There are certain criteria for making this decision. These criteria are formalized as rules. Over time a loan officer becomes familiar with the rules and no longer has to refer to the rule book every time a decision needs to be made. An expert system has these same rules in its knowledge base and can efficiently make the decision just as quickly and effectively as the expert. Such a system allows a not so experienced loan officer to make the same decision the expert would make and, as it always refers to the rule book, to make those decisions more consistently.
Similar applications exist in many other problem domains.
Business Insight is an expert system designed for a business application. This application allows management to see the relationships between different departments in the organization as well as outside the organization. One particularly useful feature was the ability to test the system. You can do this continuously until you achieve the results you would like, and you can view the criteria needed to achieve those results. Business Insight goes further, it not only gives insight into the marketing side of the business, but into the company's total business.