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What is an expert system?

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November 2000
Eric Skjei

Definitions vary from the strangely tautological ("An expert system is a computer application that functions like an expert," says one online encyclopedia) to the exceptionally technical.

Expert systems, which are considered part of the field of artificial intelligence, generally attempt to capture the decison-making processes of human experts and represent them in the form of inferential "if . . . then" statements along the lines of "If the light is green, then step on the gas."

Cerner’s Vanetta Wick offers this more detailed definition: "Our rule-based expert knowledge system allows, through the use of English-language statements in the case of Millennium [Cerner’s latest version of its suite of PC-based products], what we call parameters, entry points that allow users to specify their particular interest level or their particular database entry. These statements, put together, make up what we call a rule, an expert knowledge module that runs on the customer’s system. "The statements are templates that drive system functionality," adds Wick. "There are evoke templates, which start the rule, logic templates, which are what the software evaluates, and action templates, which represent what it’s going to do based on what it found."

"Action templates drive what can be done with our system," says Wick, adding that actions can include e-mail transmissions, interactive alerts, cancel orders, add orders, add comments, executing an ad hoc query language, running reports, printing, and more.

Expert systems have been developed for many professions. Medicine is rich with work in this area and much of it is available on the Web.

Eric Skjei