Occupational Employment Statistics

Technical Notes for 1999 OES Estimates

Scope of the survey

The Occupational Employment Statistics (OES) survey is an annual mail survey measuring occupational employment and wage rates for wage and salary workers in nonfarm establishments, by industry. The OES survey samples and contacts approximately 400,000 establishments each year and, over 3 years, contacts approximately 1.2 million establishments. The reference period for each year's survey is the fourth quarter of that year. While estimates can be made from a single year of data, the OES survey has been designed to produce estimates using the full 3 years of sample. (See Estimation methodology section.) The full sample allows the production of estimates at fine levels of geography, industry, and occupational detail.

BLS and the Employment and Training Administration (ETA) provide the funding for the survey. BLS provides the procedures and technical support, while the State Employment Security Agencies (SESAs) collect the data. The SESAs produce industry-specific estimates for states and local areas. BLS produces cross industry and 2- and 3- digit SIC industry estimates for the nation, states, and metropolitan statistical areas (MSAs).

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 survey excludes the self-employed, owners/partners of unincorporated firms, and unpaid family workers. Employees are reported in the occupation in which they are working, not necessarily for which they were trained.

The OES survey currently uses the Standard Industrial Classification (SIC) system to classify all establishments. 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 scope of the survey includes establishments in SIC codes 07, 10, 12 to 17, 20 to 42, 44 to 65, 67, 70, 72, 73, 75, 76, 78 to 84, 86, 87, and 89. This scope covers agricultural services; mining; construction; manufacturing; transportation and public utilities; wholesale and retail trade; finance, insurance, and real estate; and services. Data for the postal service (SIC code 43) and federal government are universe counts obtained from the Office of Personnel Management.

States' 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 nonmanufacturing 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 certainty across a 3-year period. Many States sample one-third of their certainty units each year. However, there are some States that sample more than one-third of their certainty units during one survey year.

In 1997 establishments in size classes 2 to 6 were selected based on a probability sample. The sampling weights in size class 2 were adjusted to account for the employment in size class 1. In 1998, the OES survey began sampling establishments in size class 1; thus, establishments in all size classes are now represented in the probability sample.

New Occupational Classification Standards for 1999: In 1999 the OES survey began using the Office of Management and Budget's new occupational classification system — the Standard Occupational Classification System (SOC). The SOC system is the first OMB required occupational classification system for Federal agencies. The OES survey uses 22 major occupational groups from the SOC to categorize workers in one of almost 770 detailed occupations. Previous years' data was cross-walked to the new classification system when possible and used in producing wage estimates for these occupations. Of the occupations listed in Table 1, wages for 374 of the matched occupations are estimated using data from the 1997, 1998, and 1999 surveys. The remaining occupations are either new SOC occupations, or are slightly different from similar occupations in the old OES structure; wages for these occupations are estimated from a single year of data only. In order to maintain employment additivity, all occupational employment estimates are based only on the data collected in the 1999 survey. The major groups of the new SOC system are as follows:


Concepts

Employment represents the estimate of total wage and salary employment in an occupation across the industries in which it was reported. The OES survey form sent to an establishment contains between 50 and 225 SOC occupations selected on the basis of the industry classification and size class of the sampled establishments. To reduce paperwork and respondent burden, no survey form contains every SOC occupation. Thus, data for specific occupations are collected primarily from establishments within industries that are the predominant employers of labor in those occupations.

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, nonproduction bonuses, and tuition reimbursements.

The OES survey collects wage data in 12 intervals. Employers report the number of employees in an occupation per each wage range. The wage intervals used for the 1999 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 $17,659
Range C $8.50 to $10.74 $17,660 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 wage is the estimated total wages for an occupation divided by its weighted survey employment. With the exception of the upper open-ended wage interval, interval L ($70.00 and over), a mean wage value is calculated for each wage interval based on occupational wage data collected by the Office of Compensation and Working Conditions. The mean wage value for the upper open-ended wage interval is its lower bound (Winsorized mean). These interval mean wage values are then attributed to all workers reported in the interval. For each occupation, total weighted wages in each interval are summed across all intervals and divided by the occupation's weighted survey employment.

Annual wage: Many employees are paid at an hourly rate by their employers and may work less than or more 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" hours figure of 2,080 hours per year (52 weeks by 40 hours). Thus, the annual wage estimates may not represent the actual annual pay received by the employee if they work fewer than 2,080 hours per year. There are a small number of occupations in this release where only an annual wage figure is provided; the workers in these occupations are generally paid on an annual basis, and their annual wage has been directly calculated from the reported survey data.

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 rates are constructed by multiplying the hourly wage rate for the interval by the typical work year of 2,080 hours. In reporting, the respondent can reference either the hourly or the annual rate, but is instructed to report the hourly rate for part-time workers.

There are workers in some occupations who are paid based on an annual amount, but generally work less than the usual 2,080 hours per year. Since the survey does not collect the actual hours worked, the hourly rate cannot be calculated with a reasonable degree of confidence from the annual wages. For this reason, only the annual salary is reported 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.

Estimation methodology

The OES survey samples approximately 400,000 establishments each year and, over a 3-year period, contacts approximately 1.2 million establishments. Each single-year sample represents a one-third sample of both the certainty and non-certainty strata for the full 3-year sample plan. While estimates can be made from a single year of data, the OES survey has been designed to produce estimates using the full 3 years of data. The full 3-year sample allows the production of estimates at fine levels of geography, industry, and occupational detail, while estimates using any one year of data would be subject to a higher sampling error (due to the smaller sample size) and the limitations associated with having only 1/3 of the units from the certainty strata. 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 the certainty strata (that is, large employers with 250+ employment).

Starting with the 1997 estimates, the OES program has used the over- the-year fourth-quarter wage changes from the Bureau's Employment Cost Index to adjust prior year survey data before combining it with the current year 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— and this may not be the case. The Bureau has conducted research over the past several years on the accuracy of the ECI wage-updating method versus other modeling approaches. Current research results support the continued use of the ECI wage-updating methodology.

1999 OES survey estimates: Beginning in 1999 the OES survey began using an occupational coding structure based on OMB's Standard Occupational Classification System. For 374 occupations that were one-to-one matches or direct aggregations between the two coding systems, the 1999 OES survey wage estimates are developed from the full three years of OES survey data. Wages for fifteen occupations that are one-to-one matches but had significant employment in the new wage range for workers earning $70.00 per hour and above are estimated using the 1999 survey data only. The remaining occupational wage estimates are developed from the 1999 survey data alone, which covers approximately 400,000 establishments. The combined 1997, 1998, and 1999 data cover approximately 1.2 million sample units. Occupations where the wage is estimated using three years of data are foot noted in Table 1. The 1999 employment estimates for all occupations are developed using the 1999 data alone.

The 1999 estimates use the wage-updating methodology introduced in 1997, which uses the over- the-year fourth-quarter wage changes from the Bureau's Employment Cost Index to adjust prior years' data before combining them with data from the current year. In addition, the 1999 estimates use the estimation methodology introduced in 1997, which uses a "nearest neighbor" imputation approach for nonrespondents and applies employment benchmarks at a detailed MSA by 3-digit industry and broad size class level.

Another challenge in combining data has been the 1999 transition to a new SOC-based OES occupational coding system. 1997 and 1998 data were cross-walked to the new SOC based classification system. Although most of the old OES occupations can be cross-walked to a counterpart in the new system, many of the relations between the two coding systems are not one-to-one. Many old OES occupations are cross-walked to residual occupations, meaning that occupation is no longer surveyed as a detailed occupation. Likewise, there are occupations in the new system that were not surveyed in the old system and thus there is only one year's worth of data for those occupations. For more information about the SOC, please see the BLS website at http://www.bls.gov/soc/soc_home.htm.

Future research: The expanded OES survey is a relatively new program, and BLS has a number of research efforts underway. Some areas of future research are given below.

Sample design research—BLS is evaluating the feasibility of collecting all certainty units (that is, large employers of 250+) every year so that more accurate independent estimates from a single year of sample data can be produced. These estimates will not contain possible effects from the wage-updating procedure and can provide an independent measure of the accuracy of the updating procedure along with the ability to use these data directly for more aggregate levels of publication.
Collection methodology research—This includes research on alternative electronic collection reporting procedures for respondents.
Estimation methodology research—An important research effort over the next several years will be the evaluation of the current wage-updating methodology along with the identification of alternative modeling approaches that may produce improved overall accuracy.

Additional information

The 1999 OES national data by occupation will be available on the Internet (/oes/). Users also may access each occupation's definition and percentile wages. The 1999 OES data for States will be available on the BLS website in mid-January, with data for metropolitan statistical areas (MSAs) available some time thereafter.

In addition to the data provided on the Internet, industry staffing patterns at the 2- and 3-digit Standard Industrial Classification (SIC) levels will be available electronically beginning in January 2001. These data will include industry-specific occupational employment and wage data. BLS also plans to release a bulletin displaying 1999 occupational employment and wage data for selected industries and areas in the spring of 2001.

For additional information, contact the Office of Employment and Unemployment Statistics, Occupational Employment Statistics, Room 4840, 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.

1999 National Occupational Employment and Wage Estimates

1999 State Occupational Employment and Wage Estimates

1999 Metropolitan Area Occupational Employment and Wage Estimates

1999 National Industry-Specific Occupational Employment and Wage Estimates

List of Occupations in SOC Code Number Order

List of Occupations in Alphabetical Order

Last Modified Date: January 10, 2007

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