Hybrid Constructed Wetland Selection as a Group Decision-Making Problem

This paper proposes a framework based on the group analytic hierarchy process for identifying most desirable technologies for constructed wetland segmentation. A method is defined how to select decision makers whose evaluations should be included into the group decision by calculating different consistency and statistical conformity measures, and their aggregation into the new metrics. The consistency ratio, the total Euclidean distance, and the Spearman’s rank correlation coefficient are used to create the three two-dimensional metrics and the one three-dimensional metric to determine the distances of the decision makers from the reference points corresponding to full consistency and statistical conformity. The mapping the decision makers into the consistency/conformity scatter plots enables visualizing the outlier(s), that is, the decision makers who have different opinions about which technologies to apply in wetland segmentation than the decision makers on average. The scatter plots may guide the decision-making process towards grouping the decision makers into sub groups, thus heading towards consensus in both sub groups and global group. The approach is demonstrated on a numerical example application in which five decision makers are assessing six criteria of a constructed wetland segmentation selection.