• Overview
• Concepts
• Data sources
• Design
  • Selecting sample establishments (stage 1)
  • Probability sampling of occupations within sampled establishments (stage 2)
• Calculation
• Presentation
• History
• More Info

• Methods Home
• About
• Programs
• Glossary
search

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 (PSO) 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 the establishments by 23 major industry groups and ownership (private industry and state and local government) and the ORS program implicitly stratifies within each sampling cell for 24 geographic areas. The 24 geographic areas represent the 15 largest metropolitan areas and the 9 census divisions. More detailed information on ORS sample design can be found in the sample design portion of the Research section on the public ORS website.

Each sampled establishment has an assigned 6-digit industry code from 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 products, whether produced or distributed, or the principal services rendered by the establishment. When determining the principle product or service rendered, employment is used to determine the primary business activity and assign an industry code. When the primary activity cannot be determined by employment then it’s determined based on the revenue generated.

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) and units reporting to the Railroad Retirement Board.

Sample groups

To maximize the amount of publishable information, BLS combined data across three samples collected over a 3-year period to produce the 2018 estimates. The total sample included approximately 25,300 establishments and estimates represent about 140,800,000 civilian workers.

Probability sampling of occupations within sampled establishments (stage 2)

The ORS collects data about requirements of jobs from sampled establishments. In stage 2, field economists use a four-step process to select and classify jobs for which data are to be collected from the sampled establishment.

Step 1: Field economists receive the establishment’s complete list of employees and their job titles and perform the 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. (See Data sources section for more information.) The number of jobs selected for data collection is based on the establishment’s employment size, according to the following criteria:

Step 2: Field economists classify the sampled jobs 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. Field economists classify employees who perform the duties of two or more distinct occupations 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 sampled job is classified by the Standard Occupational Classification (SOC) system to the 6-digit level, and further designated by an 8-digit code in the Occupational Information Network’s (O*NET) detailed occupational taxonomy when available. These are referred to as O*NET-SOC 2010 occupations. This code is part of a hierarchical structure as shown in the following exhibit.

Exhibit 1. Hierarchical classification structure

The 1,110 O*NET-SOC 2010 occupations are grouped under and include the 840 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 designating military-specific occupations is excluded (code 55-0000.00 and detailed occupations within this major group).

Step 3: Identification of occupational attributes of the worker in the sampled job, 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 occupational attributes of the worker in the sampled job. 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. This is a 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. Field economists evaluate the duties and responsibilities of the job, taking into account work performed and the skills, education, and training required for the job. 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. Some occupations, such as those listed in the exhibit below, cannot be “leveled” because points cannot be determined for all four factors. Thus, a level cannot be determined.