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  • Selecting sample establishments (stage 1)
  • Probability sampling of occupations within sampled establishments (stage 2)
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Handbook of Methods Occupational Requirements Survey Design

Occupational Requirements Survey: Design

Occupational Requirements Survey (ORS) data are collected from a national probability sample selected in two stages:  (1) a probability sample of establishments and (2) a probability sample of occupations within sampled establishments. Probability samples are subject to sampling and nonsampling errors, which are discussed in the Calculation section.

Selecting sample establishments (stage 1)

In stage 1, the ORS uses a probability proportional to size (PPS) technique to select a sample of private industry and state and local government establishments from across the nation. The larger the establishment, the greater its chance of being selected. Establishments from all 50 states and the District of Columbia are eligible for selection. ORS stratifies by 23 major industry groups and ownership (private industry and state and local government). More detailed information on ORS sample design can be found in Occupational Requirements Survey Sample Design.

With some minor exceptions, an establishment is a single economic unit that engages in one, or predominantly one, type of economic activity. For private industries in the survey, the establishment usually is at a single physical location, such as a mine, a factory, an office, or a store, that produces goods or provides services. For private industry, if a sampled establishment is owned by a larger entity with many locations, only the employment and characteristics of the establishment selected for the sample are considered for the survey. For state and local governments, an establishment can include more than one physical location, such as a school district or a police department. Each establishment is assigned a six-digit industry code using the North American Industry Classification System (NAICS). When a single physical location encompasses two or more distinct economic activities, the industry code assigned is based on the establishment's principal product, or group of products, produced or distributed, or services rendered. When determining the principle product or service rendered, revenue generated or employment are used to determine the primary business activity and assign an industry code. 

The sampling frame, or universe, is the list of establishments from which the survey sample is selected. The ORS establishment sample is drawn from the Quarterly Census of Employment and Wages (QCEW). Because the sample of establishments used to collect ORS data is chosen ahead of time, establishment weights reflect employment at the time of sampling, not collection.

Industry classification of establishments. All federal statistical agencies currently use NAICS to classify survey establishments by industry. NAICS revises its industry classifications every 5 years to stay current with industrial organization in North America. In selecting new establishment samples, the ORS uses the most recent version of NAICS (2012) as one of the stratification variables.

Sample groups. The 2016 annual estimates are from a single sample of collected data. The ORS is an establishment-based survey, using a national sample design. To maximize the amount of publishable information, BLS combines data across three annual ORS samples. The number of publishable occupations and the level of occupational detail is expected to increase with the addition of each subsequent sample group until the full ORS sample size of up to 30,000 sampled establishments is reached. Because the ORS combines data across sample groups, there is a possibility that an establishment will be reselected in a subsequent sample. However, ORS data are not collected from the same establishment in more than one sample group. In this case, the data from the original interview with the establishment would be used.

Probability sampling of occupations within sampled establishments (stage 2)

The ORS collects data on workers who are employed by the sampled establishment. People working onsite at a surveyed establishment, but paid by a contractor, are not included in data collection from the establishment, unless the contractor is part of the sample. In that case, the ORS collects data on employees of the contractor who are working offsite at other establishments, as well as those working onsite. To be included in the ORS, employees in sampled occupations must receive payments (cash, check, or direct deposit payments) from the establishment for services performed and the establishment must pay the employer’s portion of Medicare taxes on those individuals’ wages.

The number of workers in an establishment includes workers on paid vacation or other types of leave; salaried of­ficers, executives, and staff members of incorporated firms; employees temporarily assigned to other units; and noncon­tract employees for whom the reporting unit is the perma­nent duty station, regardless of whether that unit issues their paychecks.

In stage 2, field economists use a four step process to select and classify jobs for which data are to be collected during the initial contact with the sampled establishment.

Step 1: Field economist receives the establishment’s complete list of employees and their job titles and performs the probability selection of occupations (PSO) technique. The field economist uses the PSO technique to randomly select the jobs for which data are to be collected. This process ensures that the probability of selecting a given job is proportional to the number of workers in the job at the establishment. The number of jobs selected for data collection is based on the establishment’s employment size, according to the following criteria:

Exceptions include state and local government units, for which up to 20 jobs may be selected.

Step 2: Field economists match employees working in the sampled jobs with an occupation. The sampled jobs are classified into occupations based on the workers’ actual job duties and responsibilities, not on their job titles or specific education. For example, an employee trained as an engineer, but working as a drafter, is reported as a drafter. An employee who performs the duties of two or more occupations is reported as working in the occupation that requires the highest level of skill or in the occupation in which the employee spends the most time if there is no measurable difference in skill requirements. Each occupation is designated by an eight-digit code in the Occupational Information Network’s (O*NET) detailed occupational taxonomy, referred to as O*NET-SOC 2010 occupations. This code is part of a hierarchical structure as shown in the following exhibit.

O*NET-SOC 2010 occupations are grouped under and include the Standard Occupational Classification (SOC) detailed occupations. SOC detailed occupations are grouped under broad occupations, broad occupations are part of a minor group, and minor groups are part of a major group. The example above shows the hierarchy of ‘architectural drafters’ and ‘civil drafters’ O*NET-SOC 2010 occupations.

The SOC designates 23 major groups and there are 1,110 O*NET-SOC 2010 occupations within these 23 groups. For the purposes of the ORS, occupations can fall into 22 major groups and 1,090 occupations; only the major group 23 (code 55-0000.00), military-specific occupations, is excluded.

Step 3: Identification of occupational attributes of the worker, such as full-time or part-time status, union or nonunion status, and whether the work is paid on a time or incentive basis. The field economist records specific attributes of the worker in the sampled job, for each selected occupation. Each such occupation must include only workers with the same attributes; for example, the occupation cannot include both full-time and part-time workers. For definitions of occupational attributes see the Concepts section.

Step 4: Field economists evaluate the job to determine the work level of its duties and responsibilities using a point-factor system of points based on the following factors:

• Knowledge
• Job controls and complexity
• Contacts
• Physical environment

Each factor consists of several points and a description. The duties and responsibilities of the job, along with consideration given to work performed and the skills, education, and training required for the job are evaluated. Points are then totaled to determine the overall work level for the job. Generally, the greater the impact, complexity, or difficulty of the factor, the higher the number of points assigned, and the higher the work level. As the following exhibit shows, there are some occupations that cannot be “leveled,” because for the following jobs points cannot be determined for all four factors, thus points are not assigned and a level cannot be determined.