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NOTE: This page is archived for historical purposes and is no longer being maintained or updated.

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NOW Available

Newer web-based Industry and Occupation (I&O) coding tool: NIOSH Industry & Occupation Computerized Coding System (NIOCCS)

1.1 What is Industry and Occupation Coding?

By manipulating records on large numbers of individuals, researchers can learn whether individuals with certain characteristics are unusually likely to have other characteristics. In an example that is particularly relevant to the SOIC System, researchers can learn, by looking at a large number of cases, whether people who work in particular occupations and industries are unusually likely to become sick, injured, or die of particular causes. The number of possible occupations and industries that may be reported on death certificates and other records, however, is vast. The 1990 Alphabetical Index of Industries and Occupations, U.S. Bureau of the Census, lists about 21,000 industry titles and 30,000 occupation titles. However, there is no guarantee that persons filling out death certificates and other health records will use the titles included in the Alphabetical Index. In fact, an enormous variety of titles may show up in these records.

To make this vast range of possible titles manageable, researchers rely on industry and occupation coders (I&O coders) to classify the "literals"-that is, the actual titles found on death certificates and other records-into a limited number of categories.

I&O coding is a labor intensive, error prone task. Experienced coders may disagree at times over which code to assign to a particular literal. Coders must often contend with literals that are written by persons with no training in how to describe industries and occupations. In some cases the industry and occupation fields are switched. Company names may be used instead of actual industries. Literals can be misspelled or even illegible.

To make the job of the I&O coder easier, and to conserve the effort of skilled personnel, NIOSH commissioned the SOIC System-a software program to automate, as much as possible, the assignment of industry and occupation codes. Because I&O coding can be a difficult task even for human beings, it follows that the SOIC System is not capable of assigning correct codes to all literals. By coding most cases, however, the SOIC System can allow I&O coders to concentrate their efforts on a relatively small number of cases. The SOIC System uses a variety of methods for determining codes, including a number of relatively advanced techniques borrowed from the field of artificial intelligence. For additional information about industry and occupation coding, view the Industry and Occupation Coding Support page.