Technical Note
The estimates in this release are based on annual average data obtained
from the Current Population Survey (CPS). The CPS is a monthly survey of
about 60,000 households that is conducted by the U.S. Census Bureau for
the Bureau of Labor Statistics (BLS).
Questions were added to the CPS in June 2008 to identify persons with
a disability in the civilian noninstitutional population age 16 and older.
The addition of these questions allowed the Bureau of Labor Statistics to
begin releasing monthly labor force data from the CPS for persons with a
disability. The collection of these data is sponsored by the Department
of Labor's Office of Disability Employment Policy.
Information in this release will be made available to sensory-impaired
individuals upon request. Voice phone: (202) 691-5200; Federal Relay Ser-
vice: (800) 877-8339.
Reliability of the estimates
Statistics based on the CPS are subject to both sampling and nonsam-
pling error. When a sample, rather than the entire population, is sur-
veyed, there is a chance that the sample estimates may differ from the
"true" population values they represent. The exact difference, or sam-
pling 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 of con-
fidence.
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.
In addition, unlike other CPS data, the estimates of the population
of persons with a disability are not controlled to independent popula-
tion totals because such data are not currently available. Without con-
trols, estimates are more apt to vary in unpredictable ways from one
month to the next. Additionally, the labor force estimates for persons
with disabilities have not been seasonally adjusted due to the fact that
these data have been collected for a few months only. Typically, several
years worth of monthly estimates are required before seasonally adjusted
estimates can be produced.
A full discussion of the reliability of data from the CPS and informa-
tion on estimating standard errors is available online at www.bls.gov/cps/
documentation.htm#reliability.
Disability questions and concepts
The CPS uses a set of six questions to identify persons with disabili-
ties. In the CPS, persons are classified as having a disability if there
is a response of "yes" to any of these questions. The disability questions
appear in the CPS in the following format:
This month we want to learn about people who have physical, mental, or
emotional conditions that cause serious difficulty with their daily acti-
vities. Please answer for household members who are 15 years and older.
--Is anyone deaf or does anyone have serious difficulty hearing?
--Is anyone blind or does anyone have serious difficulty seeing
even when wearing glasses?
--Because of a physical, mental, or emotional condition, does anyone
have serious difficulty concentrating, remembering, or making
decisions?
--Does anyone have serious difficulty walking or climbing stairs?
--Does anyone have difficulty dressing or bathing?
--Because of a physical, mental, or emotional condition, does anyone
have difficulty doing errands alone such as visiting a doctor's
office or shopping?
The CPS questions for identifying individuals with disabilities are
only asked of household members who are age 15 and older. Each of the
questions ask the respondent whether anyone in the household has the
condition described, and if the respondent replies "yes," they are then
asked to identify everyone in the household who has the condition. Labor
force measures from the CPS are tabulated for persons age 16 and older.
More information on the disability questions and the limitations of the
CPS disability data is available on the BLS Web site at www.bls.gov/cps/
cpsdisability_faq.htm.
Other definitions
Other definitions used in this release are described briefly below.
Additional information on the concepts and methodology of the CPS is
available at www.bls.gov/cps/documentation.htm.
Employed persons are all those who, during the survey reference week
(which is generally the week including the 12th day of the month), (a)
did any work at all as paid employees; (b) worked in their own business,
profession, or on their own farm; (c) worked 15 hours or more as unpaid
workers in a family-operated enterprise; or (d) were temporarily absent
from their jobs because of illness, vacation, labor dispute, or another
reason.
Unemployed persons are all persons who had no employment during the
reference week, were available for work, except for temporary illness,
and had made specific efforts to find employment sometime during the 4
weeks preceding the survey. Persons who were waiting to be recalled to
a job from which they had been laid off need not have been looking for
work to be classified as unemployed.
Civilian labor force comprises all persons classified as employed
or unemployed.
Unemployment rate represents the number of unemployed persons as a
percent of the civilian labor force.
Not in the labor force includes all persons who are not classified
as employed or unemployed. Information is collected on their desire
for and availability to take a job at the time of the CPS interview,
job search activity in the prior year, and reason for not looking in
the 4-week period prior to the survey week. This group includes in-
dividuals marginally attached to the labor force, defined as persons
not in the labor force who want and are available for a job and who
have looked for work sometime in the past 12 months (or since the end
of their last job if they held one within the past 12 months). They
are not counted as unemployed because they had not actively searched
for work in the prior 4 weeks. Within the marginally attached group
are discouraged workers--persons who are not currently looking for
work because they believe there are no jobs available or there are
none for which they would qualify. The other persons marginally at-
tached to the labor force group includes persons who want a job but
had not looked for work in the past 4 weeks for reasons such as family
responsibilities or transportation problems.
At work part time for economic reasons, a measure sometimes referred
to as involuntary part time, refers to individuals who gave an economic
reason for working 1 to 34 hours during the reference week. Economic
reasons include slack work or unfavorable business conditions, inabil-
ity to find full-time work, and seasonal declines in demand. Those who
usually work part time must also indicate that they want and are avail-
able for full-time work.
Occupation, industry, and class of worker for the employed relate
to the job held in the survey reference week. Persons with two or more
jobs are classified in the job at which they worked the greatest number
of hours. Persons are classified using the 2002 Census occupational and
2007 Census industry classification systems. The class-of-worker break-
down assigns workers to the following categories: Private and government
wage and salary workers, self-employed workers, and unpaid family workers.
Wage and salary workers receive wages, salary, commissions, tips, or pay
in kind from a private employer or from a government unit. Self-employed
persons are those who work for profit or fees in their own business, pro-
fession, trade, or farm. Only the unincorporated self-employed are in-
cluded in the self-employed category. Self-employed persons who respond
that their businesses are incorporated are included among wage and salary
workers because, in a legal sense, they are paid employees of a corpora-
tion.
United States Department of Labor
