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COLLECTION AND COVERAGE

Statistics on the employment status of the population and

related data are compiled by BLS using data from the Current Population Survey (CPS). This monthly survey of households is conducted for BLS by the U.S. Census Bureau

through a scientifically selected sample designed to represent the civilian noninstitutional population. Respondents

are interviewed to obtain information about the employment

status of each member of the household 16 years of age and

older. The inquiry relates to activity or status during the

calendar week, Sunday through Saturday, that includes the

12th day of the month. This is known as the “reference week.”

Actual field interviewing is conducted in the following week,

referred to as the “survey week.”

Each month, about 60,000 occupied units are eligible for

interview. Some 4,500 of these households are contacted but

interviews are not obtained because the occupants are not at

home after repeated calls or are unavailable for other reasons. This represents a noninterview rate for the survey that

ranges between 7 and 8 percent. In addition to the 60,000

occupied units, there are about 12,000 sample units in an

average month that are visited but found to be vacant or

otherwise not eligible for enumeration. Part of the sample is

changed each month. The rotation plan, as will be

explained later, provides for three-fourths of the sample to

be common from one month to the next, and one-half to be

common with the same month a year earlier.

CONCEPTS AND DEFINITIONS

The concepts and definitions underlying labor force data

have been modified, but not substantially altered, since the

inception of the survey in 1940; those in use as of January

1994 are as follows:

Civilian noninstitutional population. Included are persons

16 years of age and older residing in the 50 States and the

District of Columbia who are not inmates of institutions (for

example, penal and mental facilities, homes for the aged),

and who are not on active duty in the Armed Forces.

Employed persons. All persons who, during the reference

week, (a) did any work at all (at least 1 hour) as paid employees, worked in their own business, profession, or on their own

farm, or worked 15 hours or more as unpaid workers in an

enterprise operated by a member of the family, and (b) all those

who were not working but who had jobs or businesses from

which they were temporarily absent because of vacation, illness, bad weather, childcare problems, maternity or paternity

leave, labor-management dispute, job training, or other family or personal reasons, whether or not they were paid for the

time off or were seeking other jobs.

Household Data

(‘‘A” tables, monthly; “D” tables, quarterly)

Each employed person is counted only once, even if he or

she holds more than one job. For purposes of occupation and

industry classification, multiple jobholders are counted in

the job at which they worked the greatest number of hours

during the reference week.

Included in the total are employed citizens of foreign countries who are temporarily in the United States but not living

on the premises of an embassy. Excluded are persons whose

only activity consisted of work around their own house (painting, repairing, or own home housework) or volunteer work

for religious, charitable, and other organizations.

Unemployed persons. 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-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 have

been looking for work to be classified as unemployed.

Duration of unemployment. This represents the length of

time (through the current reference week) that persons classified as unemployed had been looking for work. For persons on layoff, duration of unemployment represents the

number of full weeks they had been on layoff. Mean duration is the arithmetic average computed from single weeks

of unemployment; median duration is the midpoint of a

distribution of weeks of unemployment.

Reason for unemployment. Unemployment also is categorized according to the status of individuals at the time they

began to look for work. The reasons for unemployment are

divided into five major groups: (1) Job losers, comprising

(a) persons on temporary layoff, who have been given a date

to return to work or who expect to return within 6 months

(persons on layoff need not be looking for work to qualify as

unemployed), and (b) permanent job losers, whose employment ended involuntarily and who began looking for work;

(2) Job leavers, persons who quit or otherwise terminated

their employment voluntarily and immediately began looking for work; (3) Persons who completed temporary jobs,

who began looking for work after the jobs ended; (4) Reentrants, persons who previously worked but who were out of

the labor force prior to beginning their job search; and (5)

New entrants, persons who had never worked. Each of these

five categories of the unemployed can be expressed as a

proportion of the entire civilian labor force; the sum of the

four rates thus equals the unemployment rate for all civilian

workers. (For statistical presentation purposes, “job losers”

and “persons who completed temporary jobs” are combined

into a single category until seasonal adjustments can be developed for the separate categories.)
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Jobseekers. All unemployed persons who made specific

efforts to find a job sometime during the 4-week period preceding the survey week are classified as jobseekers. Jobseekers do not include persons classified as on temporary

layoff, who, although often looking for work, are not

required to do so to be classified as unemployed. Jobseekers

are grouped by the methods used to seek work. Only active

methods—which have the potential to result in a job offer

without further action on the part of the jobseeker—qualify

as job search. Examples include going to an employer

directly or to a public or private employment agency, seeking assistance from friends or relatives, placing or answering

ads, or using some other active method. Examples of the

“other” category include being on a union or professional

register, obtaining assistance from a community

organization, or waiting at a designated labor pickup point.

Passive methods, which do not qualify as job search, include

reading (as opposed to answering or placing) “help wanted”

ads and taking a job training course.

Labor force. This group comprises all persons classified as

employed or unemployed in accordance with the criteria

described above.

Unemployment rate. The unemployment rate represents the

number unemployed as a percent of the labor force.

Participation rate. This represents the proportion of the population that is in the labor force.

Employment-population ratio. This represents the proportion of the population that is employed.

Not in the labor force. Included in this group are all persons

in the civilian noninstitutional population who are neither

employed nor 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 discouraged workers, 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), but who are not currently looking because they believe there are no jobs available or there

are none for which they would qualify.

Persons classified as not in the labor force who are in

the sample for either their fourth or eighth month are

asked additional questions relating to job history and

workseeking intentions. These latter data are available on a

quarterly basis.

Occupation, industry, and class of worker. This information

for the employed applies to the job held in the reference

week. Persons with two or more jobs are classified in the job

at which they worked the greatest number of hours. The

unemployed are classified according to their last job.

Beginning in 2003, the occupational and industrial

classification of CPS data is based on the 2002 Census

Bureau occupational and industrial classification systems

which are derived from the 2000 Standard Occupational

Classification (SOC) and the 2002 North American Industry

Classification System (NAICS). (See the following section

on historical comparability for a discussion of previous

classification systems used in the CPS.)

The class-of-worker breakdown 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, profession,

trade, or farm. Only the unincorporated self-employed are

included in the self-employed category in the classof-worker typology. Self-employed persons who respond

that their businesses are incorporated are included among

wage and salary workers because, technically, they are

paid employees of a corporation. Unpaid family workers

are persons working without pay for 15 hours a week

or more on a farm or in a business operated by a member

of the household to whom they are related by birth or

marriage.

Multiple jobholders. These are employed persons who, during the reference week, either had two or more jobs as a wage

and salary worker, were self-employed and also held a wage

and salary job, or worked as an unpaid family worker and

also held a wage and salary job. Excluded are self-employed

persons with multiple businesses and persons with multiple

jobs as unpaid family workers.

Hours of work. These statistics relate to the actual number of

hours worked during the reference week. For example, persons who normally work 40 hours a week but were off on the

Columbus Day holiday would be reported as working 32

hours, even though they were paid for the holiday. For persons working in more than one job, the published figures

relate to the number of hours worked in all jobs during the

week; all the hours are credited to the major job. Unpublished data are available for the hours worked in each job

and for usual hours.

At work part time for economic reasons. Sometimes referred to as involuntary part time, this category 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, inability to

find full-time work, and seasonal declines in demand. Those

who usually work part time must also indicate that they want

and are available for full-time work to be classified as on part

time for economic reasons.

At work part time for noneconomic reasons. This group includes those persons who usually work part time and were at

work 1 to 34 hours during the reference week for a noneconomic reason. Noneconomic reasons include, for example:

Illness or other medical limitations, childcare problems or

other family or personal obligations, school or training, retirement or Social Security limits on earnings, and being in a
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job where full-time work is less than 35 hours. The group

also includes those who gave an economic reason for

usually working 1 to 34 hours but said they do not want

to work full time or are unavailable for such work.

Usual full- or part-time status. Data on persons “at work”

exclude persons who were temporarily absent from a job and

therefore classified in the zero-hours-worked category, “with

a job but not at work.” These are persons who were absent

from their jobs for the entire week for such reasons as bad

weather, vacation, illness, or involvement in a labor dispute.

In order to differentiate a person’s normal schedule from his

or her activity during the reference week, persons also are

classified according to their usual full- or part-time status. In

this context, full-time workers are those who usually worked

35 hours or more (at all jobs combined). This group will

include some individuals who worked less than 35 hours in

the reference week for either economic or noneconomic reasons and those who are temporarily absent from work. Similarly, part-time workers are those who usually work less than

35 hours per week (at all jobs), regardless of the number of

hours worked in the reference week. This may include some

individuals who actually worked more than 34 hours in the

reference week, as well as those who are temporarily absent

from work. The full-time labor force includes all employed

persons who usually work full time and unemployed persons who are either looking for full-time work or are on layoff from full-time jobs. The part-time labor force consists of

employed persons who usually work part time and unemployed persons who are seeking or are on layoff from parttime jobs. Unemployment rates for full- and part-time workers are calculated using the concepts of the full- and parttime labor force.

White, black or African American, and Asian. These are

terms used to describe the race of persons. Persons in these

categories are those who selected that race group only.

Persons in the remaining race categories—American Indian

or Alaska Native, Native Hawaiian or Other Pacific Islanders,

and persons who selected more than one race category—are

included in the estimates of total employment and

unemployment but are not shown separately because the

number of survey respondents is too small to develop

estimates of sufficient quality for monthly publication. In

the enumeration process, race is determined by the

household respondent. (See the following section on

historical comparability for a discussion of changes

beginning in 2003 that affected how people are classified

by race.)

Hispanic or Latino ethnicity. This refers to persons who

identified themselves in the enumeration process as being

Spanish, Hispanic, or Latino. Persons whose ethnicity is

identified as Hispanic or Latino may be of any race. (See

the following section on historical comparability for a

discussion of changes beginning in 2003 that affected how

people are classified by Hispanic or Latino ethnicity.)

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 (for example, annual, monthly, hourly) are converted to weekly. The term “usual” is as perceived by the

respondent. If the respondent asks for a definition of usual,

interviewers are instructed to define the term as more than

half the weeks worked during the past 4 or 5 months. Data

refer to wage and salary workers (excluding all self-employed

persons regardless of whether their businesses were incorporated) who usually work full time on their sole or primary job.

Median earnings. These figures indicate the value that

divides the earnings distribution into two equal parts, one

part having values above the median and the other having

values below the median. The medians shown in this publication are calculated by linear interpolation of the $50 centered interval within which each median falls. Data expressed

in constant dollars are deflated by the Consumer Price

Index for All Urban Consumers (CPI-U).

Never married; married, spouse present; and other marital

status. These are the terms used to define the marital status of

individuals at the time of interview. Married, spouse present,

applies to husband and wife if both were living in the same

household, even though one may be temporarily absent on

business, on vacation, on a visit, in a hospital, etc. Other marital

status applies to persons who are married, spouse absent; widowed; or divorced. Married, spouse absent relates to persons

who are separated due to marital problems, as well as to husbands and wives who are living apart because one or the other

was employed elsewhere or was on duty with the Armed Forces,

or for any other reasons.

Household. A household consists of all persons—related family members and all unrelated persons—who occupy a housing unit and have no other usual address. A house, an apartment, a group of rooms, or a single room is regarded as a

housing unit when occupied or intended for occupancy as

separate living quarters. A householder is the person (or one

of the persons) in whose name the housing unit is owned or

rented. The term is never applied to either husbands or wives

in married-couple families but relates only to persons in

families maintained by either men or women without a spouse.

Family. A family is defined as a group of two or more persons

residing together who are related by birth, marriage, or adoption; all such persons are considered as members of one family. Families are classified either as married-couple families

or as families maintained by women or men without spouses.

A family maintained by a woman or a man is one in which the

householder is either single, widowed, divorced, or married,

spouse absent.

HISTORICAL COMPARABILITY

Changes in concepts and methods

While current survey concepts and methods are very similar
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to those introduced at the inception of the survey in 1940, a

number of changes have been made over the years to

improve the accuracy and usefulness of the data. Some of

the most important changes include:

• In 1945, the questionnaire was radically changed with

the introduction of four basic employment questions. Prior

to that time, the survey did not contain specific question

wording, but, rather, relied on a complicated scheme of

activity prioritization.

• In 1953, the current 4-8-4 rotation system was adopted,

whereby households are interviewed for 4 consecutive

months, leave the sample for 8 months, and then return to the

sample for the same 4 months of the following year. Before

this system was introduced, households were interviewed

for 6 consecutive months and then replaced. The new system

provided some year-to-year overlap in the sample, thereby

improving measurement over time.

• In 1955, the survey reference week was changed to the

calendar week including the 12th day of the month, for greater

consistency with the reference period used for other labor-related statistics. Previously, the calendar week containing the

8th day of the month had been used as the reference week.

• In 1957, the employment definition was modified slightly

as a result of a comprehensive interagency review of labor

force concepts and methods. Two relatively small groups of

persons classified as employed, under “with a job but not at

work,” were assigned to different classifications. Persons on

layoff with definite instructions to return to work within 30

days of the layoff date, and persons volunteering that they

were waiting to start a new wage and salary job within 30 days

of interview, were, for the most part, reassigned to the unemployed classification. The only exception was the small subgroup in school during the reference week but waiting to start

new jobs, which was transferred to not in the labor force.

• In 1967, more substantive changes were made as a result of the recommendations of the President’s Committee

to Appraise Employment and Unemployment Statistics (the

Gordon Committee). The principal improvements were as

follows:

a) A 4-week job search period and specific questions on

jobseeking activity were introduced. Previously, the questionnaire was ambiguous as to the period for jobseeking,

and there were no specific questions concerning job search

methods.

b) An availability test was introduced whereby a person

must be currently available for work in order to be classified

as unemployed. Previously, there was no such requirement.

This revision to the concept mainly affected students, who,

for example, may begin to look for summer jobs in the spring

although they will not be available until June or July. Such

persons, until 1967, had been classified as unemployed but

since have been assigned to the “not in the labor force”

category.

c) Persons “with a job but not at work” because of strikes,

bad weather, etc., who volunteered that they were looking

for work were shifted from unemployed status to employed.

d) The lower age limit for official statistics on employment, unemployment, and other labor force concepts was

raised from 14 to 16 years. Historical data for most major

series have been revised to provide consistent information

based on the new minimum age limit.

e) New questions were added to obtain additional information on persons not in the labor force, including those

referred to as “discouraged workers,” defined as persons who

indicate that they want a job but are not currently looking

because they believe there are no jobs available or none for

which they would qualify.

f) New “probing” questions were added to the questionnaire in order to increase the reliability of information on

hours of work, duration of unemployment, and self-employment.

• In 1994, major changes to the Current Population Survey (CPS) were introduced, which included a complete redesign of the questionnaire and the use of computer-assisted

interviewing for the entire survey. In addition, there were

revisions to some of the labor force concepts and definitions, including the implementation of some changes recommended in 1979 by the National Commission on Employment and Unemployment Statistics (NCEUS, also

known as the Levitan Commission). Some of the major

changes to the survey were:

a) The introduction of a redesigned and automated questionnaire. The CPS questionnaire was totally redesigned in

order to obtain more accurate, comprehensive, and relevant

information, and to take advantage of state-of-the-art computer interviewing techniques.

b) The addition of two, more objective, criteria to the

definition of discouraged workers. Prior to 1994, to be classified as a discouraged worker, a person must have wanted a

job and been reported as not currently looking because of a

belief that no jobs were available or that there were none for

which he or she would qualify. Beginning in 1994, persons

classified as discouraged must also have looked for a job

within the past year (or since their last job, if they worked

during the year), and must have been available for work

during the reference week (a direct question on availability

was added in 1994; prior to 1994, availability had been

inferred from responses to other questions). These changes

were made because the NCEUS and others felt that the previous definition of discouraged workers was too subjective,

relying mainly on an individual’s stated desire for a job and

not on prior testing of the labor market.

c) Similarly, the identification of persons employed part

time for economic reasons (working less than 35 hours in the

reference week because of poor business conditions or because of an inability to find full-time work) was tightened
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by adding two new criteria for persons who usually work

part time: They must want and be available for full-time

work. Previously, such information was inferred. (Persons

who usually work full time but worked part time for an economic reason during the reference week are assumed to meet

these criteria.)

d) Specific questions were added about the expectation of

recall for persons who indicate that they are on layoff. To be

classified as “on temporary layoff,” persons must expect to be

recalled to their jobs. Previously, the questionnaire did not

include explicit questions about the expectation of recall.

e) Persons volunteering that they were waiting to start a

new job within 30 days must have looked for work in the 4

weeks prior to the survey in order to be classified as unemployed. Previously, such persons did not have to meet the

job search requirement in order to be included among the

unemployed.

For additional information on changes in CPS concepts

and methods, see “The Current Population Survey: Design

and Methodology,” Technical Paper 63RV (Washington, U.S.

Census Bureau and Bureau of Labor Statistics, March 2002),

available on the Internet at www.bls.census.gov/cps/tp/

tp63.htm; “Overhauling the Current Population Survey—

Why is it Necessary to Change?,” “Redesigning the Questionnaire,” and “Evaluating Changes in the Estimates,”

Monthly Labor Review, September 1993; and “Revisions in

the Current Population Survey Effective January 1994,” in

the February 1994 issue of this publication.

Noncomparability of labor force levels

In addition to the refinements in concepts, definitions, and

methods made over the years, other changes also have affected the comparability of the labor force data.

• Beginning in 1953, as a result of introducing data from

the 1950 census into the estimating procedures, population levels were raised by about 600,000; labor force,

total employment, and agricultural employment were

increased by about 350,000, primarily affecting the figures for

totals and for men; other categories were relatively

unaffected.

• Beginning in 1960, the inclusion of Alaska and Hawaii

resulted in increases of about 500,000 in the population

and about 300,000 in the labor force. Four-fifths of the

labor force increase was in nonagricultural employment;

other labor force categories were not appreciably affected.

• Beginning in 1962, the introduction of data from the

1960 census reduced the population by about 50,000 and

labor force and employment by about 200,000; unemployment totals were virtually unchanged.

• Beginning in 1972, information from the 1970 census

was introduced into the estimation procedures, increasing

the population by about 800,000; labor force and employment totals were raised by a little more than 300,000;

unemployment levels and rates were essentially unchanged.

• In March 1973, a subsequent population adjustment based

on the 1970 census was introduced. This adjustment, which

affected the white and black-and-other groups but had little

effect on totals, resulted in the reduction of nearly 300,000

in the white population and an increase of the same magnitude

in the black-and-other population. Civilian labor force and

total employment figures were affected to a lesser degree; the

white labor force was reduced by 150,000, and the blackand-other labor force rose by about 210,000. Unemployment

levels and rates were not significantly affected.

• Beginning in January 1974, the method used to prepare independent estimates of the civilian noninstitutional

population was modified to an “inflation-deflation” approach. This change in the derivation of the estimates had

its greatest impact on estimates of 20- to 24-year-old men—

particularly those in the black-and-other population—but

had little effect on estimates of the total population 16 years

and over. Additional information on the adjustment procedure appears in “CPS Population Controls Derived from Inflation-Deflation Method of Estimation,” in the February

1974 issue of this publication.

• Effective in July 1975, as a result of the large inflow of

Vietnamese refugees to the United States, the total and blackand-other independent population controls for persons 16

years and over were adjusted upward by 76,000—30,000

men and 46,000 women. The addition of the refugees increased the black-and-other population by less than 1 percent in any age-sex group, with all of the changes being

confined to the “other” component of the population.

• Beginning in January 1978, the introduction of an

expansion in the sample and revisions in the estimation

procedures resulted in an increase of about 250,000 in the

civilian labor force and employment totals; unemployment

levels and rates were essentially unchanged. An explanation

of the procedural changes and an indication of the differences

appear in “Revisions in the Current Population Survey in

January 1978” in the February 1978 issue of this publication.

• Beginning in October 1978, the race of the individual

was determined by the household respondent for the

incoming rotation group households, rather than by the

interviewer as before. The purpose of this change was to

provide more accurate estimates of characteristics by race.

Thus, in October 1978, one-eighth of the sample households

had race determined by the household respondent and seveneighths of the sample households had race determined by

interviewer observation. It was not until January 1980 that

the entire sample had race determined by the household

respondent. The new procedure had no significant effect on

the estimates.

• Beginning in January 1979, the first-stage ratio adjustment method was changed in the CPS estimation procedure.

Differences between the old and new procedures existed only

for metropolitan and nonmetropolitan area estimates, not

for the total United States. The reasoning behind the change
187

and an indication of the differences appear in “Revisions in

the Current Population Survey in January 1979” in the February 1979 issue of this publication.

• Beginning in January 1982, the second-stage ratio adjustment method was changed. The rationale for the change

and an indication of its effect on national estimates of labor

force characteristics appear in “Revisions in the Current Population Survey Beginning in January 1982” in the February

1982 issue of this publication. In addition, current population estimates used in the second-stage estimation procedure were derived from information obtained from the 1980

census, rather than the 1970 census. This change caused

substantial increases in the total population and in the estimates of persons in all labor force categories. Rates for labor

force characteristics, however, remained virtually unchanged.

Some 30,000 labor force series were adjusted back to 1970

to avoid major breaks in series. The adjustment procedure

used also is described in the February 1982

article cited above. The revisions did not, however, smooth

out the breaks in series occurring between 1972 and 1979

(described above), and data users should consider them when

comparing estimates from different periods.

• Beginning in January 1983, the first-stage ratio adjustment method was updated to incorporate data from the 1980

census. The rationale for the change and an indication of its

effect on national estimates for labor force characteristics

appear in “Revisions in the Current Population Survey

Beginning in January 1983” in the February 1983 issue of

this publication. There were only slight differences between

the old and new procedures in estimates of levels for the

various labor force characteristics and virtually no differences in estimates of participation rates.

• Beginning in January 1985, most of the steps of the

CPS estimation procedure—the noninterview adjustment,

the first- and second-stage ratio adjustments, and the composite estimator—were revised. These procedures are described in the Estimating Methods section. A description of

the changes and an indication of their effect on national

estimates of labor force characteristics appear in “Changes

in the Estimation Procedure in the Current Population Survey Beginning in January 1985” in the February 1985 issue

of this publication. Overall, the revisions had only a slight

effect on most estimates. The greatest impact was on estimates of persons of Hispanic origin. Major estimates were

revised back to January 1980.

• Beginning in January 1986, the population controls used

in the second-stage ratio adjustment method were revised to

reflect an explicit estimate of the number of undocumented

immigrants (largely Hispanic) since 1980 and an improved

estimate of the number of emigrants among legal foreign-born

residents for the same period. As a result, the total civilian

population and labor force estimates were raised by nearly

400,000; civilian employment was increased by about

350,000. The Hispanic-origin population and labor force estimates were raised by about 425,000 and 305,000, respectively,

and Hispanic employment was increased by 270,000. Overall

and subgroup unemployment levels and rates were not significantly affected. Because of the magnitude of the adjustments

for Hispanics, data were revised back to January 1980 to the

extent possible. An explanation of the changes and an indication of their effect on estimates of labor force characteristics

appear in “Changes in the Estimation Procedure in the Current

Population Survey Beginning in January 1986” in the February 1986 issue of this publication.

• Beginning in August 1989, the second-stage ratio estimation procedures were changed slightly to decrease the

chance of very small cells occurring and to be more consistent with published age, sex, race cells. This change had

virtually no effect on national estimates.

• Beginning in January 1994, 1990 census-based population controls, adjusted for the estimated undercount, were

introduced into the second-stage estimation procedure. This

change resulted in substantial increases in total population

and in all major labor force categories. Effective February

1996, these controls were introduced into the estimates for

1990-93. Under the new population controls, the civilian

noninstitutional population for 1990 increased by about 1.1

million, employment by about 880,000, and unemployment

by approximately 175,000. The overall unemployment rate

rose by about 0.1 percentage point. For further information,

see “Revisions in the Current Population Survey Effective

January 1994,” and “Revisions in Household Survey Data

Effective February 1996” in the February 1994 and March

1996 issues, respectively, of this publication.

Additionally, for the period January through May 1994,

the composite estimation procedure was suspended for technical and logistical reasons.

• Beginning in January 1997, the population controls

used in the second-stage ratio adjustment method were revised to reflect updated information on the demographic characteristics of immigrants to, and emigrants from, the United

States. As a result, the civilian noninstitutional population

16 years and over was raised by about 470,000. The labor

force and employment levels were increased by about

320,000 and 290,000, respectively. The Hispanic-origin

population and labor force estimates were raised by about

450,000 and 250,000, respectively, and Hispanic employment was increased by 325,000. Overall and subgroup unemployment rates and other percentages of labor market participation were not affected. An explanation of the changes

and an indication of their effect on national labor force estimates appear in “Revisions in the Current Population Survey Effective January 1997” in the February 1997 issue of

this publication.

• Beginning in January 1998, new composite estimation

procedures and minor revisions in the population controls

were introduced into the household survey. The new composite estimation procedures simplify processing of the

monthly labor force data at BLS, allow users of the survey
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microdata to more easily replicate the official estimates

released by BLS, and increase the reliability of the employment and labor force estimates. The new procedures also produce somewhat lower estimates of the civilian labor force

and employment and slightly higher estimates of unemployment. For example, based on 1997 annual average data, the

differences resulting from the use of old and new composite

weights were as follows: Civilian labor force (-229,000), total

employed (-256,000), and total unemployed (+27,000).

Unemployment rates were not significantly affected.

Also beginning in January 1998, the population controls

used in the survey were revised to reflect new estimates of legal

immigration to the United States and a change in the method

for projecting the emigration of foreign-born legal residents.

As a result, the Hispanic-origin population was raised by about

57,000; however, the total civilian noninstitutional population 16 years and over was essentially unchanged. More detailed information on these changes and their effect on the

estimates of labor force change and composition appear in

“Revisions in the Current Population Survey Effective January 1998,” in the February 1998 issue of this publication.

• Beginning in January 1999, the population controls used

in the survey were revised to reflect newly updated information

on immigration. As a result, the civilian noninstitutional

population 16 years and over was raised by about 310,000.

The impact of the changes varied for different

demographic groups. The civilian noninstitutional population

for men 16 years and over was lowered by about 185,000, while

that for women was increased by about 490,000. The Hispanicorigin population was lowered by about 165,000 while that of

persons of non-Hispanic origin was raised by about 470,000.

Overall labor force and employment levels were increased by

about 60,000 each, while the Hispanic labor force and

employment estimates were reduced by about 225,000 and

215,000, respectively. The changes had only a small impact on

overall and subgroup unemployment rates and other

percentages of labor market participation. An explanation of

the changes and an indication of their effect on national labor

force estimates appear in “Revisions in the Current Population

Survey Effective January 1999” in the February 1999 issue of

this publication.

• Beginning in January 2003, several major changes were

introduced into the CPS. These changes included:

a) Population controls that reflected the results of Census

2000 were introduced into the monthly CPS estimation

process. These new population controls substantially

increased the size of the civilian noninstitutional population

and the civilian labor force. Data from January 2000 through

December 2002 were revised to reflect the higher population

estimates from Census 2000 and the higher rates of

population growth since the census. At the start of the

revision period (January 2000), the new controls raised the

civilian noninstitutional population and the civilian labor

force by 2.6 and 1.6 million, respectively. By December

2002, the civilian population and labor force were 3.8 and

2.5 million, respectively, higher than originally estimated.

In addition to these revisions, the U.S. Census Bureau

introduced another large upward adjustment to the

population controls as part of its annual update of population estimates for 2003. The entire amount of this adjustment was added to the labor force data in January 2003

resulting in increases of 941,000 to the civilian

noninstitutional population and 614,000 to the civilian

labor force. The unemployment rate and other ratios were

not substantially affected by either of these population

control adjustments.

b) The modification of the questions on race and Hispanic

origin to comply with new standards for maintaining,

collecting, and presenting Federal data on race and ethnicity

for Federal statistical agencies. In accordance with the new

standards, the following changes were made to the CPS

questions: 1) Individuals were now asked whether they are

of Hispanic ethnicity before being asked about their race.

Prior to 2003, individuals were asked their ethnic origin

after they were asked about their race. 2) Individuals were

now asked directly if they are Spanish, Hispanic, or Latino.

Previously, individuals were identified as Hispanic based

on their, or their ancestors’, country of origin. 3) With respect

to race, the response category of Asian and Pacific Islanders

was split into two categories: a) Asian and b) Native Hawaiian

or Other Pacific Islanders. 4) Individuals were allowed to

choose more than one race category. Prior to 2003,

individuals who considered themselves to belong to more

than one race were required to select a single primary race.

5) The questions were reworded to indicate that individuals

could select more than one race category and to convey

more clearly that individuals should report their own

perception of what their race is. These changes had no impact

on the overall civilian noninstitutional population and

civilian labor force but did reduce the population and labor

force levels of whites, blacks or African Americans, and

Asians beginning in January 2003. For whites and blacks,

the differences resulted from the exclusion of individuals

who reported more than one race from those groups. For

Asians, the difference resulted from the same restriction as

well as the split of the old Asian and Pacific Islander category

into two separate categories. Analysis of data from a special

CPS supplement conducted in May 2002 indicated that these

changes reduced the population and labor force levels for

whites by about 950,000 and 730,000, respectively, and for

blacks and African Americans by about 320,000 and 240,000,

respectively, while having little or no impact on their

unemployment rates. For Asians, the changes had the effect

of reducing the their population by about 1.1 million and

their labor force by about 720,000, but did not have a

statistically significant effect on their unemployment rate.

The changes did not affect the size of the Hispanic or Latino

population and had no significant impact on the size of

their labor force, but did cause an increase of about half a

percentage point in their unemployment rate.
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c) Improvements were introduced to both the secondstage and composite weighting procedures. These changes

adapted the weighting procedures to the new race/ethnic

classification system and enhanced the stability over time

of national and State/substate labor force estimates for

demographic groups.

More detailed information on these changes and an

indication of their effect on national labor force estimates

appear in “Revisions to the Current Population Survey

Effective in January 2003” in the February 2003 issue of

this publication available on the Internet at http://

www.bls.gov/cps/rvcps03.pdf.

• Beginning in January 2004, the population controls

used in the survey were updated to reflect revised estimates

of net international migration for 2000 through 2003. The

updated controls resulted in a decrease of 560,000 in the

estimated size of the civilian noninstitutional population

16 years of age and over for December 2003. The civilian

labor force and employment levels decreased by 437,000

and 409,000, respectively. The Hispanic or Latino population and labor force estimates declined by 583,000 and

446,000, respectively and Hispanic or Latino employment

was lowered by 421,000. The updated controls had little or

no effect on overall and subgroup unemployment rates and

measures of labor market participation. More detailed

information on the effect of the updated controls on

national labor force estimates appears in “Adjustments to

Household Survey Population Estimates in January 2004”

in the February 2004 issue of this publication available on

the Internet at http://www.bls.gov/cps/cps04adj.pdf.

• Beginning in January 2005, the population controls used

in the survey were adjusted to reflect revised estimates of

net international migration and updated vital statistics

information. The updated controls resulted in a decrease of

8,000 in the estimated size of the civilian noninstitutional

population 16 years of age and over for December 2004. The

civilian labor force and employment levels decreased by

49,000 and 45,000, respectively. The updated controls had

no effect on overall and subgroup unemployment rates and

measures of labor market participation such as the labor force

participation rate and the employment-population ratio. More

detailed information on the effect of the updated controls on

national labor estimates appears in “Adjustments to

Household Survey Population Estimates in January 2005” in

the February 2005 issue of this publication available on the

Internet at http://www.bls.gov/cps/cps05adj.pdf.

• Beginning in January 2006, the population controls used

in the survey were adjusted to reflect revised estimates of

net international migration and updated vital statistics

information. The updated controls resulted in a decrease of

67,000 in the estimated size of the civilian noninstitutional

population 16 years of age and over for December 2005. The

civilian labor force and employment levels decreased by

130,000 and 123,000, respectively. The updated controls had

no effect on overall and subgroup unemployment rates and

measures of labor market participation such as the labor force

participation rate and the employment-population ratio. More

detailed information on the effect of the updated controls on

national labor estimates appears in “Adjustments to

Household Survey Population Estimates in January 2006” in

the February 2006 issue of this publication available on the

Internet at http://www.bls.gov/cps/cps06adj.pdf.

Changes in the occupational and industrial

classification systems

Beginning in 1971, the comparability of occupational

employment data was affected as a result of changes in the

occupational classification system for the 1970 census that

were introduced into the CPS. Comparability was further

affected in December 1971, when a question relating to

major activity or duties was added to the monthly CPS questionnaire in order to more precisely determine the occupational

classification of individuals. As a result of these changes, meaningful comparisons of occupational employment levels could

not be made between 1971-72 and prior years nor between

those 2 years. Unemployment rates were not significantly

affected. For a further explanation of the changes in the occupational classification system, see“Revisions in Occupational

Classifications for 1971” and “Revisions in the Current Population Survey” in the February 1971 and February 1972 issues,

respectively, of this publication.

Beginning in January 1983, the occupational and industrial

classification systems used in the 1980 census were introduced

into the CPS. The 1980 census occupational classification

system evolved from the Standard Occupational Classification

(SOC) system and was so radically different in concepts and

nomenclature from the 1970 system that comparisons of

historical data are not possible without major adjustments. For

example, the 1980 major group “sales occupations” is

substantially larger than the 1970 category “sales workers.”

Major additions include “cashiers” from “clerical workers” and

some self-employed proprietors in retail trade establishments

from “managers and administrators, except farm.”

The industrial classification system used in the 1980 census was based on the 1972 Standard Industrial Classification

(SIC) system, as modified in 1977. The adoption of the new

system had much less of an adverse effect on historical comparability than did the new occupational system. The most

notable changes from the 1970 system were the transfer of

farm equipment stores from “retail” to “wholesale” trade and

of postal service from “public administration” to “transportation,” and some interchange between “professional and

related services” and “public administration.” Additional information on the 1980 census occupational and industrial

classification systems appears in “Revisions in the Current

Population Survey Beginning in January 1983” in the February 1983 issue of this publication.

Beginning in January 1992, the occupational and industrial classification systems used in the 1990 census were introduced into the CPS. (These systems were based largely on the
190

1980 Standard Occupational Classification (SOC) and 1987

Standard Industrial Classification (SIC) systems, respectively.)

There were a few breaks in comparability between the 1980

and 1990 census-based systems, particularly within the “technical, sales, and administrative support” categories. The most

notable changes in industry classification were the shift of

several industries from “business services” to “professional

services” and the splitting of some industries into smaller, more

detailed categories. A number of industry titles were changed

as well, with no change in content.

Beginning in January 2003, the 2002 Census Bureau

occupational and industrial classification systems were

introduced into the CPS. These systems were derived from

the 2000 Standard Occupational Classification (SOC) and

the 2002 North American Industry Classification System

(NAICS). The composition of detailed occupational and industrial classifications in the new classification systems was

substantially changed from the previous systems in use as

was the structure for aggregating them into broad groups.

Consequently, the use of the new classification systems

created breaks in existing data series at all levels of

aggregation. Additional information on the 2002 Census

Bureau occupational and industrial classification systems

appears in “Revisions to the Current Population Survey

Effective in January 2003” in the February 2003 issue

of this publication available on the Internet at http://

www.bls.gov/cps/rvcps03.pdf.

Sampling

Since the inception of the survey, there have been various

changes in the design of the CPS sample. The sample traditionally is redesigned and a new sample selected after each

decennial census. Also, the number of sample areas and the

number of sample persons are changed occasionally. Most

of these changes are made to improve the efficiency of the

sample design, increase the reliability of the sample estimates, or control cost.

Changes in this regard since 1960 are as follows: When

Alaska and Hawaii received statehood in 1959 and 1960,

respectively, three sample areas were added to the existing

sample to account for the population of these States. In January 1978, a supplemental sample of 9,000 housing units,

selected in 24 States and the District of Columbia, was designed to provide more reliable annual average estimates for

States. In October 1978, a coverage improvement sample of

approximately 450 sample household units representing

237,000 occupied mobile homes and 600,000 new construction housing units was added. In January 1980, another

supplemental sample of 9,000 households selected in 32

States and the District of Columbia was added. A sample

reduction of about 6,000 units was implemented in May 1981.

In January 1982, the sample was expanded by 100 households to provide additional coverage in counties added to

the Standard Metropolitan Statistical Areas (SMSAs), which

were redefined in 1973. In January 1985, a new State-based

CPS sample was selected based on 1980 census

information. A sample reduction of about 4,000 households

was implemented in April 1988; the households were reinstated during the 8-month period, April-November 1989. A

redesigned CPS sample based on the 1990 decennial census

was selected for use during the 1990s. Households from this

new sample were phased into the CPS between April 1994

and July 1995. The July 1995 sample was the first monthly

sample based entirely on the 1990 census. For further information on the 1990 sample redesign, see “Redesign of the

Sample for the Current Population Survey” in the May 1994

issue of this publication.

In 1996, the original sample design reliability criteria

were modified to reduce costs. In July 2001, the CPS sample

was expanded to support the State Children’s Health Insurance Program. A redesigned CPS sample based on Census

2000, the 2000 decennial census, was selected for use during the 2000s. Households from the new sample were phased

into the CPS from April 2004 to July 2005. The July 2005

sample was the first monthly sample based entirely on Census 2000. For further information on the 2000 sample redesign, see “Redesign of the Sample for the Current Population Survey” in the December 2004 issue of this publication.

The current criteria, given below, are based on the coefficient of variation (CV) of the unemployment level, where

the CV is defined as the standard error of the estimate divided by the estimate, expressed as a percentage. These CV

controls assume a 6-percent unemployment rate to establish

a consistent specification of sampling error.

The current sample design includes about 72,000 “assigned” housing units from 824 sample areas. Sufficient

sample is allocated to maintain, at most, a 1.9-percent CV

on national monthly estimates of unemployment level, assuming a 6-percent unemployment rate. This translates into

a change of 0.2 percentage point in the unemployment rate

being significant at a 90-percent confidence level. For each

of the 50 States and for the District of Columbia, the design

maintains a CV of at most 8 percent on the annual average

estimate of unemployment level, assuming a 6-percent unemployment rate. About 60,000 housing units are required

in order to meet the national and State reliability criteria.

Due to the national reliability criterion, estimates for several large States are substantially more reliable than the

State design criterion requires. Annual average unemployment estimates for California, Florida, New York, and Texas,

for example, carry a CV of less than 4 percent. In support of

the State Children’s Health Insurance Program, about 12,000

additional housing units are allocated to the District of Columbia and 26 States. (These are generally the States with

the smallest samples after the 60,000 housing units are allocated to satisfy the national and State reliability criteria.)

In the first stage of sampling, the 824 sample areas are

chosen. In the second stage, ultimate sampling units are

selected. Each month, about 72,000 housing units are assigned for data collection, of which about 60,000 are occupied and thus eligible for interview. The remainder are units
191

found to be destroyed, vacant, converted to nonresidential

use, containing persons whose usual place of residence is

elsewhere, or ineligible for other reasons. Of the 60,000

housing units, about 7.5 percent are not interviewed in a

given month due to temporary absence (vacation, etc.), other

failures to make contact after repeated attempts, inability of

persons contacted to respond, unavailability for other reasons, and refusals to cooperate (about half of the

noninterviews). Information is obtained each month for about

112,000 persons 16 years of age or older.

Selection of sample areas. The entire area of the United

States, consisting of 3,142 counties and independent cities,

is divided into 2,025 sample units (PSUs). A PSU consists of

a county or a number of contiguous counties.

Metropolitan areas within a State are used as a basis for

forming PSUs. Outside of metropolitan areas, counties normally are combined 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 both high and low 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 can be efficiently canvassed

without undue travel cost.

The 2,025 PSUs are grouped into strata within each State.

Then, one PSU is selected from each stratum with the probability of selection proportional to the population of the

PSU. Nationally, there are a total of 446 PSUs in strata by

themselves. These strata are self-representing and are generally the most populous PSUs in each State. The 328 remaining strata are formed by combining PSUs that are similar in

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

employed in various industries, and average monthly wages

for various industries. The single PSU randomly selected

from each of these strata is nonself-representing because it

represents not only itself but the entire stratum. The probability of selecting a particular PSU in a nonself-representing stratum is proportional to its 2000 population. 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

State population size as well as both national and State reliability requirements. The State sampling ratios range roughly

from 1 in every 100 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 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

3,000, a within-PSU sampling ratio of 1 in 300 achieves the

desired ratio of 1 in 3,000 for the stratum.

The 2000 within-PSU sample design was developed using

block-level data from Census 2000. 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.

For the purpose of sample selection, census blocks were

grouped into three strata: Unit, group quarters, and area.

(Occasionally, units within a block were split between the

unit and group-quarters strata.) The unit stratum contained

regular housing units with addresses that were easy to locate

(for example, most single-family homes, townhouses, condominiums, apartment units, and mobile homes). The groupquarters stratum contained housing units in which residents

shared common facilities or received formal or authorized

care or custody. Unit and group-quarters blocks exist primarily in urban areas. The area stratum contains blocks with

addresses that are more difficult to locate. Area blocks exist

primarily in rural areas.

To reduce the variability of the survey estimates and to ensure that the within-PSU sample would reflect the demographic

and socioeconomic characteristics of the PSU, blocks within

the unit, group-quarters, and area strata were sorted using geographic and block-level data from the census. Examples of the

census variables used for sorting include proportion of minority renter-occupied housing units, proportion of housing units

with female householders, and proportion of owner-occupied

housing units. The specific sorting variables used differed by

type of PSU (urban or rural) and stratum.

Within each block, housing units were sorted geographically. A systematic sample of these units was then selected

independently from each stratum using the appropriate withinPSU sampling ratio. The geographic sorting of the sample units

reduces field representative travel costs. Prior to interviewing,

special listing procedures are used to locate the particular

sample addresses in the group-quarters and area blocks.

Units in the three strata described above all existed at the

time of Census 2000. Through a series of additional procedures, a sample of building permits is included in the CPS to

represent housing units built after the decennial census.

Adding these newly built units keeps the sample up to date

and representative of the population. It also helps to keep

the sample size stable: Over the life of the sample, the addition of newly built housing units compensates for the loss of

“old” units that may be abandoned, demolished, or converted to nonresidential use.

Rotation of sample. Part of the sample is changed each

month. Each monthly sample is divided into eight representative subsamples or rotation groups. A given rotation group

is interviewed for a total of 8 months, divided into two equal

periods. It is in the sample for 4 consecutive months, leaves

the sample during the following 8 months, and then returns
192

for another 4 consecutive months. In each monthly sample,

one of the eight rotation groups is in the first month of enumeration, another rotation group is in the second month, and

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

year to year for the same month. This procedure provides a

substantial amount of month-to-month and year-to-year overlap in the sample, thus providing better estimates of change

and reducing discontinuities in the data series without burdening any specific group of households with an unduly

long period of inquiry.

CPS sample, 1947 to present. Table 1-A provides a

description of some aspects of the CPS sample designs in use

since 1947. A more detailed account of the history of the

CPS sample design appears in chapter 2 of “The Current

Population Survey: Design and Methodology,” Technical

Paper 63RV, (Washington, U.S. Census Bureau and Bureau

of Labor Statistics, March 2002), available on the Internet at

www.bls.census.gov/cps/tp/tp63.htm. A description of the

Census 2000-based sample design appears in “Redesign of

the Sample for the Current Population Survey,” in the

December 2004 issue of this publication.

ESTIMATING METHODS

Under the estimating methods used in the CPS, all of the

results for a given month become available simultaneously

and are based on returns from the entire panel of respondents. The estimation procedure involves weighting the data

from each sample person by the inverse of the probability of

the person being in the sample. This gives a rough measure

of the number of actual persons that the sample person represents. Since 1985, most sample persons within the same State

have had the same probability of selection. Some selection

probabilities may differ within a State due to the sample

design or for operational reasons. Field subsampling, for example, which is carried out when areas selected for the sample

are found to contain many more households than expected,

may cause probabilities of selection to differ for some sample

areas within a State. Through a series of estimation steps

(outlined below), the selection probabilities are adjusted for

noninterviews and survey undercoverage; data from previous months are incorporated into the estimates through the

composite estimation procedure.

1. Noninterview adjustment. The weights for all interviewed

households are adjusted to account for occupied sample

households for which no information was obtained because

of absence, impassable roads, refusals, or unavailability of

the respondents for other reasons. This noninterview adjustment is made separately for clusters of similar sample areas

that are usually, but not necessarily, contained within a State.

Similarity of sample areas is based on Metropolitan Statistical Area (MSA) status and size. Within each cluster, there is

a further breakdown by residence. Each MSA cluster is split

by “central city” and “balance of the MSA.” Each non-MSA

cluster is split by “urban” and “rural” residence categories.

The proportion of sample households not interviewed varies

from 7 to 8 percent, depending on weather, vacation, etc.

2. Ratio estimates. The distribution of the population selected for the sample may differ somewhat, by chance, from

that of the population as a whole in such characteristics as

age, race, sex, and State of residence. Because these characteristics are closely correlated with labor force participation

Table 1-A. Characteristics of the CPS sample, 1947 to present

Aug. 1947 to Jan. 1954 ............................... 68 21,000 500-1,000 3,000-3,500

Feb. 1954 to Apr. 1956 ............................... 230 21,000 500-1,000 3,000-3,500

May 1956 to Dec.1959 ............................... 1330 33,500 1,500 6,000

Jan. 1960 to Feb. 1963 ............................... 2333 33,500 1,500 6,000

Mar. 1963 to Dec.1966 ............................... 357 33,500 1,500 6,000

Jan. 1967 to July 1971 ............................... 449 48,000 2,000 8,500

Aug. 1971 to July 1972 ............................... 449 45,000 2,000 8,000

Aug. 1972 to Dec.1977 ............................... 461 45,000 2,000 8,000

Jan. 1978 to Dec.1979 ............................... 614 53,500 2,500 10,000

Jan. 1980 to Apr. 1981 ............................... 629 62,200 2,800 12,000

May 1981 to Dec.1984 ............................... 629 57,800 2,500 11,000

Jan. 1985 to Mar. 1988 ............................... 729 57,000 2,500 11,000

Apr. 1988 to Mar. 1989 ............................... 729 53,200 2,600 11,500

Apr. 1989 to Oct. 1994 3 .............................. 729 57,400 2,600 11,800

Nov. 1994 to Aug. 1995 4 ............................ 792 54,500 3,500 10,000

Sept. 1995 to Dec. 1995 ................................ 792 52,900 3,400 9,700

Jan. 1996 to June 2001.................................. 754 46,250 3,750 10,000

July 2001 to July 2004 5 ................................ 754 55,500 4,500 12,000

Aug. 2004 to present 5 .................................... 824 55,500 4,500 12,000

Interviewed Not interviewed

Households eligible Households visited

but not eligible

Number of sample

areas Period

1 Beginning in May 1956, these areas were chosen to provide coverage in

each State and the District of Columbia.

2 Three sample areas were added in 1960 to represent Alaska and Hawaii

after statehood.

3 The sample was increased incrementally during the 8-month period, AprilNovember 1989.

4 Includes 2,000 additional assigned housing units from Georgia and Virginia

that were gradually phased in during the 10-month period, October 1994-

August 1995.

5 Includes 12,000 assigned housing units in support of the State Children’s

Health Insurance Program.
193

and other principal measurements made from the sample, the

survey estimates can be substantially improved when

weighted appropriately by the known distribution of these

population characteristics. This is accomplished through

two stages of ratio adjustment, as follows:

a. First-stage ratio estimation. The purpose of the firststage ratio adjustment is to reduce the contribution to variance that results from selecting a sample of PSUs rather than

drawing sample households from every PSU in the Nation.

This adjustment is made to the CPS weights in two race cells:

Black and nonblack; it is applied only to PSUs that are not

self-representing and for those States that have a substantial

number of black households. The procedure corrects for differences that existed in each State cell at the time of Census

2000 between 1) the race distribution of the population in

sample PSUs and 2) the race distribution of all PSUs. (Both 1

and 2 exclude self-representing PSUs.)

b. National coverage adjustment. The purpose of this

step is to improve the adjustment for subpopulations most

prone to undercoverage. It adjusts CPS sample weights to

independent population estimates for 34 white nonHispanic, 26 black non-Hispanic, 18 Asian non-Hispanic,

18 residual race non-Hispanic, 26 white Hispanic, and 4

non-white Hispanic age-sex cells.

c. State coverage adjustment. This step adjusts CPS

sample weights to independent state population estimates.

The number of age-sex cells for each state varies, depending

on the black and nonblack population.

d. Second-stage ratio estimation. This procedure substantially reduces the variability of estimates and corrects,

to some extent, for CPS undercoverage. A national-coverage

step and a State-coverage step make preliminary corrections

for undercoverage. The CPS sample weights are then adjusted to ensure that sample-based estimates of population

match independent population controls. Three sets of controls are used in different steps of the procedure:

1) State step: Civilian noninstitutional population

controls for 6 age-sex cells in the Los Angeles-Long Beach

metropolitan area, the balance of California, New York City,

the balance of New York State, each of the other 48 States,

and the District of Columbia.

2) Ethnicity step: National civilian noninstitutional

population controls for 26 Hispanic and 26 non-Hispanic

age-sex cells.

3) Race step: National civilian noninstitutional

population controls for 34 white, 26 black, and 26 Asianplus-residual-race age-sex cells.

The independent population controls are prepared by projecting forward the resident population as enumerated on

April 1, 2000. The projections are derived by updating

demographic census data with information from a variety of

other data sources that account for births, deaths, and net

migration. Estimated numbers of resident Armed Forces

personnel and institutionalized persons reduce the resident

population to the civilian noninstitutional population. Prior

to January 2003, the projections were based on earlier

censuses. See “Revisions to the Current Population Survey

Effective in January 2003,” in the February 2003 issue of

this publication for a detailed discussion of changes to the

second-stage weighting and composite estimating procedures that were introduced in January 2003.

3. Composite estimation procedure. The last step in the

preparation of most CPS estimates makes use of a composite

estimation procedure. The composite estimate consists of a

weighted average of two factors: The two-stage ratio estimate based on the entire sample from the current month and

the composite estimate for the previous month, plus an estimate of the month-to-month change based on the six rotation groups common to both months. In addition, a bias

adjustment term is added to the weighted average to

account for relative bias associated with month-in-sample

estimates. This month-in-sample bias is exhibited by

unemployment estimates for persons in their first and fifth

months in the CPS being generally higher than estimates

obtained for the other months.

The composite estimate results in a reduction in the sampling error beyond that which is achieved after the two stages

of ratio adjustment. For some items, the reduction is substantial. The resultant gains in reliability are greatest in estimates

of month-to-month change, although gains usually are also

obtained for estimates of level in a given month, change from

year to year, and change over other intervals of time.

Rounding of estimates

The sums of individual items may not always equal the totals shown in the same tables because of independent rounding of totals and components to the nearest thousand. Similarly, sums of percent distributions may not always equal

100 percent because of rounding. Differences, however, are

insignificant.

Reliability of the estimates

An estimate based on a sample survey has two types of error

sampling error and nonsampling error. The estimated standard

errors provided in this publication are approximations of the

true sampling errors. They incorporate the effect of some

nonsampling errors in response and enumeration, but do not

account for any systematic biases in the data.

Nonsampling error. The full extent of nonsampling error is

unknown, but special studies have been conducted to quantify some sources of nonsampling error in the CPS. The

effect of nonsampling error is small on estimates of relative

change, such as month-to-month change; estimates of

monthly levels tend to be affected to a greater degree.

Nonsampling errors in surveys can be attributed to many

sources, for example, the inability to obtain information about

all persons in the sample; differences in the interpretation of

questions; inability or unwillingness of respondents to pro-
194

vide correct information; inability of respondents to recall

information; errors made in collecting and processing the

data; errors made in estimating values for missing data; and

failure to represent all sample households and all persons

within sample households (undercoverage).

Nonsampling errors occurring in the interview phase of

the survey are studied by means of a reinterview program.

This program is used to estimate various sources of error, as

well as to evaluate and control the work of the interviewers.

A random sample of each interviewer’s work is inspected

through reinterview at regular intervals. The results

indicate, among other things, that the data published

from the CPS are subject to moderate systematic biases.

A description of the CPS reinterview program may be

found in Appendix G, “Reinterview: Design and Methodology,” of “The Current Population Survey: Design and

Methodology,” Technical Paper 63RV (Washington,

U.S. Census Bureau and Bureau of Labor Statistics, March

2002), available on the Internet at www.bls.census.gov/cps/

tp/tp63.htm.

The effects of some components of nonsampling error in

the CPS data can be examined as a result of the rotation plan

used for the sample, because the level of the estimates varies

by rotation group. A description appears in Barbara A. Bailar,

“The Effects of Rotation Group Bias on Estimates from Panel

Surveys,” Journal of the American Statistical Association,

March 1975, pp. 23-30.

Undercoverage in the CPS results from missed housing

units and missed persons within sample households. The

CPS covers about 92 percent of the decennial census population (adjusted for census undercount). It is known that the

CPS undercoverage varies with age, sex, race, and Hispanic

origin. Generally, undercoverage is larger for men than for

women and is larger for blacks, Hispanics, and other races

than for whites. Ratio adjustment to independent age-sexrace-origin population controls, as described previously,

partially corrects for the biases due to survey undercoverage.

However, biases exist in the estimates to the extent that missed

persons in missed households or missed persons in interviewed households have characteristics different from

those of interviewed persons in the same age-sex-race-origin

group.

Additional information on nonsampling error in the CPS

appears in Camilla Brooks and Barbara Bailar, “An Error

Profile: Employment as Measured by the Current Population

Survey,” Statistical Policy Working Paper 3 (Washington,

U.S. Department of Commerce, Office of Federal Statistical

Policy and Standards, September 1978); Marvin Thompson

and Gary Shapiro, “The Current Population Survey: An

Overview,” Annals of Economic and Social Measurement,

Vol. 2, April 1973; and “The Current Population Survey:

Design and Methodology,” Technical Paper 63RV referenced

above. The last document includes a comprehensive

discussion of various sources of errors and describes attempts

to measure them in the CPS.

Sampling error. When a sample, rather than the entire population, is surveyed, estimates differ from the true population values that they represent. This difference, or sampling error, occurs by chance, and its variability is measured by the standard

error of the estimate. Sample estimates from a given survey

design are unbiased when an average of the estimates from all

possible samples would yield, hypothetically, the true population value. In this case, the sample estimate and its standard

error can be used to construct approximate confidence intervals, or ranges of values that include the true population value

with known probabilities. If the process of selecting a sample

from the population were repeated many times, an estimate

made from each sample, and a suitable estimate of its standard

error calculated for each sample, then:

1. Approximately 68 percent of the intervals from one

standard error below the estimate to one standard error above

the estimate would include the true population value.

2. Approximately 90 percent of the intervals from 1.645

standard errors below the estimate to 1.645 standard errors

above the estimate would include the true population value.

3. Approximately 95 percent of the intervals from 1.96

standard errors below the estimate to 1.96 standard errors

above the estimate would include the true population value.

These confidence interval statements are approximately

true for the CPS. Although the estimating methods used in

the CPS do not produce unbiased estimates, biases for most

estimates are believed to be small. Methods for estimating

standard errors reflect not only sampling errors but also some

kinds of nonsampling error. Although both the estimates

and the estimated standard errors depart from the theoretical

ideal, the departures are minor and have little impact

on the confidence interval statements. When clarity is

needed, an estimated confidence interval is specified to be

“approximate,” as is the estimated standard error used in the

computation.

Tables 1-B through 1-D are provided so that approximate

standard errors of estimates can be easily obtained. Tables

1-B and 1-C give approximate standard errors for estimated

monthly levels and rates for selected employment status

characteristics; the tables also provide approximate

standarderrors for consecutive month-to-month changes in

the estimates. It is impractical to show approximate standard

errors for all CPS estimates in this publication, so table 1-D

provides parameters and factors that allow the user to

calculate approximate standard errors for a wide range of

estimated levels, rates, and percentages, and also changes

over time. The parameters and factors are used in formulas

that are commonly called generalized variance functions.

The approximate standard errors provided in this publication are based on the sample design and estimation procedures as of 1996, and reflect the population levels and sample

size as of that year. Standard errors for years prior to 1996

may be roughly approximated by applying these adjustments

to the standard errors presented here. (More accurate stan-
195

 

 

Total

Total, 16 years and over:

Civilian labor force .................... 300 246

Employed .................................. 323 265

Unemployed ............................. 155 172

Men, 20 years and over:

Civilian labor force .................... 162 133

Employed .................................. 185 152

Unemployed ............................. 104 115

Women, 20 years and over:

Civilian labor force .................... 207 170

Employed .................................. 217 178

Unemployed ............................. 92 102

 Both sexes, 16 to 19 years:

Civilian labor force .................... 145 142

Employed .................................. 132 130

Unemployed ............................. 61 75

Black or African American

Total, 16 years and over:

Civilian labor force .................... 125 102

Employed .................................. 134 110

Unemployed ............................. 74 82

Men, 20 years and over:

Civilian labor force .................... 76 63

Employed .................................. 83 68

Unemployed ............................. 48 53

Women, 20 years and over:

Civilian labor force .................... 79 65

Employed .................................. 85 70

Unemployed ............................. 46 52

Both sexes, 16 to 19 years:

Civilian labor force .................... 41 40

Employed .................................. 37 36

Unemployed ............................. 27 34

Asian

Total, 16 years and over:

Civilian labor force .................... 80 66

Employed .................................. 82 67

Unemployed ............................. 29 33

Hispanic or Latino ethnicity

 Total, 16 years and over:

Civilian labor force .................... 119 97

Employed .................................. 129 105

Unemployed ............................. 66 73

Characteristic

Table 1-B. Approximate standard errors for major employment status categories

(In thousands)

Monthly

level

Consecutive

month-tomonth change

dard error estimates for historical CPS data may be found in

previous issues of this publication.)

1. For the years 1967 through 1995, multiply the standard errors by 0.96.

2. For the years 1956 through 1966, multiply the standard errors by 1.17.

3. For years prior to 1956, multiply the standard errors by

1.44.

Use of tables 1-B and 1-C. These tables provide a quick

reference for standard errors of major characteristics. Table

1-B gives approximate standard errors for estimates of

monthly levels and consecutive month-to-month changes

in levels for major employment status categories. Table 1-C

gives approximate standard errors for estimates of monthly

unemployment rates and consecutive month-to-month

changes in unemployment rates for some demographic,

occupational, and industrial categories. For characteristics

not given in tables 1-B and 1-C, refer to table 1-D.

Illustration. Suppose that, for a given month, the number

of women age 20 years and over in the civilian labor force is

estimated to be 65,000,000. For this characteristic, the approximate standard error of 207,000 is given in table

1-B in the row “Women, 20 years and over; Civilian labor

force.” To calculate an approximate 90-percent confidence

interval, multiply the standard error of 207,000 by the factor 1.645 to obtain 341,000. This number is subtracted

from and then added to 65,000,000 to obtain an approximate 90-percent confidence interval: 64,659,000 to

65,341,000. Concluding that the true civilian labor force

level lies within an interval calculated in this way would be

correct for roughly 90 percent of all possible samples that

could have been selected for the CPS.

Use of table 1-D. This table gives a and b parameters that can

be used with formulas to calculate approximate monthly standard errors for a wide range of estimated levels, proportions,

and rates. Factors are provided to convert monthly measures

into approximate standard errors of estimates for other periods

(quarterly and yearly averages) and approximate standard errors for changes over time (consecutive monthly changes,

changes in consecutive quarterly and yearly averages, and

changes in monthly estimates 1 year apart).

The standard errors for estimated changes in level from

one month to the next, one year to the next, etc., depend

more on the monthly levels for characteristics than on the

size of the changes. Likewise, the standard errors for changes

in rates (or percentages) depend more on the monthly rates

(or percentages) than on the size of the changes. Accordingly, the factors presented in table 1-D are applied to the

monthly standard error approximations for levels, percentages, or rates; the magnitudes of the changes do not come

into play. Factors are not given for estimated changes between nonconsecutive months (except for changes of monthly

estimates 1 year apart); however, the standard errors may be

Table 1-C. Approximate standard errors for unemployment

rates by major characteristics

(In percent)

Characteristic Monthly

rate

Consecutive

month-tomonth change

Total ............................................................ 0.10 0.12

Men ......................................................... .14 .16

Men, 20 years and over ......................... .14 .15

Women .................................................... .14 .16

Women, 20 years and over ................... .14 .16

Both sexes, 16 to 19 years .................... .78 .97

White ........................................................... .11 .12

Black or African American ......................... .44 .49

Asian ........................................................... .46 .51

Hispanic or Latino ethnicity ........................ .34 .38

Married men, spouse present ................... .14 .15

Married women, spouse present............... .16 .18

Women who maintain families .................... .46 .52
196

assumed to be higher than the standard errors for consecutive monthly changes.

Standard errors of estimated levels using table 1-D. The

approximate standard error se(x) of x, an estimated monthly

level, can be obtained using the formula below, where a and

b are the parameters from table 1-D associated with a particular characteristic.

Illustration. Assume that, in a given a month, there are an

estimated 4 million unemployed men. Obtain the appropriate a and b parameters from table 1-D (Total or white; Men;

Unemployed). Use the formula for se(x) to compute an approximate standard error on the estimate of x = 4,000,000.

a = -0.0000321 b = 2970.55

Procedure for using table 1-D factors for levels. Table 1-D

gives factors that can be used to compute approximate standard errors of levels for other periods or for changes over

time. For each characteristic, factors f are given for:

Consecutive month-to-month changes

Changes in monthly estimates 1 year apart

Quarterly averages

Changes in consecutive quarterly averages

Yearly averages

Changes in consecutive yearly averages

For a given characteristic, the table 1-D factor is used in

the following formula, which also uses the a and b parameters from the same line of the table. A three-step procedure

for using the formula is given. The f in the formula is frequently called an adjustment factor, because it appears to

adjust a monthly standard error se(x). However, the x in the

formula is not a monthly level, but an average of several

monthly levels (see examples listed under Step 1, below).

 )(*)(*),( 2 = = + bxaxfxseffxse

where x is an average of monthly levels over a designated

period.

Step 1. Average monthly levels appropriately in order to

obtain x. Levels for 3 months are averaged for quarterly

averages, and those for 12 months are averaged for yearly

averages. For changes in consecutive averages, average over

the 2 months, 2 quarters, or 2 years involved. For changes in

monthly estimates 1 year apart, average the 2 months involved.

Step 2. Calculate an approximate standard error se(x),

treating the average x from step 1 as if it were an estimate of

level for a single month. Obtain parameters a and b from

table 1-D. (Note that, for some characteristics, an approximate standard error of level could instead be obtained from

table 1-B and used in place of se(x) in the formula.)

+= bxaxxse 2 )(

000,107)000,000,4(55.2970)000,000,4(0000321.0–)000,000,4( 2 se = + ≈

Step 3. Determine the standard error se (x, f) on the average level or on the change in level. Multiply the result from

step 2 by the appropriate factor f. The a and b parameters

used in step 2 and the factor f used in this step come from the

same line in table 1-D.

Illustration of a standard error computation for consecutive month change in level. Continuing the previous example, suppose that in the next month the estimated number

of unemployed men increases by 150,000, from 4,000,000

to 4,150,000.

Step 1. The average of the two monthly levels is x =

4,075,000.

Step 2. Apply the a and b parameters from table 1-D

(Total or white; Men; Unemployed) to the average x, treating it like an estimate for a single month.

a = -0.0000321 b = 2970.55

000,108)000,075,4(55.2970)000,075,4(0000321.0)000,075,4( 2 se −= + ≈

Step 3. Obtain f = 1.11 from the same row of table 1-D in

the column “Consecutive month-to-month change,” and multiply the factor by the result from step 2.

se = sef = ≈ 000,120000,108*11.1)000,075,4(*)000,150(

For an approximate 90-percent confidence interval, compute 1.645 * 120,000 ≈ 197,000. Subtract the number from

and add the number to 150,000 to obtain an interval

of -47,000 to 347,000. This is an approximate 90-percent

confidence interval for the true change, and since this interval includes zero, one cannot assert at this level of confidence that any real change has occurred in the unemployment level. The result also can be expressed by saying that

the apparent change of 150,000 is not significant at a 90-

percent confidence level.

Illustration of a standard error computation for quarterly

average level. Suppose that an approximate standard error

is desired for a quarterly average of the black or African

American employment level. Suppose that the estimated

employment levels for the 3 months making up the quarter

are 14,900,000, 15,000,000, and 15,100,000.

Step 1. The average of the three monthly levels is x =

15,000,000.

Step 2. Apply the a and b parameters from table 1-D

(Black; Total; Civilian labor force, employed, and not in

labor force) to the average x, treating it like an estimate for a

single month.

a = -0.0001514 b = 3454.72

000,133)000,000,15(72.3454)000,000,15(0001514.0)000.000,15( 2 se −= + ≈
197

Step 3. Obtain f = .87 from the same row of table 1-D in

the column “Quarterly averages,” and multiply the factor by

the result from step 2.

Illustration of a standard error computation for change in

quarterly level. Continuing the example, suppose that, in

the next quarter, the estimated average employment level for

blacks is 15,400,000, based on monthly levels of 15,300,000,

15,400,000, and 15,500,000. This is an estimated increase

of 400,000 over the previous quarter.

Step 1. The average of the two quarterly levels is x =

15,200,000.

Step 2. Apply the a and b parameters from table 1-D

(Black; Total; Civilian labor force, employed, and not in

labor force) to the average x, treating it like an estimate for a

single month.

a = -0.0001514 b = 3454.72

Step 3. Obtain f = .82 from the same row of table 1-D in

the column “Change in consecutive quarterly averages,” and

multiply the factor by the result from step 2.

For an approximate 95-percent confidence interval, compute 1.96 * 108,000 ≈ 212,000. Subtract the number from

and add the number to 400,000 to obtain an interval of

188,000 to 612,000. The interval excludes zero. Another

way of stating this is to observe that the estimated change of

400,000 clearly exceeds 1.96 standard errors, or 212,000.

One can conclude from these data that the change in

quarterly averages is significant at a 95-percent confidence

level.

Standard errors of estimated rates and percentages using

table 1-D. As shown in the formula below, the approximate

standard error se(p,y) of an estimated rate or percentage

p depends, in part, upon the number of persons y in its

base or denominator. Generally, rates and percentages

are not published unless the monthly base is greater

than 75,000 persons, the quarterly average base is greater

than 60,000 persons, or the yearly average base is greater

than 35,000 persons. The b parameter is obtained from

table 1-D. When the base y and the numerator of p are

from different categories within the table, use the b parameter from table 1-D relevant to the numerator of the rate or

percentage.

 Note that se(p,y)is in percent.

se = ≈ 000,116000,133*87.)000,000,15(

000,132)000,200,15(72.3454)000,200,15(0001514.0)000,200,15( 2 se −= + ≈

se = se = ≈ 000,108000,132*82.)000,200,15(*82.)000,400(

Illustration. For a given month, suppose y = 6,200,000

women 20 to 24 years of age are estimated to be employed.

Of this total, 2,000,000, or p = 32 percent, are classified as

part-time workers. Obtain the parameter b = 3095.55 from

the table 1-D row (Employment; Part-time workers) that is

relevant to the numerator of the percentage. Apply the formula to obtain:

For an approximate 95-percent confidence interval, compute 1.96 * 1.0 percent, and round the result to 2 percent.

Subtract this from and add this to the estimate of p = 32

percent to obtain an interval of 30 percent to 34 percent.

Procedure for using table 1-D factors for rates and percentages. Table 1-D factors can be used to compute approximate

standard errors on rates and percentages for other

periods or for changes over time. As for levels, there are three

steps in the procedure for using the formula.

 pp )100(*),(*),,(

y

b = = fypseffypse −

where p and y are averages of monthly estimates over a designated period. Note that se (p, y, f) 

is in percent.

Step 1. Appropriately average estimates of monthly rates

or percentages to obtain p, and also average estimates of

monthly levels to obtain y. Rates for 3 months are averaged

for quarterly averages, and those for 12 months are averaged

for yearly averages. For changes in consecutive averages,

average over the 2 months, 2 quarters, or 2 years

involved. For changes in monthly estimates 1 year apart,

average the 2 months involved.

Step 2. Calculate an approximate standard error

se (p, y), treating the averages p and y from step 1 as if they

were estimates for a single month. Obtain the b parameter

from the table 1-D row that describes the numerator of the

rate or percentage. (Note that, for some characteristics, an

approximate standard error could instead be obtained from

table 1-C and used in place of se (p, y) in the formula.)

Step 3. Determine the standard error se (p, y, f) on the

average level or on the change in level. Multiply the result

from step 2 by the appropriate factor f. The b parameter used

in step 2 and the factor f used in this step come from the same

line in table 1-D.

Illustration of a standard error computation for consecutive month change in percentage. Continuing the previous

example, suppose that, in the next month, 6,300,000 women

20 to 24 years of age are reported employed, and that

2,150,000, or 34 percent, are part-time workers.

pp )100(),(

y

b

ypse = −

( percent 0.1)32–100)(32( 000,200,6

55.3095

ypse ),( = ≈
198

Step 1. The month-to-month change is 2 percent = 34

percent - 32 percent. The average of the two monthly percentages of 32 percent and 34 percent is needed (p = 33

percent), as is the average of the two bases of 6,200,000 and

6,300,000 (y = 6,250,000).

Step 2. Apply the b = 3095.55 parameter from table 1-D

(Employment; Part-time workers) to the averaged p and y,

treating the averages like estimates for a single month.

( percent 0.1)33–100)(33( 000,250,6

55.3095

ypse ),( = ≈

Step 3. Obtain f =1 .24 from the same row of table 1-D in

the column “Consecutive month-to-month change,” and multiply the factor by the result from step 2.

se (2 percent) = 1.24 * 1.0 percent = 1.24 percent

For an approximate 95-percent confidence interval,

compute 1.96 * 1.24 percent, and round the result to 2.4

percent. Subtract this from and add this to the 2-percent

estimate of change to obtain an interval of -0.4 percent to

4.4 percent. Because this interval includes zero, it can be

concluded at a 95-percent confidence level that the change

is not significant.
199

Parameters Factors

Characteristic

a b

Consecutive Year-to-year Change in Change in

month-to- change Quarterly consecutive Yearly consecutive

month of monthly averages quarterly averages yearly

change estimates averages averages

Total or white

Total:

 Civilian labor force and

employed ........................... -0.0000167 3067.77 0.82 1.19 0.87 0.82 0.66 0.79

 Unemployed .......................... -.0000164 3095.55 1.11 1.35 .74 .91 .44 .59

 Not in labor force .................. -.0000087 1833.31 .82 1.16 .87 .80 .66 .79

Men:

 Civilian labor force, employed,

 and not in labor force ......... -.0000321 2970.55 .82 1.19 .87 .82 .66 .79

 Unemployed .......................... -.0000321 2970.55 1.11 1.35 .74 .91 .44 .59

Women:

 Civilian labor force, employed,

 and not in labor force ......... -.0000304 2782.44 .82 1.19 .87 .82 .66 .79

 Unemployed .......................... -.0000304 2782.44 1.11 1.35 .74 .91 .44 .59

Both sexes, 16 to 19 years:

 Civilian labor force, employed,

 and not in labor force ......... -.0000225 3095.55 .98 1.31 .82 .85 .57 .73

 Unemployed .......................... -.0000225 3095.55 1.24 1.39 .68 .88 .39 .52

Black or African American

Total:

 Civilian labor force, employed,

 and not in labor force ......... -.0001514 3454.72 .82 1.19 .87 .82 .66 .79

 Unemployed .......................... -.0001514 3454.72 1.11 1.35 .74 .91 .44 .59

Men:

 Civilian labor force, employed,

 and not in labor force ......... -.0003109 3356.66 .82 1.17 .83 .81 .62 .75

 Unemployed .......................... -.0003109 3356.66 1.11 1.35 .74 .91 .44 .59

Women:

 Civilian labor force, employed,

 and not in labor force ......... -.0002516 3061.85 .82 1.18 .86 .78 .67 .80

 Unemployed .......................... -.0002516 3061.85 1.11 1.35 .74 .91 .44 .59

Both sexes, 16 to 19 years:

 Civilian labor force, employed,

 and not in labor force ......... -.0016321 3454.72 .98 1.31 .80 .90 .53 .68

 Unemployed .......................... -.0016321 3454.72 1.24 1.39 .68 .88 .39 .52

Asian

Total:

 Civilian labor force, employed,

 and not in labor force ......... -.0003462 3198.15 .82 1.27 .85 .89 .58 .74

 Unemployed .......................... -.0003462 3198.15 1.11 1.48 .73 .90 .44 .58

Men:

 Civilian labor force, employed,

 and not in labor force ......... -.0007289 3198.15 .82 1.28 .83 .92 .55 .71

 Unemployed .......................... -.0007289 3198.15 1.11 1.42 .73 .92 .43 .56

Women:

 Civilian labor force, employed,

 and not in labor force ......... -.0006594 3198.15 .82 1.31 .85 .86 .61 .77

 Unemployed .......................... -.0006594 3198.15 1.11 1.49 .73 .89 .43 .59

Both sexes, 16 to 19 years:

 Civilian labor force, employed,

 and not in labor force ......... -.0041465 3198.15 .98 1.31 .82 .85 .57 .73

 Unemployed .......................... -.0041465 3198.15 1.24 1.38 .69 .85 .44 .56

Hispanic or Latino ethnicity

Total:

 Civilian labor force, employed,

 and not in labor force ......... -.0001412 3454.72 .82 1.19 .85 .81 .64 .77

 Unemployed .......................... -.0001412 3454.72 1.11 1.35 .73 .91 .44 .59

Men:

 Civilian labor force, employed,

 and not in labor force ......... -.0002528 3356.66 .82 1.19 .82 .86 .57 .72

 Unemployed .......................... -.0002528 3356.66 1.11 1.35 .74 .91 .44 .59

Table 1-D. Parameters and factors for computation of approximate standard errors
200

Parameters Factors

Characteristic

a b

Consecutive Year-to-year Change in Change in

month-to- change Quarterly consecutive Yearly consecutive

month of monthly averages quarterly averages yearly

change estimates averages averages

Hispanic or Latino

ethnicity—Continued

Women:

 Civilian labor force, employed,

 and not in labor force ......... -.0002664 3061.85 .82 1.19 .85 .80 .67 .80

 Unemployed .......................... -.0002664 3061.85 1.11 1.35 .72 .89 .42 .57

Both sexes, 16 to 19 years:

 Civilian labor force, employed,

 and not in labor force ......... -.0015280 3454.72 .98 1.32 .79 .88 .50 .68

 Unemployed .......................... -.0015280 3454.72 1.24 1.39 .68 .88 .39 .52

Employment

Educational attainment ........... -0.0000164 3095.55 .82 1.19 .85 .92 .59 .73

Marital status, men ................. -.0000321 2970.55 .82 1.21 .87 .88 .63 .77

Marital status, women ............ -.0000304 2782.44 .82 1.06 .88 .86 .65 .78

Women who maintain families -.0000304 2782.44 .82 1.16 .86 .91 .59 .73

Nonagricultural industries:

Total ......................................... -.0000164 3095.55 .82 1.16 .87 .82 .65 .79

 Wage and salary workers .. -.0000164 3095.55 .82 1.26 .87 .87 .62 .77

 Self-employed workers ....... -.0000164 3095.55 .82 1.14 .86 .94 .56 .73

 Unpaid family workers ........ -.0000164 3095.55 .98 1.30 .79 .94 .46 .65

Full-time workers .................... -.0000164 3095.55 1.11 1.35 .78 .88 .54 .66

Part-time workers ................... -.0000164 3095.55 1.24 1.42 .67 .88 .40 .50

Multiple jobholders .................. -.0000164 3095.55 1.11 1.26 .81 .92 .52 .66

At work

Total and nonagricultural

 industries:

Total ......................................... -.0000164 3095.55 .82 1.14 .86 .91 .60 .74

 1 to 4 or 5 to 14 hours ....... -.0000164 3095.55 1.24 1.36 .70 .89 .43 .54

 15 to 29 hours .................... -.0000164 3095.55 1.11 1.35 .74 .86 .47 .62

 30 to 34 or 35 to 39 hours . -.0000164 3095.55 1.24 1.42 .67 .88 .40 .50

 1 to 34 or 40 hours ............. -.0000164 3095.55 1.11 1.28 .78 .83 .55 .68

 41 to 48 or 49 to 59 hours . -.0000164 3095.55 1.24 1.35 .68 .87 .42 .51

 35+, 41+, or 60+ hours ...... -.0000164 3095.55 1.11 1.29 .74 .88 .47 .62

Part time for economic

reasons ................................. -.0000164 3095.55 1.21 1.38 .70 .87 .43 .55

Part time for noneconomic

 reasons ................................. -.0000164 3095.55 1.21 1.29 .75 .86 .50 .60

Unemployment

Educational attainment ........... -.0000164 3095.55 1.11 1.30 .72 .83 .46 .59

Marital status, men ................. -.0000321 2970.55 1.11 1.41 .76 .89 .45 .66

Marital status, women ............ -.0000304 2782.44 1.11 1.37 .74 .91 .42 .59

Women who maintain families -.0000304 2782.44 1.11 1.38 .75 .89 .45 .61

Industries and occupations ... -.0000164 3095.55 1.11 1.37 .73 .89 .45 .60

Full-time workers .................... -.0000164 3095.55 1.11 1.33 .76 .89 .47 .63

Part-time workers ................... -.0000164 3095.55 1.24 1.43 .67 .87 .38 .51

Less than 5 weeks ................. -.0000164 3095.55 1.11 1.30 .72 .83 .46 .59

5 to 14 weeks .......................... -.0000164 3095.55 1.24 1.45 .68 .91 .36 .49

15 to 26 weeks ....................... -.0000164 3095.55 1.24 1.45 .69 .90 .38 .54

15+ or 27+ weeks ................... -.0000164 3095.55 1.11 1.33 .77 .92 .46 .63

All reasons for unemployment,

 except temporary layoff ...... -.0000164 3095.55 1.11 1.30 .72 .83 .46 .59

On temporary layoff ............... -.0000164 3095.55 1.11 1.30 .68 .85 .44 .55

Not in the labor force

Total ......................................... -.0000087 1833.31 .82 1.11 .87 .78 .68 .79

 Persons who currently want

 a job and discouraged

 workers ................................ -.0000164 3095.55 1.24 1.23 .65 .85 .38 .48

Table 1-D. Parameters and factors for computation of approximate standard errors—Continued