Copeland Method II; Manipulation, Monotonicity, and Paradoxes

An important issue for economics and the decision sciences is to understand why allocation and decision procedures are plagued by manipulative and paradoxical behavior once there are n>3 or n=3 alternatives. Valuable insight is obtained by exploiting the relative simplicity of the widely used Copeland method (CM). By use of a geometric approach, we characterize all CM manipulation, monotonicity, consistency, and involvement properties while identifying which profiles are susceptible to these difficulties. For instance, we show that for n=3 candidates that the CM reduces the negative aspects of the Gibbard-Satterthwaite theorem.