Earliest government-based efforts to classify occupations stretch back to the post-civil war era. Rapid industrialization spawned the creation of new occupations requiring more specialized skills than generally exhibited by workers in a largely agrarian society. Industrial engineers studied job tasks in great detail, with remarkable efficiencies obtained from improved methods, materials, processes and machinery to maximize productivity. Influx of emigrants from rural communities and foreign immigrants presented challenges for how to best utilize the skills of this burgeoning workforce in the context of manufacturing needs and the building out of the country’s core infrastructure.

Two world wars and the Great Depression triggered the need for new ways to match people with jobs/training programs. Rapid assessment of basic abilities of World War I draftees began with the Army Alpha and Beta Exams for standardized testing of General Intelligence. Job matching on the basis of a standardized set of common job titles that became known as The Dictionary of Occupational Titles ([DOT], US Department of Labor [DOL], 1939) emerged from the activities of the Works Projects Administration (WPA). In World War II, the General Aptitude Test Battery (GATB) was invaluable as a multi-dimensional assessment of core aptitudes to guide personnel selection and military training decisions. The GATB was refined specifically for the military and was introduced in 1968 as the Armed Services Vocational Aptitude Battery (ASVAB).

Government sponsored research established performance-based cut scores (minimum aptitude requirements) for various groups of occupations. These were known as the Occupational Aptitude Patterns (OAP) and were incorporated into the Third Edition of the DOT in 1965, along with training time, general educational development, interests, temperaments, physical demands, working conditions, work performed, and industry designations. The Data-People-Things (DPT) “hierarchy” was also first introduced in the 1965 DOT.

In 1956, the Social Security Administration (SSA) was charged with the task of awarding monetary benefits to the most vulnerable segment of society: workers who were impacted by severe disability with the passage of the Social Security Amendment. Because of legal challenges as to how SSA determined eligibility for the program in the early to mid-1960s, the agency sought an authoritative source to better determine an applicant’s capacity to perform his/her previous work, or any work in the national economy, vis-à-vis physical and mental functional limitations. With no significant body of disability research upon which to build, SSA began funding a special project by the DOL to collect greater detail about occupations, with specific attention to various physical demands at the occupation level of detail, rather than for an occupational group. The Handbook for Analyzing Jobs (DOL, 1972) was the foundation for this initial data collection effort, which resulted in the Fourth Edition of the DOT (DOL, 1977). The DOL chose to make all job titles gender neutral at this time as well. The coding system introduced in 1977 provided a unique 9-digit number, with the specific purpose in mind of automation of this large dataset of 12,099 occupational definitions.

The DOL published the Selected Characteristics of Occupations of the Dictionary of Occupational Titles (SCO-DOT) in printed form (DOL, 1977). This new set of data spawned a new, systematic approach to the process of analyzing a worker’s skills and determining what other occupations the worker could do, either by choice or by necessity (disability onset or displacement). The process became known as the VDARE process (Vocational Diagnosis and Assessment of Residual Employability) and was published by McCroskey, Wattenbarger, Field, and Sink (1977). The process is book- and paper-based, and is popularly known as “The Blue Sheet.” The full set of characteristics was printed commercially as The Classification of Jobs According to Worker Trait Factors (Field & Field, 1980). The blue sheet is now known as the Transferability of Work Skills Worksheet (Elliott & Fitzpatrick, 1992).

The DOL also released data tapes to interested software developers of all of the printed information and of other information that it had collected but not printed. These data tapes, plus the introduction of the first generation of personal computers triggered the development of many computer-based vocational guidance and job matching systems, beginning about 1980. In 1982, the data was also available online (13 years prior to the 1995 explosion of public Internet access).

Several minor supplements to the DOT occurred in 1982 and 1986. The most recent edition of the DOT, Revised Fourth Edition was in 1991. This last revision subdivided the physical demand factors into discrete elements (e.g., separate ratings were released for Reaching, Handling, Fingering, and Feeling rather than treating all four as one factor as in the 1977 edition). This level of break-out helps SSA better adjudicate complex disability claims, particularly when manipulative/dexterity issues are involved.

In 1993, the DOL commissioned the Advisory Panel on the DOT (APDOT). The conclusions of this panel were to build a new occupational classification that was not as elaborate as the DOT to meet the needs of a changing economy and of 95% of its workforce clientele – people without disabilities. Starting with the DOT as its foundation, the DOL aggregated the 12,761 unique definitions in the DOT to about 1,100 distinct occupational groups. The DOL also developed a completely different and broader rating system for occupational elements and the importance of each those elements for every new occupational definition. This newest system is called the Occupational Information Network (O*NET) and breaks from the traditional book published format to now strictly a web-based resource. The data is regularly updated, primarily by job incumbent survey responses. The total number of defined occupations shrank since 1998 due to the Office of Management and Budget (OMB) requiring all Federal agencies to align occupational data along with the Standard Occupational Classification (SOC) that had a reduced number of occupations in its taxonomy. While the O*NET largely uses the SOC, it does not collect data to all SOC taxonomic occupations and has over 100 added occupations beyond the SOC taxonomy. In turn, since the initial requirement by the OMB, the SOC committee of Federal agencies developing occupational data has likewise expanded its title taxonomy with each revision. Now there are 974 detailed civilian occupational definitions. The O*NET Content Model explains the overall structure of this electronic resource available at http://www.onetcenter.org/content.html

Beginning with O*NET, the DOL, the Census Bureau, and the Bureau of Labor Statistics (BLS) have released increasing amounts of detail about occupations and labor markets in electronic format. Much of this public information is scattered in various government web sites operated by the respective agencies.

In 2008, the SSA chartered the Occupational Information Development Advisory Panel (OIDAP) to examine SSA’s options for greater detail about occupations than is currently available in any occupational classification system. The OIDAP identified various aspects of the elements SSA may need based on extensive stakeholder input (see http://www.ssa.gov/oidap) leading to SSA’s effort to work with other Federal agencies to create occupational information to truly replace the DOT for the way it is used in disability adjudication using carefully-defined and measured criteria for various human and work factors.

In 2013, SSA entered into an agreement with the National Compensation Survey arm of the BLS to gather the kind of information that SSA needs for the physical, environmental, mental, cognitive, and educational aspects of the SOC/O*NET to create and maintain a current, survey-based Occupational Information System (OIS) that would fit with the adjudication needs of the SSA disability determination programs. After several years of development and testing, data collection for the Occupational Requirements Survey (ORS) began in 2015. Some modifications were made to the cognitive elements in 2018, and data continues to be acquired from survey responses by small business owners and Human Resources (HR) managers. Data collection will continue until at least 2024, and it will likely continue thereafter to maintain a current body of information about these occupational factors. Complete details and initial data reporting is available at https://www.bls.gov/ors

To begin officially using the new OIS data will require substantial policy change at SSA. It is expected that this will begin to occur in or after 2020.