Sensitivity Analysis by SIMUS: The IOSA Procedure

This chapter addresses a fundamental subject: sensitivity analysis. It is not only a checking procedure but also a tool that allows the DM to answer questions from stakeholders as well as a way to study different attitudes; without it a MCDM process is incomplete. The main reason for its use lies in the uncertainty of data, and therefore, a test must be performed to verify how a solution holds when certain parameters change. In this book, sensitivity analysis is performed in a different and novel way, compared as it is done nowadays because there are nonsubjective assumptions, and it is based on what is believed to be a more rational approach, by using economics principles such as criteria marginal values instead of subjective criteria weights. The advantage over the lack of effectiveness and transparency of the actual procedure is that it permits not only determining when a ranking changes – as is the information given by all methods – but also getting a quantitative measure on the effect of these changes. It also provides a graphic display of how the objective value increases or decreases according to increments or decrements in some criteria. Another advantage is that it allows analysis of how exogenous factors, related somehow with criteria, may affect the best selection in the future, during operation of the alternative selected. Due to this, it is possible to compute the value of diverse risks related to the potential changes of these exogenous factors.