An Expert System for All

Computers are much cheaper than experts, so it might seem that an ES should be considered for any situation in which advice from a human expert might be helpful. However, many factors limit their use the two most crucial are cost and the difficulties of the extraction of knowledge. 

The principle cost of creating an ES is not the hardware on which the system runs or the software that is used to create it, but the cost of employing a human expert to create the system. Not only are human experts expensive creatures, but they also may be understandably reluctant to spend time developing a computerized copy of themselves, knowing that, the more perfectly they manage to distil their expertise into a computer system, the greater the chance that they will make themselves redundant. 

It may be fairly simple in principle to build an ES in areas such as analytical chemistry, in which most conditions and actions are clear-cut, but matters are not always so straightforward. A doctor uses a variety of tests and questions to determine what illness might be responsible for a patient s symptoms. While some of the data on which a doctor relies will 

---