Multiple criteria decision making - A case study of the Columbia River salmon recovery plan

A common problem faced by decision makers is choosing the best alternative from among many. Traditionally, such decisions in the public arena were made using benefit-cost analysis, which involves the conversion of all costs and benefits associated with a project into monetary terms. But public projects often have a variety of economic, ecological, social and political objectives, many of which cannot or perhaps should not be converted to monetary terms. In such projects decisions must be made based on multiple, even conflicting objectives. Multiple criteria decision making (MCDM) methods are widely used for such decisions. However, a common disadvantage among many such methods available in the literature is that they require input from a real decision maker. This paper presents the development and application of an expert system based on fuzzy set theory and IF-THEN rules. The system mimics a real decision maker. Along with two conventional MCDM methods the developed expert system was applied on a data set from the Columbia River Basin salmon recovery plan to assess its potential usefulness as a decision-making tool for natural resource projects. The results suggest that the fuzzy expert system is easy to develop and makes better decisions than the other two conventional MCDM methods used.