Technical Notes for 2002 OES Estimates
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, by
industry, in the United States. (Guam, Puerto Rico, and the Virgin
Islands also are surveyed, but their data are not included in this release.)
In 2002, the OES survey switched from industry coding based on the
Standard Industrial Classification (SIC) system to that based on the
North American Industry Classification System (NAICS). The
nationwide response rate for the 2002 survey was 78 percent for
establishments, covering 71 percent of employment.
In November 2002, the OES survey changed from an annual survey
of 400,000 establishments to a semiannual survey of 200,000
establishments. The OES survey samples and contacts establishments
in May and November of each year and, over 3 years, contacts
approximately 1.2 million establishments. The full 3-year sample
allows the production of estimates at fine levels of geographic,
industrial, and occupational detail.
In order to maintain adequate geographic, industrial, and
occupational coverage through the implementation of NAICS and
semiannual sampling, the 2002 data were combined with the annual
samples from 1999, 2000, and 2001 for a total sample size of
approximately 1.4 million establishments. Estimates from the OES
are based on data collected using the Standard Occupational
Classification (SOC) system. A brief description of this classification
system is provided below.
The Occupational Classification Standard for 2002
In 1999, the OES survey began using the Office of Management and
Budget's (OMB) occupational classification system, the Standard
Occupational Classification (SOC) system. The SOC system is the
first OMB-required occupational classification system for federal
agencies. The OES survey categorizes workers in 1 of about 770
detailed occupations. Together, these detailed occupations comprise
22 major occupational groups. The major groups are as follows:
- Management occupations
- Business and financial operations occupations
- Computer and mathematical occupations
- Architecture and engineering occupations
- Life, physical, and social science occupations
- Community and social services occupations
- Legal occupations
- Education, training and library occupations
- Arts, design, entertainment, sports, and media occupations
- Healthcare practitioners and technical occupations
- Healthcare support occupations
- Protective service occupations
- Food preparation and serving related occupations
- Building and grounds cleaning and maintenance occupations
- Personal care and service occupations
- Sales and related occupations
- Office and administrative support occupations
- Farming, fishing, and forestry, occupations
- Construction, and extraction occupations
- Installation, maintenance, and repair occupations
- Production occupations
- Transportation and material moving occupations
- Military specific occupations (not surveyed in OES).
For more information about the SOC, please see the Bureau of Labor Statistics (BLS) Web site at http://www.bls.gov/soc.
The industry coding system for 2002
In 2002 the OES survey switched from using the Standard Industrial
Classification (SIC) System to using the North American Industry
Classification System (NAICS). Due to differences in NAICS and SIC
structures, OES industry data for 2002 are not comparable with the
SIC-based data for earlier years. For more information about NAICS,
see the BLS Web site at http://www.bls.gov/bls/naics.htm. An
establishment is defined as an economic unit that processes goods or
provides services, such as a factory, mine, or store. The establishment
is generally at a single physical location and is engaged primarily in one
type of economic activity.
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.
The OES survey includes establishments in NAICS sectors 11
(logging and agricultural support activities only), 21, 22, 23, 31-33, 42,
44-45, 48-49, 51, 52, 53, 54, 55, 56, 61, 62, 71, 72, 81 (except private
households), state government, and local government. Data for the
U.S. Postal Service and the federal government are universe counts
obtained from the Postal Service and the Office of Personnel
Management, respectively.
BLS funds the survey and provides the procedures and technical
support, while the State Employment Security Agencies (SESAs)
collect the data. BLS produces cross-industry NAICS estimates for
the nation, states, and metropolitan statistical areas (MSAs). NAICS
estimates are produced primarily at the 4-digit level with some 5-digit
exceptions. BLS releases all cross-industry and national estimates, and
the SESAs release industry estimates at the state and MSA levels.
The OES survey defines employment as the number of workers
who can be classified as full-time or part-time employees, including
workers on paid vacations or other types of 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.
State Unemployment Insurance (UI) files provide the universe from
which the OES survey draws its sample. The employment benchmarks
are obtained from reports submitted by employers to the UI program.
In some non-manufacturing industries, supplemental sources are used
for establishments not reporting to the UI program. The OES survey
sample is stratified by area, industry, and size class. Size classes are
defined as follows:
Size class |
Number of employees |
1 |
1 to 4 |
2 |
5 to 9 |
3 |
10 to 19 |
4 |
20 to 49 |
5 |
50 to 99 |
6 |
100 to 249 |
7 |
250 and above |
UI reporting units with 250 or more employees are sampled with
virtual certainty across a 3-year period. Generally, one-sixth of the
certainty units are sampled in each panel in each state.
Concepts
Occupational Employment is the estimate of total wage and salary
employment in an occupation across the industries in which that
occupation was reported. The OES survey form sent to an
establishment contains between 50 and 225 SOC occupations selected
on the basis of the sampled establishment's industry classification
and size class. To reduce paperwork and respondent burden, no
survey form contains every SOC occupation. Thus, data for specific
occupations are collected primarily from establishments in industries
that are the predominant employers of workers in those occupations.
Each survey form is structured, however, to allow a respondent to
provide detailed occupational information for each worker at the
establishment; that is, workers in unlisted occupations can have their
occupations added to the survey form.
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, tips, and on-call pay are included. Excluded are
back pay, jury duty pay, overtime pay, severance pay, shift
differentials, non-production bonuses, employer cost for
supplementary benefits, and tuition reimbursements.
The OES survey collects wage data in 12 intervals. Employers report the number of employees in an occupation for each wage range. The wage intervals used for the 2002 survey are as follows:
Interval |
Hourly Wages |
Annual Wages |
Range A |
Under $6.75 |
Under $14,040 |
Range B |
$6.75 to $8.49 |
$14,040 to $17,679 |
Range C |
$8.50 to $10.74 |
$17,680 to $22,359 |
Range D |
$10.75 to $13.49 |
$22,360 to $28,079 |
Range E |
$13.50 to $16.99 |
$28,080 to $35,359 |
Range F |
$17.00 to $21.49 |
$35,360 to $44,719 |
Range G |
$21.50 to $27.24 |
$44,720 to $56,679 |
Range H |
$27.25 to $34.49 |
$56,680 to $71,759 |
Range I |
$34.50 to $43.74 |
$71,760 to $90,999 |
Range J |
$43.75 to $55.49 |
$91,000 to $115,439 |
Range K |
$55.50 to $69.99 |
$115,440 to $145,599 |
Range L |
$70.00 and over |
$145,600 and over |
A Mean (average) wage value is calculated for each wage interval
based on occupational wage data collected by the BLS Office of
Compensation and Working Conditions for the National
Compensation Survey (NCS). These interval mean wage values are
then attributed to all workers reported in the interval. To calculate
the mean wage of each occupation, total weighted wages are summed
across all intervals and divided by the occupation's weighted survey
employment.
The mean wage value for the highest wage interval, $70.00 and
over, is calculated after excluding data for pilots. Pilots comprise a
large portion of the employment from the NCS survey that falls into
the highest interval, and about one percent of the workers reported
for the OES survey makes $70.00 and over. Since pilots work much
fewer hours than workers in other occupations, their hourly wage
rates are much higher than other occupations. After excluding pilots
from the calculation, the mean wage for the highest interval was
computed separately for 1999, 2000, 2001, and 2002. Then the
average of these four mean wages was derived and used for all of the
$70.00 and over data in the 2002 survey. The wages for this interval
do not go through any wage updating procedures.
Annual wage. Many employees are paid at an hourly rate by their
employers and may work more than or less than 40 hours per week.
The annual wage estimates in this release are calculated by
multiplying the mean hourly wage by a "year-round, full-time" figure
of 2,080 hours (52 weeks by 40 hours). Thus, the annual wage
estimates may not represent the actual annual pay received by the
employee if they work more or less than 2,080 hours per year.
Alternatively, some workers are paid based on an annual amount, but
they generally do not work the usual 2,080 hours per year. Since the
OES survey does not collect the actual number of hours worked, the
hourly rate cannot be calculated with a reasonable degree of confidence
from the annual wages. For this reason, the annual salary is directly
calculated from reported survey data, and only annual wages are
estimated for these occupations. Occupations that typically have a
work year of less than 2,080 hours include musical and entertainment
occupations, pilots and flight attendants, and teachers.
Hourly versus annual wage reporting. 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 establishment can
reference either the hourly or the annual rate, but they are instructed
to report the hourly rate for part-time workers.
Estimation methodology
Beginning in the fourth quarter of 2002, the OES survey samples
approximately 200,000 establishments semiannually in the second
and fourth quarters of the year, for a combined sample of 1.2 million
different establishments over six semiannual panels. Until 2002, the
survey sampled approximately 400,000 establishments in the fourth
quarter of each year, for a 3-year combined sample size of 1.2 million.
While estimates can be made from a single year or 2 years of data,
the OES survey has been designed to produce estimates at a desired
level of precision using the full 3 years of data. The 3-year sample
allows the production of estimates at fine levels of geographical,
industrial, and occupational detail. Since the 2002 sample was the
first time that 200,000 establishments were sampled, the data were
combined with annual survey data from 1999, 2000, and 2001, for
a combined sample of approximately 1.4 million to provide adequate
coverage of the sampling frame for these detailed estimates.
Producing estimates using the 3 years of sample data provides
significant sampling error reductions (particularly for small
geographic areas and occupations); however, it also has some quality
limitations in that it requires the adjustment of earlier years' data to the
current reference period, a procedure referred to as "wage updating."
Wage Updating. As noted above, combining multiple years of data
has both statistical advantages and limitations. Significant reductions
in sampling error can be achieved by taking advantage of 3 years of
data, which covers over 70 percent of the employment in the United
States. This feature is particularly important in improving the
reliability of estimates for small domains in the population (that is,
wage and employment estimates for detailed occupations in small
areas). Combining multiple years of data also has been necessary to
obtain full coverage of establishments with 250 or more workers that
are sampled with certainty.
Starting with the 1997 estimates, the OES program has used the
over-the-year fourth-quarter wage changes from the BLS
Employment Cost Index (ECI) to adjust prior year survey data before
combining it with the current year's data. The wage updating
procedure assumes that each occupation's wage, as measured in the
earlier years, moves according to the average movement of its
occupational division and that there are no major geographic or
detailed occupational differences.
2002 OES survey estimates. The 2002 OES survey estimates are
based on data collected from establishments for the 1999, 2000, 2001,
and 2002 samples. The 2002 estimates use the wage-updating
methodology introduced in 1997. In addition, the 2002 estimates use
the estimation methodology introduced in 1997, which uses a "nearest
neighbor" imputation approach for nonresponse and applies
employment benchmarks at the state-MSA/4-digit NAICS (with 5-
digit exceptions) /size class level.
Reliability of the estimates. Statistics based on establishment
surveys are subject to both sampling and nonsampling error. When
a sample of the population is surveyed, there is a chance that the
sample estimate of a characteristic may differ from the population
value of that characteristic. The difference between the sample
estimate and the population value will vary depending on the
particular sample selected. This variability is measured by the
sampling error (SE). If the sampling and estimation process using the
same survey design was repeated, 90 percent of the intervals created
by adding and subtracting 1.645 standard errors from the sample
estimate would include the population value. This interval is called
a 90-percent confidence interval.
The OES survey produces estimates of the relative standard error
(RSE). The RSE is defined as the SE divided by the estimated value
as computed from the sample. This statistic provides a measure of
the relative precision of the sample estimates. The SE may be
obtained by multiplying the RSE by the sample estimate. RSE
estimates are produced for both occupational employment and mean
wage estimates. The employment RSE values are estimated using a
subsample replication technique known as the Jackknife (random
group) variance estimation method. The mean wage RSE values are
estimated using a variance components model that accounts for both
the observed and unobserved components of the wage data. The
variances of the unobserved components of the wage data are
calculated from the BLS National Compensation Survey. In general,
estimates involving many establishments have lower relative standard
errors than estimates involving few establishments. If the
distributional assumptions of the models are violated, the resulting
confidence interval may not reflect the prescribed level of confidence.
Additional information
The 2002 OES national data by occupation, comparable to data
in table 1, will be available soon on the Internet (http://www.bls.gov/oes). Users also may access each occupation's definition and
percentile wages. The 2002 cross-industry data for states and
metropolitan areas will be available on the BLS Web site in late
November. Industry staffing patterns at the 4- and 5-digit NAICS
levels also will be available from the Internet beginning in late
November. These data will include industry-specific occupational
employment and wage data.
For additional information, contact the Office of Employment and
Unemployment Statistics, Division of Occupational Employment
Statistics, Room 2135, 2 Massachusetts Avenue, NE, Washington,
DC, 20212; telephone: 202-691-6569; e-mail: OES staff.
Information in this release will be made available to sensory
impaired individuals upon request. Voice phone: 202-691-5200;
TDD message referral phone number: 1-800-877-8339.
2002 National Occupational Employment and Wage Estimates
2002 State Occupational Employment and Wage Estimates
2002 Metropolitan Area Occupational Employment and Wage Estimates
2002 National Industry-Specific Occupational Employment and Wage Estimates
List of Occupations in SOC Code Number Order
List of Occupations in Alphabetical Order
Download 2002 Occupational Employment and Wage Estimates in Zipped Excel files
Last Modified Date: January 10, 2007