Multiple criteria screening of a large water policy subset selection problem

A new screening approach is applied to a large-scale multiple criteria wate r management problem to remove actions that cannot possibly be in the best subset. An inherent advantage of the approach is its ability to identify in ferior actions by examining them individually, rather than within subsets. In a case study involving the selection of actions to address high water le vels in the Great Lakes-St. Lawrence Basin, two statistical indicators, the mode and the mean, are used to aggregate the opinions of experts and repre sentatives of interest groups on the impacts of actions according to variou s criteria. Application of the screening approach shows that some of the pr oposed actions can be removed as they can never be in the optimal subset, t hereby reducing the size of the problem.