Technical Note
The estimates in this news release are based on annual average data from the Current
Population Survey (CPS). The CPS, which is conducted by the U.S. Census Bureau for
the Bureau of Labor Statistics (BLS), is a monthly survey of about 60,000 eligible
households that provides information on the labor force status, demographics, and
other characteristics of the nation's civilian noninstitutional population age 16
and over. In response to the increased demand for statistical information about the
foreign born, questions on nativity, citizenship, year of entry into the United
States, and the parental nativity of respondents were added to the CPS beginning in
January 1994. Prior to 1994, the primary sources of data on the foreign born were
the decennial census, two CPS supplements (conducted in April 1983 and November 1989),
and, to some extent, information collected by the U.S. Citizenship and Immigration
Services (formerly known as the Immigration and Naturalization Service).
The foreign- and native-born data for 2011 are not strictly comparable with data for
2010 and earlier years because of the introduction in January 2011 of revised population
controls used in the CPS. The effect of the revised population controls on the foreign-
and native-born estimates is unknown. However, the effect of the new controls on the
monthly CPS estimates was to decrease the December 2010 employment level by 472,000 and
the unemployment level by 32,000. The updated controls had little or no effect on unem-
ployment rates and limited effects on other ratios. Additional information is available
from the BLS website at www.bls.gov/cps/documentation.htm#pop.
Information in this news release will be made available to sensory impaired individuals
upon request. Voice phone: (202) 691-5200, Federal Relay Service: (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 upon 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 confidence.
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 pro-
cessing of the data.
A full discussion of the reliability of data from the CPS and information on estimating
standard errors is available at www.bls.gov/cps/documentation.htm#reliability .
Definitions
Definitions of the principal terms used in this news release are presented below.
Foreign born. The foreign born are persons residing in the United States who were not
U.S. citizens at birth. That is, they were born outside the United States or one of its
outlying areas such as Puerto Rico or Guam, to parents neither of whom was a U.S. citizen.
The foreign-born population includes legally-admitted immigrants, refugees, temporary
residents such as students and temporary workers, and undocumented immigrants. The survey
data, however, do not separately identify the number of persons in these categories.
Native born. The native born are persons born in the United States or one of its
outlying areas such as Puerto Rico or Guam or who were born abroad of at least one parent
who was a U.S. citizen.
Race and ethnicity groups. In this release, the data are presented for non-Hispanic
whites, blacks, and Asians and for persons of Hispanic or Latino ethnicity. These four
groups are mutually exclusive but not exhaustive. Other race groups (including persons
who selected more than one race category) are included in the overall totals but are
not shown separately because the number of survey respondents is too small to develop
statistically reliable estimates. The presentation of the data on race and ethnicity in
this release differs from that which appears in most analyses of CPS labor force data
because persons of Hispanic or Latino ethnicity are separated from the race groups.
Because persons of Hispanic or Latino ethnicity can be of any race, they are usually
included in the race groups as well as shown separately in the Hispanic or Latino
ethnicity group. The reason for the difference in the data presentation in this release
is because about half of the foreign born are of Hispanic or Latino ethnicity and they
have somewhat different labor force characteristics than the non-Hispanic foreign born.
Employed. Employed persons are (a) all those who, during the survey reference week,
did any work at all as paid employees, worked in their own business, profession, or on
their own farm, or who worked 15 hours or more as unpaid workers in a family-operated
enterprise; and (b) all those who did not work but had jobs or businesses from which
they were temporarily absent due to illness, bad weather, vacation, childcare problems,
labor disputes, or personal reasons, whether or not they were paid for the time off and
whether or not they were seeking other jobs.
Unemployed. The unemployed are persons who had no employment during the reference week,
were available for work at that time, except for temporary illness, and had made specific
efforts to find employment sometime during the 4-week period ending with the reference
week. Persons who were waiting to be recalled to a job from which they had been laid off
need not be looking for work to be classified as unemployed.
Civilian labor force. The civilian labor force comprises all persons classified as
employed or unemployed.
Unemployment rate. The unemployment rate is the number unemployed as a percent of the
civilian labor force.
Labor force participation rate. The labor force participation rate is the labor force
as a percent of the population.
Usual weekly earnings. Data represent earnings before taxes and other deductions and
include any overtime pay, commissions, or tips usually received (at the main job in the
case of multiple jobholders). Earnings reported on a basis other than weekly are converted
to a weekly equivalent.
Full-time wage and salary workers. These are workers who usually work 35 hours or
more per week at their sole or principal job and receive wages, salaries, commissions,
tips, payment in kind, or piece rates. The group includes employees in both the private
and public sectors but, for purposes of the earnings series, excludes all self-employed
persons, regardless of whether or not their businesses are incorporated.
Median earnings. The median is the amount which divides a given earnings distribution
into two equal groups, one having earnings above the median and the other having earnings
below the median.
