A Method for Decision Making Based on Generalized Aggregation Operators Jos´ e M. Merig ´ o, ∗ Anna M. Gil-Lafuente † Department of Business Administration, University of Barcelona 08034, Barcelona, Spain A new method for decision making based on generalized aggregation operators is presented. We use a concept that it is known in the literature as the index of maximum and minimum level (IMAM). This index uses distance measures and other techniques that are very useful for decision making. In this paper, it is suggested a generalization by using generalized and quasi-arithmetic means. As a result, it is obtained the generalized and quasi-arithmetic weighted IMAM (GWIMAM and quasi-WIMAM) and the generalized ordered weighted averaging IMAM (GOWAIMAM) and the quasi-OWAIMAM operator. The main advantage is that it provides a parameterized family of aggregation operators that includes a wide range of special cases such as the generalized IMAM and the OWAIMAM. Thus, the decision maker may take decisions according to his degree of optimism and considering ideals in the decision process. We also develop an application of the new approach in a decision-making problem regarding product selection. C  2013 Wiley Periodicals, Inc. 1. INTRODUCTION The index of the maximum and minimum (IMAM) level 1 is a very useful technique in decision making that provides similar results to the Hamming distance, but with some differences that make it more complete. It includes the Hamming distance and the adequacy coefficient 2 in the same formulation. Since its appearance, it has been used in a wide range of applications such as fuzzy set theory, business decisions, and multicriteria decision making. 3, 4 Note that in the literature, there are a wide range of other decision-making methods, refer, e.g., to Refs. 1–19. A very common aggregation method is the ordered weighted averaging (OWA) operator. 20 It provides a parameterized family of aggregation operators, which in- cludes the maximum, the minimum, and the average, as special cases. The OWA operator has been studied by various authors. 21–40 An interesting generalization of the OWA operator is the generalized OWA (GOWA) operator, 26, 35 which uses ∗ Author to whom all correspondence should be addressed: e-mail: jmerigo@ub.edu. † e-mail: amgil@ub.edu. INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, VOL. 28, 453–473 (2013) C  2013 Wiley Periodicals, Inc. View this article online at wileyonlinelibrary.com. • DOI 10.1002/int.21585