scholarly journals Incentives to Cultivate Favored Minorities Under Alternative Electoral Systems

1993 ◽  
Vol 87 (4) ◽  
pp. 856-869 ◽  
Author(s):  
Roger B. Myerson
Keyword(s):  
Simple Model ◽  
Small Groups ◽  
Electoral Systems ◽  
Scoring Rules ◽  
Game Model ◽  
Approval Voting ◽  
Voting Rules ◽  
Single Transferable Vote ◽  
Sincere Voting ◽  
Multicandidate Elections

A simple model is used to compare, under different electoral systems, the incentives for candidates to create inequalities among otherwise homogeneous voters, by making campaign promises that favor small groups, rather than appealing equally to all voters. In this game model, each candidate generates offers for voters independently out of a distribution that is chosen by the candidate, subject only to the constraints that offers must be nonnegative and have mean 1. Symmetric equilibria with sincere voting are analyzed for two-candidate elections and for multicandidate elections under rank-scoring rules, approval voting, and single transferable vote. Voting rules that can guarantee representation for minorities in multiseat elections generate, in this model, the most severely unequal campaign promises.

scholarly journals Characterising scoring rules by their solution in iteratively undominated strategies

2021 ◽  
Author(s):  
Christian Basteck
Keyword(s):  
Monotonicity Property ◽  
Scoring Rules ◽  
The Other ◽  
Approval Voting ◽  
Property A ◽  
Borda Rule ◽  
Scoring Rule ◽  
Direct Mechanism ◽  
Social Choice Correspondence ◽  
Choice Correspondence

AbstractWe characterize voting procedures according to the social choice correspondence they implement when voters cast ballots strategically, applying iteratively undominated strategies. In elections with three candidates, the Borda Rule is the unique positional scoring rule that satisfies unanimity (U) (i.e., elects a candidate whenever it is unanimously preferred) and is majoritarian after eliminating a worst candidate (MEW)(i.e., if there is a unanimously disliked candidate, the majority-preferred among the other two is elected). In a larger class of rules, Approval Voting is characterized by a single axiom that implies both U and MEW but is weaker than Condorcet-consistency (CON)—it is the only direct mechanism scoring rule that is majoritarian after eliminating a Pareto-dominated candidate (MEPD)(i.e., if there is a Pareto-dominated candidate, the majority-preferred among the other two is elected); among all finite scoring rules that satisfy MEPD, Approval Voting is the most decisive. However, it fails a desirable monotonicity property: a candidate that is elected for some preference profile, may lose the election once she gains further in popularity. In contrast, the Borda Rule is the unique direct mechanism scoring rule that satisfies U, MEW and monotonicity (MON). There exists no direct mechanism scoring rule that satisfies both MEPD and MON and no finite scoring rule satisfying CON.

Computer simulations of voting systems

2000 ◽  
Vol 03 (01n04) ◽  
pp. 181-194 ◽  
Author(s):  
Dominique Lepelley ◽  
Ahmed Louichi ◽  
Fabrice Valognes
Keyword(s):  
Monte Carlo ◽  
Computer Simulations ◽  
Monte Carlo Methods ◽  
Scoring Rules ◽  
Voting Systems ◽  
Voting Rules ◽  
Asymptotic Case ◽  
Majority Principle ◽  
Voting Procedures ◽  
Democratic Principles

All voting procedures are susceptible to give rise, if not to paradoxes, at least to violations of some democratic principles. In this paper, we evaluate and compare the propensity of various voting rules -belonging to the class of scoring rules- to satisfy two versions of the majority principle. We consider the asymptotic case where the numbers of voters tends to infinity and, for each rule, we study with the help of Monte Carlo methods how this propensity varies as a function of the number of candidates.

scholarly journals Preferences Single-Peaked on a Circle

2020 ◽  
Vol 68 ◽  
pp. 463-502 ◽  
Author(s):  
Dominik Peters ◽  
Martin Lackner
Keyword(s):  
Polynomial Time ◽  
Choice Theory ◽  
Social Choice Theory ◽  
Recognition Algorithm ◽  
Approval Voting ◽  
Voting Rules ◽  
One Dimensional ◽  
Facility Location Problems ◽  
Impossibility Results ◽  
Fast Recognition

We introduce the domain of preferences that are single-peaked on a circle, which is a generalization of the well-studied single-peaked domain. This preference restriction is useful, e.g., for scheduling decisions, certain facility location problems, and for one-dimensional decisions in the presence of extremist preferences. We give a fast recognition algorithm of this domain, provide a characterisation by finitely many forbidden subprofiles, and show that many popular single- and multi-winner voting rules are polynomial-time computable on this domain. In particular, we prove that Proportional Approval Voting can be computed in polynomial time for profiles that are single-peaked on a circle. In contrast, Kemeny's rule remains hard to evaluate, and several impossibility results from social choice theory can be proved using only profiles in this domain.

scholarly journals Approval voting and scoring rules with common values

2016 ◽  
Vol 166 ◽  
pp. 304-310 ◽  
Author(s):  
David S. Ahn ◽  
Santiago Oliveros
Keyword(s):  
Scoring Rules ◽  
Approval Voting ◽  
Common Values

Strategic Voting Versus Sincere Voting

2019 ◽  
Author(s):  
Damien Bol ◽  
Tom Verthé
Keyword(s):  
Electoral Systems ◽  
Strategic Voting ◽  
Proportional Representation ◽  
The Political ◽  
Political Class ◽  
Electoral Outcome ◽  
Representation Systems ◽  
The Government ◽  
Sincere Voting

People do not always vote for the party that they like the most. Sometimes, they choose to vote for another one because they want to maximize their influence on the outcome of the election. This behavior driven by strategic considerations is often labeled as “strategic voting.” It is opposed to “sincere voting,” which refers to the act of voting for one’s favorite party. Strategic voting can take different forms. It can consist in deserting a small party for a bigger one that has more chances of forming the government, or to the contrary, deserting a big party for a smaller one in order to send a signal to the political class. More importantly the strategies employed by voters differ across electoral systems. The presence of frequent government coalitions in proportional representation systems gives different opportunities, or ways, for people to influence the electoral outcome with their vote. In total, the literature identifies four main forms of strategic voting. Some of them are specific to some electoral systems; others apply to all.

Alternatywne ordynacje wyborcze. Przykład Australii i Irlandii

2016 ◽  
Vol 14 (3) ◽  
pp. 193-207
Author(s):  
Michał Urbańczyk
Keyword(s):  
Liberal Democracy ◽  
Electoral Systems ◽  
Common Type ◽  
Representative Democracy ◽  
Single Transferable Vote ◽  
Proper Functioning ◽  
Voting System

The essence of democracy is the rule of the sovereign, that is the nation, today understood as all of the state’s citizens. At present, the most common type of governance is representative democracy, exercised by representatives elected from the citizens themselves. Therefore, for the proper functioning of liberal democracy it is difficult to find a more important issue than the procedure for the election of those who govern us. The article presents two alternative electoral systems: an alternative voting system (AV) and the system of Single Transferable Vote (STV).

POPULAR SPANNING TREES

2013 ◽  
Vol 24 (05) ◽  
pp. 655-677 ◽  
Author(s):  
ANDREAS DARMANN
Keyword(s):  
Spanning Tree ◽  
Spanning Trees ◽  
Choice Theory ◽  
Social Choice Theory ◽  
Scoring Functions ◽  
Approval Voting ◽  
Voting Rules ◽  
Sharp Separation ◽  
Polynomially Solvable

Combinatorial Optimization is combined with Social Choice Theory when the goal is to decide on the quality of a spanning tree of an undirected graph. Given individual preferences over the edges of the graph, spanning trees are compared by means of a Condorcet criterion. The comparisons are based on scoring functions used in classic voting rules such as approval voting and Borda voting. In this work, we investigate the computational complexity involved in deciding on the quality of a spanning tree with respect to the different voting rules adapted. In particular, we draw the sharp separation line between polynomially solvable and computationally intractable instances.

scholarly journals Committee Scoring Rules: A Call to Arms

2017 ◽  
Author(s):  
Piotr Faliszewski
Keyword(s):  
Scoring Rules ◽  
Voting Rules

Committee scoring rules are a class of voting rules used to select sets of candidates based on the preferences of the voters. The goal of this paper is to present this class and to invite researchers to study its properties (computational and axiomatic alike).

scholarly journals Convergence of Iterative Scoring Rules

2016 ◽  
Vol 57 ◽  
pp. 573-591 ◽  
Author(s):  
Omer Lev ◽  
Jeffrey S. Rosenschein
Keyword(s):  
Linear Order ◽  
Scoring Rules ◽  
Voting Systems ◽  
Choice Functions ◽  
Stable States ◽  
Voting Rules ◽  
Voting Rule ◽  
Social Choice Functions ◽  
Breaking Mechanism ◽  
Iterative Voting

In multiagent systems, social choice functions can help aggregate the distinct preferences that agents have over alternatives, enabling them to settle on a single choice. Despite the basic manipulability of all reasonable voting systems, it would still be desirable to find ways to reach plausible outcomes, which are stable states, i.e., a situation where no agent would wish to change its vote. One possibility is an iterative process in which, after everyone initially votes, participants may change their votes, one voter at a time. This technique, explored in previous work, converges to a Nash equilibrium when Plurality voting is used, along with a tie-breaking rule that chooses a winner according to a linear order of preferences over candidates. In this paper, we both consider limitations of the iterative voting method, as well as expanding upon it. We demonstrate the significance of tie-breaking rules, showing that no iterative scoring rule converges for all tie-breaking. However, using a restricted tie-breaking rule (such as the linear order rule used in previous work) does not by itself ensure convergence. We prove that in addition to plurality, the veto voting rule converges as well using a linear order tie-breaking rule. However, we show that these two voting rules are the only scoring rules that converge, regardless of tie-breaking mechanism.

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