In MCDA, a set of alternative solutions for solving a given problem are evaluated and compared according to a range of criteria such as costs, benefits, environmental effects, and social impacts. Researchers in the Conflict Analysis Group have designed formal methods for taking interdependence among alternatives into account when a final resolution may consist of a combination of alternatives, such as when a regional government selects a mixture of groundwater, lake water and conservation alternatives for satisfying future water demands. They have developed different kinds of classification techniques to handle the elimination of inferior solutions, sorting of alternatives into groups ranked according to preference, and placing alternatives into nominal categories. With respect to sorting, a case-based distance approach and a data envelopment analysis technique have been mathematically defined and applied to case studies. Recently, they have proposed special MCDA methods for use in group decision making and negotiation. In fact, they have been working on problems in decision making under uncertainty and risk analysis through the introduction of fuzzy set theory into MCDA starting in the mid-1970s and information-gap modeling. These and other related methods have been applied to societal decision problems in water supply planning, varying water levels in the Great Lakes, electrical generation, third world infrastructure redevelopment, inventory management and business.