Reason for alternative shift. What is the main reason why you work this
type of shift? (Interviewer reads all.)
1. Better arrangements for family or child care
2. Better pay
3. Allows time for school
4. Could not get any other job
5. Local transportation or pollution control program
6. Nature of the job
7. Personal preference
8. Some other reason
Last Modified Date: July 01, 2005