Present expert systems support only narrow domains of expertise. As the domain of application becomes broader, the number of alternative courses of action increases exponentially and effectiveness decreases exponentially. Though research is addressing this issue, practical expert systems are likely to be severely restricted in their domain for the next 5 years. Only limited knowledge-representation languages for data and relations are available. Because present expert systems need one domain expert in control to maintain consistency in the knowledge data base, they have only a single perspective on a problem.
Many expert systems are difficult to operate.