414 research outputs found
And the loser is... Plurality Voting
This paper reports on a vote for choosing the best voting rules that was organized among the participants of the Voting Procedures workshop in July, 2010. Among 18 voting rules, Approval Voting won the contest, and Plurality Voting received no support at all.
The Myth of the Condorcet Winner
There is consensus among legal scholars that, when choosing among multiple alternatives, the Condorcet winner, should it exist, is the preferred option. In this essay I will refute that claim, both normatively and positively. In addition, I will suggest that a different approach, based in behavioral economics, might be a more productive way to model the choices that legislatures make among multiple alternatives
Models of Political Economy
Models of Political Economy will introduce students to the basic methodology of political economics. It covers all core theories as well as new developments including: decision theory game theory mechanism design games of asymmetric information. Hannu Nurmi's text will prove to be invaluable to all students who wish to understand this increasingly technical field
And the loser is... Plurality Voting
This paper reports on a vote for choosing the best voting rules that was organized among the participants of the Voting Procedures workshop in July, 2010. Among 18 voting rules, Approval Voting won the contest, and Plurality Voting received no support at all
The Strong Maximum Circulation Algorithm: A New Method for Aggregating Preference Rankings
We present a new optimization-based method for aggregating preferences in
settings where each decision maker, or voter, expresses preferences over pairs
of alternatives. The challenge is to come up with a ranking that agrees as much
as possible with the votes cast in cases when some of the votes conflict. Only
a collection of votes that contains no cycles is non-conflicting and can induce
a partial order over alternatives. Our approach is motivated by the observation
that a collection of votes that form a cycle can be treated as ties. The method
is then to remove unions of cycles of votes, or circulations, from the vote
graph and determine aggregate preferences from the remainder.
We introduce the strong maximum circulation which is formed by a union of
cycles, the removal of which guarantees a unique outcome in terms of the
induced partial order. Furthermore, it contains all the aggregate preferences
remaining following the elimination of any maximum circulation. In contrast,
the well-known, optimization-based, Kemeny method has non-unique output and can
return multiple, conflicting rankings for the same input. In addition, Kemeny's
method requires solving an NP-hard problem, whereas our algorithm is efficient,
based on network flow techniques, and runs in strongly polynomial time,
independent of the number of votes.
We address the construction of a ranking from the partial order and show that
rankings based on a convex relaxation of Kemeny's model are consistent with our
partial order. We then study the properties of removing a maximal circulation
versus a maximum circulation and establish that, while maximal circulations
will in general identify a larger number of aggregate preferences, the partial
orders induced by the removal of different maximal circulations are not unique
and may be conflicting. Moreover, finding a minimum maximal circulation is an
NP-hard problem.Comment: 22 pages, 4 figure
Computational Aspects of Multi-Winner Approval Voting
We study computational aspects of three prominent voting rules that use
approval ballots to elect multiple winners. These rules are satisfaction
approval voting, proportional approval voting, and reweighted approval voting.
We first show that computing the winner for proportional approval voting is
NP-hard, closing a long standing open problem. As none of the rules are
strategyproof, even for dichotomous preferences, we study various strategic
aspects of the rules. In particular, we examine the computational complexity of
computing a best response for both a single agent and a group of agents. In
many settings, we show that it is NP-hard for an agent or agents to compute how
best to vote given a fixed set of approval ballots from the other agents
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