Conflicts and coalitions

In a conflict situation, two or more decision-makers (DMs) are in dispute over some issue or resource. Initially, each disputant in the conflict will usually try to further its own goals, in a non-cooperative fashion.

However, a participant or a DM will often ponder the question of whether they could do even better by forming a coalition with one or more of the other DMs, in order to obtain mutual benefits for all coalition members. This sort of coalition formation is a naturally occurring sociological phenomenon which frequently gives rise to group decision and negotiation.

Now, Takehiro Inohara with the Department of Value and Decision Science in Tokyo Institute of Technology and Keith W. Hipel with the Department of Systems Design Engineering in University of Waterloo have jointly presented formal procedures for modeling and analyzing coalition formation. They have also demonstrated how their coalition analysis techniques can be conveniently employed in practice by applying them to a groundwater contamination dispute that took place in the town of Elmira, Ontario, Canada (see Figure).

The researchers made use of the so-called ‘Graph Model for Conflict Resolution’. The model allowed them to develop a novel approach to coalition analysis because of its inherent flexibility for systematically investigating real world conflict.

What’s more, the researchers defined new stability concepts for coalitions that take into account improvements of individual DMs, joint improvements of coalitions, sanctioning by single decision makers, and joint sanctions by coalitions. The work represents a significant extension to coalition analysis within the Graph Model paradigm.

As demonstrated by the practical application to Elmira, the coalition methodology can be readily applied to a real-world dispute consisting of two or more DMs. In practice, this means that an analyst is now in a better position to provide strategic guidance to a client as to when and how the client should or should not cooperate with others to produce a win/win situation or individual strategic advantage.

• Authors: Takehiro Inohara and Keith W. Hipel
• Title of original paper: Coalition Analysis in the Graph Model for Conflict Resolution
• Journal, volume, pages and year: Systems Engineering 11(4), 343-359, 2008
• Digital Object Identifier (DOI): 10.1002/sys.20104
• Affiliations: Department of Value and Decision Science, Graduate School of Decision Science and Technology, Tokyo Institute of Technology (Inohara) and Department of Systems Design Engineering, University of Waterloo (Hipel)
• Department website: http://www.valdes.titech.ac.jp/English/index.php (Inohara)

Graph Model for the Elmira groundwater contamination conflict indicating how the formation of coalitions could benefit or hinder different parties. Directed graphs G_M (left), G_U (middle), and G_L (right) are displayed at the top and the ranking of states for M, U, and L at the bottom.