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Table of Contents

CONCEPTS ......................3

DATA SOURCES...............9

DESIGN...........................11

CALCULATION................14

PRESENTATION.............17

HISTORY.........................19

MORE INFORMATION....22

The Current Population Survey (CPS) is a monthly survey of U.S. households 

that is conducted by the U.S. Census Bureau for the U.S. Bureau of Labor 

Statistics (BLS).

The CPS is the source of the national unemployment rate, along with a wide 

range of information about employment, unemployment, and people not in the 

labor force.

Current Population Survey

Quick Facts: Current Population Survey

Subject areas Hours, Unemployment, Employment

Key measures

Labor force

Unemployment

Employment

Unemployment rate

Usual weekly earnings

How the data are obtained Survey of households

Classification system Demographic

Periodicity of data availability Monthly, Quarterly, Annual

Geographic detail National

Scope Civilian noninstitutional population
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Quick Facts: Current Population Survey

Key products

See the complete list of CPS news releases and 

reports online.

The Employment Situation

Usual Weekly Earnings of Wage and Salary

Workers

Employment Situation of Veterans

Labor Force Characteristics of People With

a Disability

Labor Force Characteristics of ForeignBorn Workers

Union Members

Employment Characteristics of Families

College Enrollment and Work Activity of

High School Graduates

Summer Employment and Unemployment

Among Youth

Employee Tenure

Worker Displacement

Monthly, quarterly, and annual tables

Program webpage www.bls.gov/cps
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Concepts

The Current Population Survey (CPS) is a monthly survey of U.S. households that is conducted by the U.S. 

Census Bureau for the U.S. Bureau of Labor Statistics.

The CPS is the source of the national unemployment rate, along with a wide range of information about 

employment, unemployment, and people not in the labor force.

Following are definitions of the key labor force concepts used in the CPS:

Civilian noninstitutional population. All people residing in the 50 states and the District of Columbia who are not 

confined to institutions such as nursing homes and prisons, and who are not on active duty in the U.S. Armed 

Forces. Included are citizens of foreign countries who reside in the United States but do not live on the premises of 

an embassy. The civilian noninstitutional population ages 16 and older is the base population group used for CPS 

statistics.

Civilian labor force, or labor force. All people ages 16 and older who are classified as either employed or 

unemployed, as defined below.

Labor force participation rate. The labor force (employed and unemployed people) as a percentage of the 

population. The labor force participation rate is calculated as (labor force ÷ civilian noninstitutional population) × 

100.

Employed people. All those who, during the survey reference week (generally, the week that includes the 12th day 

of the month), met any of the following criteria:

did any work at all as paid employees (a minimum of 1 hour)

worked in their own business or profession, or on their own farm

worked 15 or more hours as unpaid workers in a family member’s business

were temporarily absent from their jobs or businesses because of illness, vacation, bad weather, a labor 

dispute, or another reason (whether or not they were paid for the time off or were seeking other jobs)

Note that each employed person is counted only once, even if he or she holds more than one job. Excluded are 

people whose only activity consisted of work around their own home (such as housework, painting, repairing, and 

so forth) or volunteer activities for religious, charitable, or other organizations.

Employment–population ratio. The employed as a percentage of the population. The employment–population ratio 

is calculated as (employed ÷ civilian noninstitutional population) × 100.

Unemployed people. All people who meet all of the following criteria:

were not employed during the survey reference week

were available for work (except for temporary illness)
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had made a specific, active effort to find employment sometime during the 4-week period ending with the 

survey reference week

There is one exception to the active job search requirement: People waiting to be recalled to work while 

temporarily laid off do not need to look for a job in order to be classified as unemployed.

People waiting to start a new job must have actively looked for a job within the last 4 weeks in order to be 

classified as unemployed. Otherwise, they are classified as not in the labor force.

Active job search methods are defined as those which have the potential to result in a job offer without any further 

action on the part of the jobseeker. Examples of active job search methods are as follows:

contacting an employer directly about a job

having a job interview

submitting a resume or application to an employer or to a job website

using a public or private employment agency or university employment center

contacting friends or relatives, or seeking assistance through social networks

checking union or professional registers

placing or answering a job advertisement

some other active method

Methods that do not constitute active job search include simply looking at job postings without taking further action, 

and taking a training course.

Unemployment rate. The number of unemployed people as a percentage of the labor force. (The labor force is the 

sum of the employed and the unemployed.) The unemployment rate is calculated as (unemployed ÷ labor force) × 

100.

Not in the labor force. People ages 16 and older in the civilian noninstitutional population who are neither 

employed nor unemployed.

Information is collected on their desire for work and availability to take a job at the time of the CPS interview, their 

job search activity in the previous year, and their reason for not looking for work in the 4-week period ending with 

the survey reference week.

On the basis of this information, a subgroup known as those marginally attached to the labor force is identified. 

The marginally attached are people who want and are available for a job, and who have looked for work sometime 

in the previous 12 months (or since the end of their last job if they held one within the previous 12 months). They 

are not counted as unemployed because they had not actively searched for work in the previous 4 weeks.

The marginally attached are further divided into two subgroups:

Discouraged workers. The discouraged are not currently looking for work for reasons such as the following:

They believe that there are no jobs available to them, or none for which they would qualify.

They could not find work in the past.
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They lack the schooling or training needed for the jobs that are available.

They believe that employers think that they are too young or too old, or they believe that they are 

subject to other types of discrimination.

Their specific responses may vary somewhat, but the reasons they give all indicate discouragement about 

their job prospects.

Other people marginally attached to the labor force. This group includes all marginally attached people who 

are not classified as discouraged. They are people who want a job but had not looked for work in the past 4 

weeks for reasons such as family responsibilities, unavailability of childcare, transportation problems, or 

illness.

Usual full- or part-time status. People are classified as full- or part-time workers according to the number of hours 

they usually work per week.

Full-time workers are those who usually work 35 or more hours per week (at all jobs combined), regardless 

of their actual hours at work during the survey reference week. Thus, this group includes some individuals 

who, for various reasons, may have worked less than 35 hours in the reference week. It also includes 

people who were temporarily absent from work but who usually work at least 35 hours per week.

Part-time workers are those who usually work less than 35 hours per week (at all jobs combined), 

regardless of their actual hours at work during the survey reference week. This group, therefore, includes 

some individuals who actually worked 35 hours or more during the reference week, as well as some who 

were temporarily absent from work but who usually work less than 35 hours.

Hours at work. The measure that reflects a person’s actual hours at work during the survey reference week. For 

example, people who usually work 40 hours a week, but were off 8 hours on Columbus Day, would be reported as 

being at work 32 hours, even if they were paid for the holiday.

Data on hours worked pertain only to people who were at work for at least 1 hour during the survey reference 

week and exclude people who were not at work for the entire week. For people working in more than one job, the 

published figures relate to the number of hours worked in all jobs during the reference week.

At work part time for economic or noneconomic reasons. These measures pertain to people who were at work for 

1 to 34 hours during the survey reference week and exclude people who were not at work during the reference 

week.

At work part time for economic reasons. People who are at work part time for economic reasons, also 

referred to as involuntary part-time workers, are those who gave an economic reason for working 1 to 34 

hours during the survey reference week. They also must indicate that they want, and are available, to work 

full time in order to be classified into this category.

Economic reasons for working part time include the following:

slack work or unfavorable business conditions

inability to find full-time work

seasonal declines in demand
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At work part time for noneconomic reasons. This category of workers includes people who usually work part 

time and who gave a noneconomic reason for working 1 to 34 hours during the survey reference week. The 

group also includes a small number of people with an economic reason for working 1 to 34 hours but who 

were unavailable to work full time.

Noneconomic reasons for working part time are as follows:

illness or other medical limitations

childcare problems or other family or personal obligations

school or training

retirement or Social Security limits on earnings

being in a job in which full-time work is less than 35 hours

other reasons

Reasons for unemployment. Unemployed people (that is, people who are actively seeking and are available for 

work) are categorized by general reason for unemployment, based on their status at the time they began to look 

for work. There are four major categories:

Job losers consist of

people on temporary layoff who have been given a date to return to work or who expect to return 

within 6 months (people on temporary layoff need not be looking for work in order to be classified as 

unemployed)

permanent job losers (those whose employment ended involuntarily)

people who completed a temporary job

Job leavers are people who quit or otherwise voluntarily terminated their employment

Reentrants are people who previously worked but who were not in the labor force prior to beginning their 

most recent job search

New entrants are people who had never previously worked

Duration of unemployment. The length of time (up to and including the survey reference week) that people 

classified as unemployed had been continuously looking for work. For people on layoff, the duration of 

unemployment is the number of full weeks they have been on layoff.

Mean duration of unemployment is the arithmetic average of the duration of unemployment, computed from 

the number of single weeks of unemployment.

Median duration of unemployment is the midpoint of a distribution of the number of weeks of unemployment, 

where half of the unemployed workers had been looking for work longer than the median number of weeks 

and half had been looking for fewer weeks than the median.

The unemployment duration measures reflect still-in-progress spells of joblessness, not completed spells. The 

Current Population Survey does not ask how long it took someone to find a job, and the duration measures do not 

provide that information.

Occupation. The type of job or work that a person does, such as carpenter, software developer, or cashier. The 

CPS uses the Census Occupational Classification system, which is derived from the Standard Occupational 

Classification system (SOC).
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For the employed, the occupation is based on the job they held in the survey reference week. People with two or 

more jobs are classified as being in the job at which they worked the greatest number of hours. The unemployed 

are classified according to their last job.

Industry. This concept reflects the business activity of a person’s employer or company (manufacturing, retail 

store, hospital), regardless of the type of work that person does (his or her occupation). An industry includes 

people with different occupations who work for the same type of business.

For the employed, the industry is based on the job the worker held in the survey reference week. People with two 

or more jobs are classified as being in the job at which they worked the greatest number of hours. The 

unemployed are classified according to their last job.

Class of worker. A term used to describe general categories of employment arrangements. Workers are 

categorized into one of the following groups:

Wage and salary workers are those who receive wages, salaries, commissions, tips, or payment in kind 

from a private-sector employer or from a local, state, or federal government agency or entity.

Self-employed people are those who work for profit or fees in their own business, profession, trade, or farm. 

Typically, the term self-employed refers to the unincorporated self-employed. Self-employed people whose 

businesses are incorporated generally are included among wage and salary workers because, technically, 

they are paid employees of their corporation.

Unpaid family workers are people working without pay for 15 or more hours a week on a farm or in a 

business operated by a family member with whom they reside.

For the employed, the class of worker to which they belong is based on the job they held in the survey reference 

week. People with two or more jobs are classified into the job at which they worked the greatest number of hours. 

The unemployed are classified according to their last job.

Multiple jobholders. Employed people who had two or more jobs during the survey reference week.

To be classified as a multiple jobholder, the individual must have been a wage and salary worker (defined above) 

in at least one of the jobs he or she held. Self-employed people with multiple unincorporated businesses and 

people with multiple jobs as unpaid family workers are not classified as multiple jobholders.

A person employed only in private households (such as a cleaner, gardener, or babysitter) who worked for two or 

more employers during the survey reference week is not counted as a multiple jobholder.

Usual weekly earnings for wage and salary workers. The usual weekly earnings data from the CPS 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 (such as annual, monthly, or hourly) are converted to weekly. The 

term usual is determined by each respondent’s own understanding of it. If the respondent asks for a definition of 
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“usual,” interviewers are instructed to define the term as more than half the weeks worked during the past 4 or 5 

months.

CPS earnings data reflect the sole or primary job of wage and salary workers, and exclude all self-employed 

people, whether or not their businesses are incorporated. Earnings data are collected about employed people only. 

The survey does not ask how much unemployed people earned on their last job.

Median usual weekly earnings. The median earnings level is the midpoint in a given earnings distribution, with half 

of workers having earnings above the median and the other half having earnings below the median. Published 

estimates of medians are calculated by linear interpolation of the $50 centered interval within which each median 

falls.

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Data Sources

Approximately 60,000 scientifically selected households make up the Current Population Survey (CPS) sample. 

Each month, U.S. Census Bureau interviewers attempt to contact a responsible person in each of these eligible 

households to complete a CPS interview. The Census Bureau will contact each household for 8 monthly interviews 

over a 16-month period. (See Rotation of Sample in the Design section).

The first time a household is surveyed, the interviewer prepares a roster of the resident household members that 

includes some of their personal characteristics, such as date of birth, race, Hispanic or Latino ethnicity, marital 

status, educational attainment, and veteran status.

For each household in the survey, there is a designated “householder”: the person, or one of the people, who rents 

or owns the residence. The designation “householder” is used in the roster to identify each household member’s 

relationship to the householder: spouse, child, domestic partner, etc. The roster is checked for accuracy and 

brought up to date at each subsequent interview to take account of new or departed household residents, changes 

in marital status, and similar items.

Personal visits are typically required the first month the household is in the sample, and they are preferred in the 

fifth month. In other months, interviews generally are conducted by telephone. Households without a telephone 

and those which specifically request a personal visit usually receive in-person interviews each month. About 10 

percent of eligible households are interviewed via computer-assisted telephone interviewing (CATI) from telephone 

centers located in Jeffersonville, Indiana, and Tucson, Arizona. Field representatives interview the remaining 

households (approximately 68 percent of households in any given month) by telephone.

At each monthly interview, a series of standard questions on work and job search activities during the reference 

week is asked about each household member 15 years of age or older. The reference week is generally the week 

that includes the 12th of the month, and Census Bureau interviewers usually begin collecting data during the week 

that includes the 19th of the month.

On the basis of responses to these questions, the sample population is classified into 1 of 3 groups: the employed,

the unemployed, and those not in the labor force. After the basic labor force questions are asked, most monthly 

interviews include an additional set of questions on supplemental topics, such as school enrollment, income and 

health insurance, and characteristics of military veterans.

At the end of each day’s interviewing, the field representative transmits the collected data to the Census Bureau’s 

central computer outside Washington, DC. Once files are transmitted to the main computer, they are deleted from 

the interviewers’ laptops.

Because of the crucial role interviewers have in the CPS, a great amount of time and effort is spent maintaining the 

quality of their work. Interviewers are given intensive training, including classroom lectures, discussion, practice, 

observation, home-study materials, and on-the-job training. Interviewers receive self-study training each month, as 
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well as periodic refresher training sessions. They also are periodically accompanied by a supervisor during a full 

day of interviewing to determine how well they carry out their assignments.

A selected number of households are reinterviewed each month to detect and deter falsification by interviewers. 

These reinterviews are conducted by a dedicated staff operating independently of the CPS management structure.

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Design

The Current Population Survey (CPS) is administered to a scientifically selected multistage probability-based 

sample of households designed to represent the civilian noninstitutional population of each state (and the District 

of Columbia) and the United States as a whole. The sample is made up of addresses, not the names of people or 

families at those addresses. The sample size is determined by specific criteria that ensure the statistical reliability 

of the unemployment rate at the national and state level.

The current sample design was developed after the 2010 decennial census and was implemented beginning in 

2014. This sample will be used until a replacement sample is developed after the next decennial census.

Sample size

The CPS starts with a probability sample of about 74,000 assigned housing units each month. Approximately 

62,000 housing units are eligible for interview each month, after excluding those which are destroyed, vacant, 

converted to nonresidential use, contain only people whose usual place of residence is elsewhere, or are ineligible 

for other reasons. Interviews are completed for about 54,000 housing units. In a given month, about 13 percent of 

housing units are not interviewed, because of the temporary absence of the occupants (they might be on vacation, 

for example), other failures to make contact after repeated attempts, inability of people contacted to respond, 

unavailability for other reasons, and refusals to cooperate. Information is obtained each month on about 105,000 

people ages 16 and older.

In developing the survey sample, a number of criteria are considered, including an acceptable degree of statistical 

reliability for labor force estimates for all states, even those with the smallest populations. The reliability of 

estimates for a wide range of national labor force characteristics also is considered and optimized, within 

budgetary limitations. The reliability criteria of the sample design are explained in the state-based design section of 

Redesign of the sample for the Current Population Survey.

Selection of sample areas

The entire area of the United States is divided into 1,987 Primary Sampling Units (PSUs). Each PSU consists of a 

county or a group of contiguous counties and is defined within state boundaries.

Metropolitan areas within a state are used as a basis for forming many PSUs. Outside of metropolitan areas, two 

or more counties normally are combined to form a PSU, except when the geographic area of an individual county 

is too large. Combining counties to form PSUs provides greater heterogeneity: A typical PSU includes urban and 

rural residents of varying economic levels and encompasses, to the extent feasible, diverse occupations and 

industries. Another important consideration is that the PSU be sufficiently compact so that, with a small sample 

spread throughout it, the PSU can be efficiently canvassed without undue travel costs.
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The 1,987 PSUs are grouped into strata within each state. Then, one PSU is selected from each stratum, with the 

probability of its selection proportional to the population of the PSU. In the first stage of sampling, 852 sample 

areas are chosen from the strata.

Nationally, there are 506 PSUs in strata by themselves. These strata are self-representing and generally are the 

most populous PSUs in each state. The remaining 346 strata are formed by combining PSUs that are similar in 

such characteristics as unemployment, the proportion of housing units with three or more people, the number of 

people employed in various industries, and average monthly wages for various industries. The single PSU 

randomly selected from each of these strata is non-self-representing, because it represents not only itself but the 

entire stratum. The probability of selecting a particular PSU in a non-self-representing stratum is proportional to its 

population in 2010. For example, within a stratum, the chance that a PSU with a population of 50,000 would be 

selected for the sample is twice that for a PSU having a population of 25,000.

Selection of sample households

Because the sample design is state based, the sampling ratio differs by state and depends on the size of the 

state’s population, as well as both national and state reliability requirements. The state sampling ratios range 

roughly from 1 in every 200 households to 1 in every 3,000 households.

The sampling ratio occasionally is modified slightly to hold the size of the sample relatively constant, given the 

overall growth of the population. (The procedure is called “sample maintenance reduction.”) The sampling ratio 

used within a sample PSU depends on the probability of selection of the PSU and the sampling ratio for the state. 

In a sample PSU with a probability of selection of 1 in 10 and a state sampling ratio of 1 in 3,000, a within-PSU 

sampling ratio of 1 in 300 achieves the desired overall ratio of 1 in 3,000 for the stratum. On average, a person in 

the CPS sample represents about 2,500 people in the population.

The current within-PSU sample design was developed with the use of block-level data from the 2010 census. 

Normally, census blocks are bounded by streets and other prominent physical features, such as rivers or railroad 

tracks. County, minor civil division, and census place limits also serve as block boundaries. In cities, blocks can be 

bounded by four streets and be quite small in land area. In rural areas, blocks can be several square miles in size.

Within each block, housing units are sorted geographically and grouped into clusters. A systematic sample of these 

clusters is then independently selected from each stratum by using the appropriate within-PSU sampling ratio. The 

geographic clustering of the sample units reduces travel costs for field representatives.

The vast majority of addresses in the CPS sample are typical housing units, such as single-family homes, 

apartments, and condominiums. However, the CPS sample does include a relatively small number of housing 

arrangements known as “group quarters.” Examples of civilian, noninstitutional group quarters that are within the 

scope of the CPS sample are homeless shelters, group housing for agricultural or mining workers, and convents 

and monasteries. College dormitories also are noninstitutional group quarters, but beginning in late 2017, they 

were excluded from the CPS sample for cost and operational considerations. Most group quarters are of an 
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institutional nature (for example, prisons and nursing homes) or military (for example, barracks) and therefore have 

never been part of the CPS sample.

Rotation of the sample

Part of the sample is changed each month. Each full monthly sample is split into 8 different subsamples called 

rotation groups. Each rotation group is itself a representative sample of the U.S. population. A given rotation group 

is interviewed for a total of 8 months, divided into two equal periods. The group is in the sample for 4 consecutive 

months, leaves the sample during the following 8 months, and then returns for another 4 consecutive months.

Each month, one of the rotation groups is being interviewed for the first time; another is being interviewed for the 

second time; and so on. (The rotation group in the fifth month in the sample is returning after the 8-month break.) 

Under this system, 75 percent of the sample is common from month to month and 50 percent is common from the 

same month a year earlier. This month-to-month and year-to-year overlap in the sample yields better estimates of 

change and improves the reliability of the data without overburdening sampled households.

A full discussion of the sample design process is available in Chapter 3 of Design and methodology: Current

Population Survey, Technical Paper 66. Important updates to the process described in Technical Paper 66 are 

found in Redesign of the Sample for the Current Population Survey (April 2014).

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Calculation

Data processing and preparation

After interviews for the Current Population Survey (CPS) are conducted, the U.S. Census Bureau processes the 

raw data files (as submitted by interviewers) to create a microdata file that can be used to produce estimates. This 

processing includes removing all personally identifiable information, assigning standardized occupation and 

industry classifications, editing the data for completeness and consistency, and creating new data elements based 

on responses to multiple survey questions.

Data from field interviewers and centralized call centers are transmitted to Census Bureau headquarters daily 

during the survey interview period through secure electronic communications. When the Census Bureau’s 

processing activities are completed, the microdata file is securely transferred to the U.S. Bureau of Labor Statistics 

(BLS) for estimation of labor force statistics.

For additional details, including imputation methods, see chapters 8 and 9 of Design and methodology: Current

Population Survey, Technical Paper 66.

Estimation

In order to produce national labor force estimates from the survey microdata, a statistical weight for each person in 

the sample is developed. A series of procedures adjusts the weights for sample records in order to ensure that 

these sample-based estimates of the population match independent population controls for a number of 

geographic and demographic subgroups. On average, a person in the CPS sample represents about 2,500 people 

in the population. The estimation methodology also includes adjustments to account for people who do not 

respond to the survey and to minimize the error range of survey estimates.

The estimation methodology for the CPS is a highly complex set of statistical procedures. A complete discussion of 

the estimation process can be found in chapter 10 of Design and methodology: Current Population Survey,

Technical Paper 66.

Seasonal adjustment

Labor force levels, employment, unemployment, and other labor market measures fluctuate sharply over the 

course of a year because of seasonal events such as weather, major holidays, and the opening and closing of 

schools. Seasonal adjustment is a statistical procedure used to remove seasonal fluctuations from data series, 

thereby making it easier to observe cyclical and other economic trends. A wide range of seasonally adjusted labor 

market measures is available from the CPS. However, not all measures are available on a seasonally adjusted 

basis.

Seasonally adjusted CPS data for the current year are produced with a technique known as concurrent 

adjustment. Under this practice, the current month’s seasonally adjusted estimate is computed with the use of all 

relevant original data up to and including data for the current month. Revisions to estimates for previous months, 
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however, are postponed until the end of the calendar year, at which time BLS re-estimates the seasonal 

adjustment factors for CPS series in order to include the latest 12 months of data in the estimation process. On the 

basis of this annual reestimation, the most recent 5 years of seasonally adjusted CPS data are subject to revision. 

The new seasonal factors and the revised seasonally adjusted series are introduced with the publication of 

December estimates in January of each year. Data series that are not seasonally adjusted, including annual 

averages, are not part of this revision process. Articles describing the annual seasonal adjustment process over 

time are available in the CPS technical documentation.

Population controls

Population controls are independent estimates of the population that are used to weight the CPS sample results so 

that estimates reflect the civilian noninstitutional population ages 16 and older. The Census Bureau develops the 

CPS population controls, which are based on decennial census population counts, supplemented with birth and 

death data and estimates of net international migration.

The Census Bureau reviews and adjusts the population estimates every year. BLS introduces the Census 

Bureau’s annual population control adjustments into CPS estimates for January. The adjustments may increase or 

decrease estimates of the population level, depending on whether the latest information indicates that the 

population estimates have trended high or low. Articles describing the population control adjustments over time are 

available in the CPS technical documentation.

Reliability of the data

Two types of error are possible in an estimate based on a sample survey: sampling error and nonsampling error.

Sampling error. When a sample, rather than an entire population, is surveyed, estimates differ from the true 

population values that they represent. The component of this difference that occurs because samples differ by 

chance is known as sampling error, and its variability is measured by the standard error of the estimate.

A sample estimate and its estimated standard error can be used to construct an approximate confidence interval, 

or range of error. Standard errors and confidence intervals are used to help determine if the difference between 

two estimates is statistically significant or just part of the sampling variability associated with survey estimates.

There is about a 90-percent chance, or level of confidence, that an estimate based on a sample will differ by no 

more than 1.645 standard errors from the true population value because of sampling error. BLS analyses generally 

are conducted at the 90-percent level of confidence.

Estimated standard errors for key CPS data series published by BLS are available in the CPS technical

documentation.

Nonsampling error. Nonsampling error is due to factors that are not related to sample selection. This type of error 

in surveys can be attributed to many sources, including
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the inability to obtain information about all people in the sample

differences in the interpretation of questions

the inability or unwillingness of respondents to provide correct information

the inability to recall information

errors made in collecting and processing the data

errors made in estimating values for missing data

the failure to represent all sample households or all people within sample households (undercoverage).

The full extent of nonsampling error is unknown.

In addition to containing the estimated standard errors for key CPS data series published by BLS, the CPS

technical documentation includes more information about the reliability of CPS estimates, along with guidance on 

calculating approximate standard errors and confidence intervals.

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Presentation

The Current Population Survey (CPS) is the source of the national unemployment rate and provides a wide range 

of information on the social, demographic, and economic characteristics of the civilian noninstitutional population 

ages 16 and older.

Each month, the national unemployment rate and related labor force data are published in The Employment

Situation news release.

At the time of The Employment Situation release, numerous supplemental CPS charts and tables are released 

online and the thousands of CPS labor force series in the BLS public database are updated.

The Employment Situation release dates are available in advance.

From the CPS, the U.S. Bureau of Labor Statistics (BLS) also publishes a quarterly news release on usual weekly

earnings, as well as annual and periodic news releases on a variety of topics, including the following:

Characteristics of union members and union membership rates by sector

Labor force status of veterans by period of military service

Labor force status of people with disabilities

Labor force characteristics of foreign-born workers

School enrollment and work activity among youths

BLS also publishes several annual reports on topics such as minimum-wage workers, the working poor, and 

women’s and men’s earnings.

The Employment Situation and all other current and archived CPS news releases and reports can be accessed 

from the CPS news release page.

For a complete list of CPS topics, with links to available data, see the CPS A to Z index.

A subject index to CPS data in the online public database also is available.

In addition to accessing the regularly tabulated statistics described above, researchers can utilize the public-use 

versions of CPS microdata files to generate customized estimates. These files contain records of the responses to 

the survey questionnaire by all individuals in the survey, with the records edited to protect the confidentiality of the 

respondents. Microdata files are available for all months since January 1976 and for various months in previous 

years.

Starting with the file for January 1994, public-use data files and accompanying documentation can be downloaded 

from the Census Bureau’s Dataweb FTP page. 
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For inquiries regarding data estimation methods and specifications for BLS-published CPS statistics, use the link 

email BLS.

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History

Timeline event 

1940: The Work Projects Administration (WPA) launches the monthly Sample Survey of Unemployment, 

which will later become the Current Population Survey (CPS).

1942: The U.S. Census Bureau assumes responsibility for the monthly unemployment survey, taking over 

from the Work Projects Administration.

1945: The unemployment survey questionnaire is redesigned to improve the identification of people’s 

employment status, especially that of part-time and intermittent workers.

1948: The monthly unemployment survey becomes widely known as the Current Population Survey (CPS).

1953: High-speed electronic equipment is introduced for survey tabulations, greatly increasing the 

timeliness and scope of data available.

1955: The survey reference week of the CPS is changed to the calendar week containing the 12th of the 

month, in order to align it with that of other key labor market surveys. Previously, the calendar week 

containing the 8th was used.

1957: A seasonally adjusted national unemployment rate is introduced.

1959: The CPS becomes a joint endeavor of the U.S. Census Bureau and the U.S. Bureau of Labor 

Statistics (BLS), with the Census Bureau continuing to collect and process the data and BLS assuming 

responsibility for the planning, analysis, and publication of labor force statistics.

1966: The monthly national unemployment rate and other labor market data from the CPS are released 

simultaneously with payroll jobs data from the Current Employment Statistics Survey in The Employment 

Situation. Previously, the unemployment rate and selected labor force data were released about a week 

before the payroll statistics.

1967: The concepts of employment and unemployment, as well as many related concepts, are refined 

following recommendations set forth in 1962 by the President’s Committee to Appraise Employment and 

Unemployment Statistics (“the Gordon Committee”).

1979: The National Commission on Employment and Unemployment Statistics (“the Levitan Commission”) 

issues its final report, which would influence a number of later changes to the survey.

1994: The survey questionnaire undergoes a major redesign to improve and expand labor market 

measures. Many of the refinements adopted are the result of recommendations from the Levitan 

Commission in 1979. The redesign also converts the questionnaire to a fully computer-based survey 

instrument.
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Historical overview

Before the 1930s, there was no monthly survey to count the unemployed. In fact, at that time, there was no 

consensus among economists and statisticians about how the unemployed should be defined and how the 

unemployment rate should be calculated. Mass unemployment during the Great Depression increased the need 

for such statistics, and widely conflicting estimates based on a variety of techniques began to appear.

Dissatisfied with these methods, many research groups, as well as state and municipal governments, began 

experimenting with direct surveys, or samples, of the population. In these surveys, an attempt was made to 

classify the U.S. working-age population into one of three categories: employed, unemployed, or out of the labor 

force. Toward that end, a series of questions was asked about each individual.

By the late 1930s, a set of precise labor force concepts was developed to classify people as working, looking for 

work, or not in the labor force. These concepts were adopted for a national survey of households. Called the 

Monthly Report of Unemployment, the survey was initiated in 1940 by the Work Projects Administration. The 

survey was transferred to the U.S. Census Bureau in 1942 and was later renamed the Current Population Survey 

(CPS). The U.S. Bureau of Labor Statistics (BLS) assumed responsibility for the publication and analysis of the 

monthly CPS labor force data in 1959, while the Census Bureau continued to administer the survey. Since that 

time, the CPS has been a joint endeavor of the two statistical agencies.

Historical comparibility

Over the years, there have been continuous improvements to the survey. The definition of the unemployed, as well 

as the unemployment rate, however, have changed minimally since the concepts were first instituted.

Although the core labor force concepts have held up over time, data users should be aware that there are 

inevitable historical comparability issues and breaks with many CPS series, some more significant than others. 

Historical comparability issues with CPS data typically stem from one or more of the following:

Survey questionnaire changes

There have been relatively few changes to CPS questions over the years. The last major redesign, for example, 

occurred in 1994, when survey questions underwent substantial review and refinement to provide more precise 

and relevant data about a changing labor market. The survey also moved from a paper format to a computerized 

instrument at that time.

For information about changes to survey concepts and questions, see the historical comparability section of the 

CPS technical documentation.

Methodological or estimation procedure changes
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Methodological and related changes do not occur often but are essential to ensuring that survey procedures 

conform to best practices and provide the highest quality data. The CPS has introduced a number of such 

improvements over its history, some of which had more impact on data comparability than others. Some of these 

changes are highly technical in nature, such as those related to sample design and to weighting estimates.

For information about the methodological and related changes, see the historical comparability section of the CPS

technical documentation.

Population control adjustments

Population controls are independent estimates of population that are used to weight the CPS sample results in 

order to reflect the civilian noninstitutional population ages 16 and older. They are adjusted regularly, to reflect the 

latest information about population change. Since 2003, the population controls have been adjusted annually with 

the release of January data.  Prior to 2003, the population controls were adjusted less frequently. 

Some of the population control adjustments have caused significant shifts in estimates of the labor force and 

employment levels that have affected data comparability.

Information about the effects of population control adjustments on major data series is available in the CPS

technical documentation.

Changes in the industry and occupational classification systems

BLS publishes employment and unemployment estimates pertaining to industries and occupations from the CPS. 

The Census Bureau uses standardized classification systems to assign a designated industry and occupation from 

survey responses, but these classification systems are revised periodically to reflect fundamental changes in 

industry structure and types of jobs over time. The revisions create changes in the way industries and occupations 

are grouped and defined—changes that often adversely affect the comparability of historical data. Some of the 

changes in classification represent complete breaks from previous data, affecting their comparability with more 

recent data.

Historical comparability of occupation and industry data from the Current Population Survey describes industry and 

occupational classification changes over time.

Archives

April 17, 2003

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More Information

Visit the U.S. Bureau of Labor Statistics (BLS) Current Population Survey (CPS) homepage for additional 

information. Browse CPS topics, using the A to Z index, with links to data, reports, and more.

Obtain CPS statistics from a number of sources, including the following:

News releases and reports

Monthly, quarterly, and annual tables

The LABSTAT online database, including a subject index to CPS database series, using various tools to

access historical data series

Get contact information for the CPS staff at BLS

See How the Government Measures Unemployment, which contains a nontechnical description of how the 

national unemployment statistics are developed from the CPS.

Get technical documentation about topics such as the following:

Historical comparability of estimates

Industry and occupation classification systems

Population control adjustments

Seasonal adjustment

Reliability of estimates

In addition, see the following Census Bureau technical documentation about data collection and survey design:

The CPS questionnaire

An overview of CPS methodology

Comprehensive documentation about the design and methodology of the CPS

Researchers and others interested in working directly with CPS microdata files can download these files for free, 

along with accompanying documentation, from the Census Bureau’s DataWeb FTP page. In addition to the 

monthly microdata files, data for many CPS supplemental surveys are available.

Last Modified Date: April 10, 2018