We allow departures from IIA in Arrow’s framework. Our measure of the extent of a departure is the amount of information needed to socially order a pair of alternatives. We also propose a measure of the scope of an individual’s power. The scope of at least one individual’s power increases...

There exist social choice rules for which every manipulation benefits everyone. This paper constructs a large variety of rules with this property and provides two characterizations of such rules. Copyright Springer-Verlag Berlin Heidelberg 2014

We identify the maximal number of people who are harmed when a social choice rule is manipulated. If there are n individuals, then for any <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$$k$$</EquationSource> </InlineEquation> greater than 0 and less than n, there is a neutral rule for which the maximal number is <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$$k$$</EquationSource> </InlineEquation>, and there is an anonymous rule for which the maximum...</equationsource></inlineequation></equationsource></inlineequation>

We investigate the implications of relaxing Arrow's independence of irrelevant alternatives axiom while retaining transitivity and the Pareto condition. Even a small relaxation opens a floodgate of possibilities for nondictatorial and efficient social choice.

Assuming an odd number of voters, E. S. Maskin recently provided a characterization of majority rule based on full transitivity. This paper characterizes majority rule with a set of axioms that includes two of Maskin's, dispenses with another, and contains weak versions of his other two axioms....

A feasible alternative x is a strong Condorcet winner if for every other feasible alternative y there is some majority coalition that prefers x to y. Let <InlineEquation ID="Equ1"> <EquationSource Format="TEX"><![CDATA[${\cal L}_{C}$]]></EquationSource> </InlineEquation> (resp., <InlineEquation ID="Equ2"> <EquationSource Format="TEX"><![CDATA[$\wp_{C})$]]></EquationSource> </InlineEquation> denote the set of all profiles of linear (resp., merely asymmetric) individual preference relations for which a strong Condorcet...</equationsource></inlineequation></equationsource></inlineequation>