Multi-criteria decision making based on linguistic assessments

In our daily life, we are often faced with problems that require the selection of a solution from a given set of a finite number of alternatives in the presence of multiple, usually conflicting, criteria, so that the chosen alternative is a compromise option that meets all of these criteria. Most of real-world decision making problems involve uncertainty and imprecision in the estimates of performance ratings and criteria weights, i.e. we are unsure about our estimates. This lack of sureness is due to the fact that we do not know whether the data is reliable or not, or whether the situation may change or not. On the other hand, we don't often have precise information but unquantifiable information, incomplete information, non-obtainable information, or partial information. In a decision environment under uncertainty, it is too complex to reasonably describe the problem by conventional quantitative expressions; therefore, it is more adequate to express our judgments in a more qualitative form than a quantitative one. Thus, the use of a linguistic approach is necessary. The linguistic approach is an approximate technique which allows us to represent assessments as linguistic values by means of linguistic variables, defined as variables whose values are not numbers but words or sentences in a natural or artificial language. Defining linguistic variables, in a particular decision problem, is not as easy as it sounds, and diverse difficulties are presented, such as: (a) the cardinality of the linguistic term set used to express judgments; (b) the semantic of the linguistic term set; (c) the determinacy and consistency of linguistic terms; (d) the distribution of the linguistic terms; and (e) the combination of numerical and linguistic data. Another important aspect to consider is associated with how to aggregate assessments expressed in form of fuzzy numbers to rank alternatives, i.e., how to operate with fuzzy numbers. In order to make good decisions, it is important to make them in a systematic way becausewe're less likely to miss important factors. Given the importance of having a logical and systematic decision-making process, a linguistic multi-criteria decision making process is proposed and applied to the case of selecting a car to demonstrate the effectiveness of this methodology © 2012 Nova Science Publishers, Inc. All rights reserved.