What are Expert Systems?

Expert systems are developed to imitate the knowledge and expertise of an expert in a particular field. For example:

  • tax and financial calculations
  • road scheduling for delivery of vehicles
  • strategy games (e.g. chess)
  • identification of plants, animals or chemical compounds
  • prospecting for oil, gas and minerals
  • diagnosing a person’s illness
  • diagnostics (e.g. finding faults on a circuit board, faults in a car engine, etc)

How to set up an expert system

  • Several experts in a given field are first interviewed.
  • This results in the collection of data from these experts.
  • To store this data, a knowledge base is first designed and created.
  • Rules base and interference engines are also designed and created.
  • An explanation system is also developed.
  • Input and Output screens and formats also known as user interface, are designed and developed.
  • The expert system is tested against known conditions and scenarios and is also checked to see whether it meets the original specification.
  • Experts are interviewed about the effective of this system before it is officially released.


  • They never forget to answer a question when determining the logic.
  • They provide consistent results and are not affected by emotional reasoning.
  • Expert systems reduce the time to solve a problem.
  • The potential of saving money is high since the need of hiring specialists is reduced (e.g., when carrying out oil exploration).
  • Allows parts of the world access to expertise which they normally may not be able to afford.
  • They indicate the probability of the given solution being acccurate or correct.


  • Needs considerable training of the operators to ensure that the system is used correctly.
  • The initial setup costs are generally very high.
  • They tend to lack common sense in some of the decision-making processes.
  • Errors in the knowledge base can lead to incorrect decisions being made.
  • Though lack of emotional reasoning is an advantage, it can also be a disadvantage in certain areas like medical diagnosis.

Using an expert system

Taking oil prospecting as a case, the process for using an expert system would be as given below:

  1. An interactive user screen appears (this is often multiple-choice questions or Yes/No responses).
  2. The system asks questions about geological profiles.
  3. The operator keys in the answers to the questions/geological profiles.
  4. The system then asks questions based on the previous response(s) just keyed in.
  5. The inference engine compares the answers to questions with the facts or data fed in earlier in the knowledge base using the rules base.
  6. The system returns with the probability of finding oil as an output.
  7. It would also indicate the probable depth of the deposits (which is usually as a percentage probability).
  8. The explanations system would also explain how the expert system arrived with its conclusions.
  9. It would then make predictions about geological deposits in the soil/rocks.
  10. Finally, it produces contour maps showing the concentration of minerals, rocks, oil, etc.

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