Efficiency and Consistency in Group Decisions
The paper introduces a concept of “efficiency set" in the context of group decisions and analyses its properties. If the set contains a single element, then the Borda rule finds it. Otherwise, the group needs a value function to choose from the efficient alternatives. Two value functions, with considerations for the number of participants who are badly affected by the choice, have been discussed. It turns out that the consistency axiom of group choice imposes a constraint, on the form of the value function, with questionable normative significance.