- 4 -

Technical Note


   This release presents labor force and unemployment data from the 
Local Area Unemployment Statistics (LAUS) program (tables 1 and 2)
for 377 metropolitan statistical areas and metropolitan New England
City and Town Areas (NECTAs), including those in Puerto Rico.  Esti-
mates for over 30 metropolitan and NECTA divisions also are presented.
Nonfarm payroll employment estimates from the Current Employment Statis-
tics (CES) program (tables 3 and 4) are provided for most of the same 
areas.  State estimates were previously published in the news release, 
Regional and State Employment and Unemployment, and are republished in 
this release for ease of reference.  The LAUS and CES programs are both
federal-state cooperative endeavors.

Labor force and unemployment--from the LAUS program

   Definitions.  The labor force and unemployment data are based on the
same concepts and definitions as those used for the official national
estimates obtained from the Current Population Survey (CPS), a sample
survey of households that is conducted for the Bureau of Labor Statis-
tics (BLS) by the U.S. Census Bureau.  The labor force includes both the
employed and the unemployed.  Employed persons are those who did any work
at all for pay or profit in the survey reference week (the week including
the 12th of the month) or worked 15 hours or more without pay in a family
business or farm, plus those not working who had a job from which they
were temporarily absent, whether or not paid, for such reasons as labor-
management dispute, illness, or vacation.  Unemployed persons are those
who did not work at all (in the reference week), had actively looked for
a job (sometime in the 4-week period ending with the survey reference
week), and were currently available for work; persons on layoff expecting
recall need not be looking for work to be counted as unemployed.

   Method of estimation.  Effective January 2005, estimates for all census
divisions, states, the District of Columbia, the Los Angeles-Long Beach-
Glendale metropolitan division, and New York City were produced using up-
dated time-series models with real-time benchmarking.  Model-based estima-
tion was extended to the following areas and the respective balances-of-
state:  Chicago-Naperville-Joliet, IL Metropolitan Division; Cleveland-
Elyria-Mentor, OH Metropolitan Statistical Area; Detroit-Warren-Livonia,
MI Metropolitan Statistical Area; Miami-Miami Beach-Kendall, FL Metropol-
itan Division; New Orleans-Metairie-Kenner, LA Metropolitan Statistical
Area; and Seattle-Bellevue-Everett, WA Metropolitan Division.  This will
improve the statistical basis of the estimation for these areas and pro-
vide important tools for analysis, such as measures of error and season-
ally adjusted series.  For all other substate areas, estimates are pre-
pared through indirect estimation procedures.  Employment estimates, which
are based largely on "place of work" estimates from the CES program, are
adjusted to refer to place of residence as used in the CPS.  Unemployment
estimates are aggregates of persons previously employed in industries
covered by state unemployment (UI) laws and entrants to the labor force
data from the CPS.  The substate estimates of employment and unemployment,
which geographically exhaust the entire state, are adjusted proportionally
to ensure that they add to the independently estimated state or balance-
of-state totals.  A detailed description of the estimation procedures is
available from BLS upon request.

   Annual revisions.  Labor force and unemployment data shown for the prior
year reflect adjustments made at the end of each year, usually implemented
with January estimates.  The adjusted estimates reflect updated population
data from the U.S. Census Bureau, any revisions in the other data sources,
and model reestimation at the state and selected area level.  All substate
area estimates are adjusted to add to the revised model-based estimates.

                                  - 5 -

Employment--from the CES program

   Definitions.  Employment data refer to persons on establishment payrolls
who receive pay for any part of the pay period that includes the 12th of the
month.  Persons are counted at their place of work rather than at their place
of residence; those appearing on more than one payroll are counted on each
payroll.  Industries are classified on the basis of their principal activity
in accordance with the 2007 version of the North American Industry Classifi-
cation System.

   Method of estimation.  The employment data are estimated using a "link
relative" technique in which a ratio (link relative) of current-month em-
ployment to that of the previous month is computed from a sample of estab-
lishments reporting for both months.  The estimates of employment for the
current month are obtained by multiplying the estimates for the previous 
month by these ratios.  Small-domain models are used as the official esti-
mators for the approximately 39 percent of CES published series which have
insufficient sample for direct sample-based estimates.

   Annual revisions.  Employment estimates are adjusted annually to a com-
plete count of jobs, called benchmarks, derived principally from tax reports
that are submitted by employers who are covered under state UI laws.  The
benchmark information is used to adjust the monthly estimates between the
new benchmark and the preceding one and also to establish the level of em-
ployment for the new benchmark month.  Thus, the benchmarking process estab-
lishes the level of employment, and the sample is used to measure the month-
to-month changes in the level for the subsequent months.
     
Reliability of the estimates
     
   The estimates presented in this release are based on sample survey and
administrative data and thus are subject to sampling and other types of
errors.  Sampling error is a measure of sampling variability--that is, vari-
ation that occurs by chance because a sample rather than the entire popula-
tion is surveyed.  Survey data also are subject to nonsampling errors, such
as those which can be introduced into the data collection and processing
operations.  Estimates not directly derived from sample surveys are subject
to additional errors resulting from the special estimation processes used.
The sums of individual items may not always equal the totals shown in the
same tables because of rounding.  With respect to the LAUS program, unem-
ployment rates are computed from unrounded data rather than from data
that may be displayed in the tables; differences, however, are generally
insignificant.

   Labor force and unemployment estimates.  Model-based error measures, in-
cluding for over-the-month change, are available for states on the BLS Web 
site at http://www.bls.gov/lau/lastderr.htm.  Measures of nonsampling error
are not available, but additional information on the subject is provided in
Employment and Earnings Online at http://www.bls.gov/opub/ee/home.htm.

   Employment estimates.  Measures of sampling error for state CES data at
the supersector level and for metropolitan area CES data at the total nonfarm
level are available on the BLS Web site at http://www.bls.gov/sae/790stderr.
htm.  Information on recent benchmark revisions for states is available at
http://www.bls.gov/sae/.

                                  - 6 -

Area definitions

   The substate area data published in this release reflect the standards
and definitions established by the U.S. Office of Management and Budget on
November 20, 2007.  A detailed list of the geographic definitions is avail-
able on the Internet at http://www.bls.gov/lau/lausmsa.htm.

Additional information

   More complete information on the technical procedures used to develop
these estimates and additional data appear in Employment and Earnings
Online.

   Estimates of unadjusted and seasonally adjusted labor force and unemploy-
ment data for states, census regions and divisions, and eight areas are avail-
able in the news release, Regional and State Employment and Unemployment.  Es-
timates of labor force and unemployment for all states, metropolitan areas,
labor market areas, counties, cities with a population of 25,000 or more, and
other areas used in the administration of various federal economic assistance
programs are available on the BLS Web site at http://www.bls.gov/lau/.  Employ-
ment data from the CES program are available at http://www.bls.gov/sae/.

   Information in this release will be made available to sensory impaired in-
dividuals upon request.  Voice phone:  (202) 691-5200; TDD message referral
phone:  1-800-877-8339.