The SIMUS Method

This chapter aims at explaining the SIMUS method, trying to show without formulas how it works. Its purpose is to illustrate the DM about its principles and characteristics for him or her to understand and apply it without going into complex mathematical demonstrations. That is, one thing is to understand a method, to know how to use it, and to know how to get the most from it, and another is to be knowledgeable about its mathematical intricacies. SIMUS is a hybrid method based on linear programming, weighted sum, and outranking methods. If the reader is interested or perhaps rather curious about how LP works, in the Appendix there is a detailed and accessible explanation. Since SIMUS is also grounded on the two abovementioned techniques it produces two results but with the same ranking. It is the equivalent of solving a problem with two distinctive methods and getting coincident rankings. Naturally, it does not mean that SIMUS delivers the “true” solution, if it exists, but these two similar outputs offer a good deal of reliability. Although SIMUS is a heuristic method, the compromising solution obtained is based on the Pareto efficient matrix. An application example illustrates how to load the data into the SIMUS software and shows its operation. The chapter continues explaining how to incorporate specific and real-world issues in the model and ends examining why both LP and SIMUS do not produce rank reversal.