Technical Note
Scope of the survey
The Occupational Employment Statistics (OES) survey is a semiannual
mail survey measuring occupational employment and wage rates for wage
and salary workers in nonfarm establishments in the United States. OES
data available from BLS include cross-industry occupational employment
and wage estimates for the nation; over 500 areas, including states
and the District of Columbia, metropolitan statistical areas (MSAs),
metropolitan divisions, nonmetropolitan areas, and territories; national
industry-specific estimates at the NAICS sector, 3-, 4-, and selected
5-digit industry levels; and national estimates by ownership across all
industries and for schools and hospitals.
The OES survey is a cooperative effort between BLS and the State
Workforce Agencies. BLS funds the survey and provides the procedures
and technical support, while the State Workforce Agencies (SWAs) collect
most of the data. OES estimates are constructed from a sample of about
1.2 million establishments. Each year, forms are mailed to two semiannual
panels of approximately 200,000 sampled establishments, one panel in May
and the other in November. May 2010 estimates are based on responses from
six semiannual panels collected over a 3-year period: May 2010, November
2009, May 2009, November 2008, May 2008, and November 2007. The overall
national response rate for the six panels is 78.2 percent based on
establishments and 74.4 percent based on employment. The unweighted
employment of sampled establishments across all six semiannual panels
represents approximately 62.6 percent of total national employment.
The occupational coding system
The OES survey categorizes workers into nearly 800 detailed occupations
based on the Office of Management and Budget’s Standard Occupational
Classification (SOC) system; together, these detailed occupations make up
22 of the 23 SOC major occupational groups. Major group 55, Military Specific
Occupations, is not included. The May 2010 OES estimates mark the first set
of estimates based in part on data collected using the 2010 SOC system.
Previous estimates were based on the 2000 SOC.
Almost all the occupations in this release are 2010 SOC occupations;
however, some are not. In these cases, an estimate for a temporary
occupation was created from data reported for one or more occupations in
the 2000 SOC combined with data reported for one or more 2010 SOC occupa-
tions. Some occupations have the same title as a 2010 SOC occupation, but
not the same content. These occupations are marked with an asterisk (*)
and given a temporary code for the OES data. The May 2012 OES data will
reflect the full set of detailed occupations in the 2010 SOC. For a list
of all occupations, including 2010 SOC occupations, and how data collected
on two structures were combined, see the OES Frequently Asked Questions
online at www.bls.gov/oes/oes_ques.htm#Ques41.
For more information about the SOC system, please see the Bureau of
Labor Statistics Web site at www.bls.gov/soc/.
The industry coding system
The OES survey uses the 2007 North American Industry Classification
System (NAICS). For more information about NAICS, see the BLS Web site at
www.bls.gov/bls/naics.htm.
The OES survey excludes the majority of the agricultural sector, with
the exception of logging (NAICS 113310), support activities for crop
production (NAICS 1151), and support activities for animal production
(NAICS 1152). Private households (NAICS 814) also are excluded. OES federal
government data include the U.S. Postal Service and the federal executive
branch only. All other industries, including state and local government,
are covered by the survey.
The OES survey covers all full- and part-time wage and salary workers
in nonfarm industries. The survey does not include the self-employed,
owners and partners in unincorporated firms, household workers, or unpaid
family workers.
Survey sample
The OES survey draws its sample from state unemployment insurance (UI)
files. Supplemental sources are used for rail transportation (NAICS 4821)
and Guam because they do not report to the UI program. The OES survey sample
is stratified by metropolitan and nonmetropolitan area, industry, and size.
To provide the most occupational coverage, larger employers are more likely
to be selected than smaller employers. An annual census is taken of the executive
branch of the federal government, the U.S. Postal Service, and state government.
Concepts
Occupational employment is the estimate of total wage and salary employment
in an occupation. The OES survey defines employment as the number of workers
who can be classified as full- or part-time employees, including workers on
paid vacations or other types of paid leave; workers on unpaid short-term
absences; salaried officers, executives, and staff members of incorporated
firms; employees temporarily assigned to other units; and employees for whom
the reporting unit is their permanent duty station, regardless of whether that
unit prepares their paycheck.
Wages for the OES survey are straight-time, gross pay, exclusive of premium
pay. Base rate; cost-of-living allowances; guaranteed pay; hazardous-duty pay;
incentive pay, including commissions and production bonuses; and tips are
included. Excluded are overtime pay, severance pay, shift differentials, non-
production bonuses, employer cost for supplementary benefits, and tuition reim-
bursements.
OES receives wage rate data for the federal government, the U.S. Postal
Service, and some state governments. For the remaining establishments, the OES
survey collects wage data in 12 intervals. For each occupation, respondents are
asked to report the number of employees paid within specific wage intervals.
The intervals are defined both as hourly rates and the corresponding annual
rates, where the annual rate for an occupation is calculated by multiplying the
hourly wage rate by a typical work year of 2,080 hours. The responding establish-
ments are instructed to report the hourly rate for part-time workers, and to
report annual rates for occupations that are typically paid at an annual rate but
do not work 2,080 hours per year, such as teachers, pilots, and flight attendants.
Other workers, such as some entertainment workers, are paid hourly rates, but
generally do not work 40 hours per week, year round. For these workers, only an
hourly wage is reported.
Estimation methodology
The OES survey is designed to produce estimates by combining six panels of
data collected over a 3-year period. With the exception of the May 2008 panel,
each OES panel includes approximately 200,000 establishments. Due to budget
constraints, the May 2008 sample was reduced to approximately 174,000 establish-
ments. The full six-panel sample of nearly 1.2 million establishments allows the
production of estimates at detailed levels of geography, industry, and occupation.
Wage updating. Significant reductions in sampling errors are obtained by
combining six panels of data, particularly for small geographic areas and occu-
pations. Wages for the current panel need no adjustment. However, wages in the
five previous panels need to be updated to the current panel's reference period.
The OES program uses the BLS Employment Cost Index (ECI) to adjust survey data
from prior panels before combining them with the current panel's data. The wage
updating procedure adjusts each detailed occupation's wage rate, as measured in
the earlier panel, according to the average movement of its broader occupational
division.
Imputation. About 20 percent of establishments do not respond for a given
panel. A "nearest neighbor" hot deck imputation procedure is used to impute
missing occupational employment totals. A variant of mean imputation is used to
impute missing wage distributions.
Weighting and benchmarking. The sampled establishments are weighted to
represent all establishments for the reference period. Weights are further
adjusted by the ratio of employment totals (the average of November 2009 and
May 2010 employment) from the BLS Quarterly Census of Employment and Wages to
employment totals from the OES survey.
For more information
Answers to frequently asked questions about the OES data are available at
www.bls.gov/oes/oes_ques.htm. Detailed technical information about the OES
survey is available in our Survey Methods and Reliability Statement on the BLS
website at www.bls.gov/oes/current/methods_statement.pdf.
United States Department of Labor
