Spoiler Susceptibility in Party Elections

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Boratyn, Daria, Słomczyński, Wojciech, Stolicki, Dariusz, Szufa, Stanisław
Format: Preprint
Publié: 2022
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866917048387371008
author Boratyn, Daria
Słomczyński, Wojciech
Stolicki, Dariusz
Szufa, Stanisław
author_facet Boratyn, Daria
Słomczyński, Wojciech
Stolicki, Dariusz
Szufa, Stanisław
contents An electoral spoiler is usually defined as a losing candidate whose removal would affect the outcome by changing the winner. So far, spoiler effects have been analyzed primarily for single-winner electoral systems. We consider this subject in the context of party elections, where there is no longer a sharp distinction between winners and losers. Hence, we propose a more general definition, under which a party is a spoiler if their elimination causes any other party's share in the outcome to decrease. We characterize spoiler-proof electoral allocation rules for zero-sum voting methods. In particular, we prove that for seats-votes functions only identity is spoiler-proof. However, even if spoilers are unavoidable under common electoral rules, their expected impact can vary depending on the rule. Hence, we introduce a measure of spoilership, which allows us to experimentally compare a number of multiwinner social choice rules according to their spoiler susceptibility. Since the probabilistic models used in COMSOC have been developed for nonparty elections, we extend them to generate multidistrict party elections.
format Preprint
id arxiv_https___arxiv_org_abs_2202_05115
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Spoiler Susceptibility in Party Elections
Boratyn, Daria
Słomczyński, Wojciech
Stolicki, Dariusz
Szufa, Stanisław
Computer Science and Game Theory
91B12 (Primary), 91B14
J.4
An electoral spoiler is usually defined as a losing candidate whose removal would affect the outcome by changing the winner. So far, spoiler effects have been analyzed primarily for single-winner electoral systems. We consider this subject in the context of party elections, where there is no longer a sharp distinction between winners and losers. Hence, we propose a more general definition, under which a party is a spoiler if their elimination causes any other party's share in the outcome to decrease. We characterize spoiler-proof electoral allocation rules for zero-sum voting methods. In particular, we prove that for seats-votes functions only identity is spoiler-proof. However, even if spoilers are unavoidable under common electoral rules, their expected impact can vary depending on the rule. Hence, we introduce a measure of spoilership, which allows us to experimentally compare a number of multiwinner social choice rules according to their spoiler susceptibility. Since the probabilistic models used in COMSOC have been developed for nonparty elections, we extend them to generate multidistrict party elections.
title Spoiler Susceptibility in Party Elections
topic Computer Science and Game Theory
91B12 (Primary), 91B14
J.4
url https://arxiv.org/abs/2202.05115