A doubly extended TOPSIS method for group decision making based on ordered fuzzy numbers

Abstract

Multiple Attribute Decision Making methods have become very popular in recent years and are frequently applied in many real-life situations. The increasing complexity of the analysed decision problems makes it less feasible to consider all the relevant aspects of the problem by a single decision maker. As a result, many real-life problems are discussed by a group of decision makers. In such a group each decision maker can specialize in a different field and has his/her own unique characteristics, such as knowledge, skills, experience, personality, etc. This implies that each decision maker should have a different degree of influence on the final result, i.e., the ranking of alternatives. This means that the weights of decision makers should differ. The aim of this paper is to extend the TOPSIS method to group decision making, using ordered fuzzy numbers. The proposed approach uses TOPSIS twice. The first time it is used to determine the weights of decision makers which are then used to calculate the aggregated decision matrix for all the group decision matrices provided by the decision makers. Based on this aggregated matrix, the extended TOPSIS is used again, to rank the alternatives and to select the best one. A numerical example illustrates the proposed approach.