Reliability-based approach to multicriteria decision analysis for water resources

Analyses of water resource allocation problems can be undertaken using multicriteria decision analysis (MCDA), yet various sources of uncertainty exist in the application of MCDA methods, including the definition of criteria weights and the assignment of criteria performance values. Sensitivity analysis can be used to analyze the effects of these uncertainties on the ranking of alternatives; however, many existing methods have been found to have numerous limitations when applied to MCDA. In this paper, a reliability-based approach is proposed that enables the decision maker to examine the robustness of a solution, allowing a decision to be made with confidence that the alternative chosen is the best performing alternative under the range of probable circumstances. The proposed stochastic method involves defining the uncertainty in the input values using probability distributions, performing a reliability analysis by Monte Carlo simulation and undertaking a significance analysis using the Spearman rank correlation coefficient. The outcomes of the approach include a distribution of the total values of each alternative based upon the expected range of input parameter values. The benefits of the approach are illustrated by applying it to two water resources case studies.