Technical Notes for May 2003 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 May 2003 survey
was 79 percent for establishments, covering 72 percent of weighted
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, May 2003 data were combined with samples
from November 2002, 2001, 2000, and a subset of certainty units
collected in 1999. Note that May 2003 and November 2002 are
semiannual samples while 2001 and 2000 are annual samples. Data
from 1999 were added to provide complete coverage of the certainty
strata. The total sample size is 1.2 million establishments. Estimates
from the OES survey are based on data collected using the Standard
Occupational Classification (SOC) system. A brief description of
this classification system is provided below.
The Standard Occupational Classification system 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 the
770 detailed occupations. Together, these detailed occupations
comprise 23 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 BLS Web site at http://www.bls.gov/soc
The industry coding system As noted earlier, in 2002, the OES survey switched from using
the Standard Industrial Classification (SIC) system to using the
North American Industry Classification System (NAICS). For
more information about NAICS, see the BLS Web site at
http://www.bls.gov/bls/naics.htm.
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. 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.
Survey coverageBLS funds the survey and provides the procedures and technical
support, while the State Workforce Agencies (SWAs) collect the
data. BLS produces cross-industry NAICS estimates for the nation,
states, and metropolitan statistical areas (MSAs). NAICS estimates
are produced for 3-digit, 4-digit, and selected 5-digit industry levels.
BLS releases all cross-industry and national estimates, and the SWAs
release industry estimates at the state and MSA levels.
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. 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 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. Some states,
however, sampled more than one-sixth of their certainty units in the
May 2003 survey to make up for a shortfall in a previous sample.
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 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.
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, unlisted occupations can be 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 May 2003 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 |
Mean hourly wage. The mean hourly wage rate for an occupation
is the total wages that all workers in the occupation earn in an hour
divided by the total employment of the occupation. To calculate the
mean hourly wage of each occupation, total weighted hourly wages are
summed across all intervals and divided by the occupation's weighted
survey employment. The mean wage for each interval is based on occupational
wage data collected by the BLS Office of Compensation and
Working Conditions for the National Compensation Survey (NCS).
The mean hourly 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 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 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 rate for the highest interval was computed
separately for May 2003, November 2002, 2001, 2000, and 1999.
Then the average of these five mean wage rates was derived and used for
all of the $70.00 and over data in the May 2003 survey. The wage rates
for this interval do not go through any wage updating procedures.
Percentile wage. The p-th percentile wage range for an occupation
is the wage where p percent of all workers earn that amount or less
and where (100-p) percent of all workers earn that amount or more.
This statistic is calculated by uniformly distributing the workers
inside each wage interval, ranking the workers from lowest paid to
highest paid, and calculating the product of the total employment for
the occupation and the desired percentile to determine the worker
that earns the p-th percentile wage rate.
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.
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, 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, hourly rates cannot
be calculated with a reasonable degree of confidence from annual rates.
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 November 2002, the OES survey samples
approximately 200,000 establishments semiannually in November
and May of each 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, or 6 panels, of data. The 3-year
sample allows the production of estimates at fine levels of geographic,
industrial, and occupational detail.
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 year's 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.
May 2003 OES survey estimates. The May 2003 OES survey
estimates are based on data collected from establishments in the
November 2002, 2001, and 2000 samples plus a subset of certainty
units collected in 1999. The May 2003 estimates used the wageupdating
methodology introduced in 1997. In addition, a "nearest
neighbor" hot deck imputation procedure was used to impute
occupational employment totals for establishments that reported no
employment data. For establishments that reported (or imputed)
occupational employment totals but did not report an employment
distribution across the wage intervals, a variation of mean imputation
was used to impute the distribution. During estimates processing,
OES employment data were benchmarked to the average employment
for May 2003 and November 2002 from the BLS Quarterly Census
of Employment and Wages.
Reliability of the estimates. Estimates calculated from a sample
survey are subject to two types of error: sampling and nonsampling.
Sampling error occurs when estimates are calculated from a subset
(i.e., sample) of the population instead of the full population. When
a sample of the population is surveyed, there is a chance that the
sample estimate of the characteristic of interest may differ from the
population value of that characteristic. Differences between the
sample estimate and the population value will vary depending on the
sample selected. This variability can be estimated by calculating the
standard error (SE) of the sample estimate. If we were to repeat the
sampling and estimation process countless times using the same
survey design, approximately 90 percent of the intervals created by
adding and subtracting 1.645 SEs from the sample estimate would
include the population value. These intervals are called 90-percent
confidence intervals. The OES survey, however, usually uses the
relative standard error (RSE) of a sample estimate instead of its SE
to measure sampling error. RSE is defined as the SE of a sample
estimate divided by the sample estimate itself. This statistic provides
the user with a measure of the relative precision of the sample
estimate. RSEs are calculated for both occupational employment and
mean wage rate estimates. Occupational employment RSEs are
calculated using a subsample, random group replication technique
called the Jackknife. Mean wage rate RSEs are calculated using a
variance components model that accounts for both the observed and
unobserved components of the wage data. The variances of the
unobserved components are estimated using wage data from the BLS
National Compensation Survey. In general, estimates based on many
establishments have lower RSEs than estimates based on few
establishments. If the distributional assumptions of the models are
violated, the resulting confidence intervals may not reflect the
prescribed level of confidence.
Nonsampling error occurs for a variety of reasons, none of which
are directly connected to sampling. Examples of nonsampling error
include: nonresponse, data incorrectly reported by the respondent,
mistakes made in entering collected data into the database, and
mistakes made in editing and processing the collected data.
Additional information
The May 2003 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 May 2003 cross-industry data
for states and metropolitan areas will be available on the BLS Web
site in early May. Industry staffing patterns at the 3-, 4-, and selected
5-digit NAICS levels also will be available from the Internet beginning
in early May. 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.
May 2003 National Occupational Employment and Wage Estimates
May 2003 State Occupational Employment and Wage Estimates
May 2003 Metropolitan Area Occupational Employment and Wage Estimates
May 2003 National Industry-Specific Occupational Employment and Wage Estimates
List of Occupations in SOC Code Number Order
List of Occupations in Alphabetical Order
Download May 2003 Occupational Employment and Wage Estimates in Zipped Excel files
Technical notes
Last Modified Date: January 10, 2007
