Download or read book Multi Winner Voting with Approval Preferences written by Martin Lackner and published by Springer. This book was released on 2022-11-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: From fundamental concepts and results to recent advances in computational social choice, this open access book provides a thorough and in-depth look at multi-winner voting based on approval preferences. The main focus is on axiomatic analysis, algorithmic results and several applications that are relevant in artificial intelligence, computer science and elections of any kind. What is the best way to select a set of candidates for a shortlist, for an executive committee, or for product recommendations? Multi-winner voting is the process of selecting a fixed-size set of candidates based on the preferences expressed by the voters. A wide variety of decision processes in settings ranging from politics (parliamentary elections) to the design of modern computer applications (collaborative filtering, dynamic Q&A platforms, diversity in search results, etc.) share the problem of identifying a representative subset of alternatives. The study of multi-winner voting provides the principled analysis of this task. Approval-based committee voting rules (in short: ABC rules) are multi-winner voting rules particularly suitable for practical use. Their usability is founded on the straightforward form in which the voters can express preferences: voters simply have to differentiate between approved and disapproved candidates. Proposals for ABC rules are numerous, some dating back to the late 19th century while others have been introduced only very recently. This book explains and discusses these rules, highlighting their individual strengths and weaknesses. With the help of this book, the reader will be able to choose a suitable ABC voting rule in a principled fashion, participate in, and be up to date with the ongoing research on this topic.

Download or read book Satisfaction Approval Voting written by Fouad Sabry and published by One Billion Knowledgeable. This book was released on 2024-09-05 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Satisfaction Approval Voting" presents an innovative electoral system designed to improve voter satisfaction and representational outcomes. This book explores how Satisfaction Approval Voting (SAV) integrates approval voting principles with enhancements that optimize democratic processes. 1-Satisfaction Approval Voting-An introduction to SAV and its revolutionary approach to electoral satisfaction. 2-Approval Voting-A look at approval voting, allowing voters to support multiple candidates for fairness. 3-Proportional Representation-Explores proportional representation’s role in achieving equitable outcomes. 4-Score Voting-Discusses score voting, a system where voters assign scores to candidates. 5-Two-round System-Analyzes how the two-round system ensures broad candidate support. 6-Single Transferable Vote-Unpacks the single transferable vote system for proportional outcomes. 7-Strategic Voting-Covers strategic voting and its influence on electoral results. 8-Voting-Provides a comprehensive overview of voting principles and systems. 9-Electoral System-Analyzes the impact of different electoral systems on democracy. 10-Cardinal Voting-Explores how cardinal voting rates candidates, highlighting its strengths. 11-Multiple Non-Transferable Vote-Examines this system's role in specific electoral contexts. 12-Ranked Voting-Discusses ranked voting and its preference-based candidate ranking. 13-Proportional Approval Voting-Explores how this method combines approval voting with proportionality. 14-Sequential Proportional Approval Voting-Looks at a sequential approach to improve proportional outcomes. 15-Combined Approval Voting-Analyzes how this method integrates multiple voting systems. 16-STAR Voting-A breakdown of STAR (Score Then Automatic Runoff) voting and its benefits. 17-Social Utility Efficiency-Explores how voting systems can optimize social utility. 18-Justified Representation-Focuses on achieving fair representation in electoral processes. 19-Multiwinner Approval Voting-Covers how multiwinner approval voting represents diverse interests. 20-Multiwinner Voting-Discusses various multiwinner systems for balanced representation. 21-Multi-Issue Voting-Explores multi-issue voting for elections involving multiple topics. "Satisfaction Approval Voting" is more than a book—it's a valuable resource for anyone interested in democratic reform. Whether you're a professional, student, or enthusiast, this book offers powerful insights into how SAV can transform voting and representation. Dive in to explore the future of electoral reform.

Download or read book Approval Voting written by Fouad Sabry and published by One Billion Knowledgeable. This book was released on 2024-09-05 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: Approval Voting-Enhancing Democratic Representation in Political Science What is Approval Voting? This book explores approval voting systems and their impact on democratic representation, voter satisfaction, and efficiency. It offers a deep dive into the benefits and challenges of using this system in elections. Chapters Overview 1-Approval Voting-Introduction to the core concepts and principles of approval voting. 2-Score Voting-Compares score voting and its outcomes with approval voting. 3-Condorcet Method-Discusses the Condorcet method and its differences from approval voting. 4-Strategic Voting-Analyzes strategic voting and how approval voting interacts with it. 5-Borda Count-Reviews the Borda count system and its comparative advantages. 6-Condorcet Winner Criterion-Evaluates approval voting against the Condorcet winner criterion. 7-Condorcet Loser Criterion-Investigates how approval voting handles the Condorcet loser criterion. 8-Participation Criterion-Examines approval voting's impact on voter participation. 9-Comparison of Electoral Systems-A detailed comparison of approval voting with other systems. 10-Multiwinner Voting-Explores approval voting’s application in multiwinner elections. 11-Two-Round System-Compares the two-round system with approval voting. 12-Bucklin Voting-Introduction to Bucklin voting and its mechanisms. 13-Majority Criterion-Evaluates approval voting against the majority criterion. 14-Nanson’s Method-Analyzes Nanson’s method and its relevance to approval voting. 15-Later-No-Harm Criterion-Discusses this criterion and its role in voter behavior. 16-Independence of Clones Criterion-Explores the criterion’s importance in approval voting. 17-Instant-Runoff Voting-Compares instant-runoff voting with approval voting. 18-Cardinal Voting-Analyzes cardinal voting systems and voter satisfaction. 19-Ranked Voting-Compares ranked voting systems with approval voting. 20-Later-No-Help Criterion-Investigates this criterion in the context of approval voting. 21-STAR Voting-Introduction to STAR voting and its comparison to approval voting. Who is this book for? This book is invaluable for students, professionals, and enthusiasts seeking a comprehensive understanding of electoral systems, providing essential insights into the nuances of approval voting.

Download or read book Multiwinner Approval Voting written by Steven J. Brams and published by . This book was released on 2017 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: We extend approval voting so as to elect multiple candidates, who may be either individuals or members of a political party, in rough proportion to their approval in the electorate. We analyze two divisor methods of apportionment, first proposed by Jefferson and Webster, that iteratively depreciate the approval votes of voters who have one or more of their approved candidates already elected. We compare the usual sequential version of these methods with a nonsequential version, which is computationally complex but feasible for many elections. Whereas Webster apportionments tend to be more representative of the electorate than those of Jefferson, the latter, whose equally spaced vote thresholds for winning seats duplicate those of cumulative voting in 2-party elections, is even-handed or balanced.

Download or read book Handbook on Approval Voting written by Jean-François Laslier and published by Springer Science & Business Media. This book was released on 2010-06-25 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: With approval voting, voters can approve of as many candidates as they want, and the one approved by the most voters wins. This book surveys a wide variety of empirical and theoretical knowledge accumulated from years of studying this method of voting.

Download or read book Multi Winner Voting with Approval Preferences written by Martin Lackner and published by Springer Nature. This book was released on 2022-11-17 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: From fundamental concepts and results to recent advances in computational social choice, this open access book provides a thorough and in-depth look at multi-winner voting based on approval preferences. The main focus is on axiomatic analysis, algorithmic results and several applications that are relevant in artificial intelligence, computer science and elections of any kind. What is the best way to select a set of candidates for a shortlist, for an executive committee, or for product recommendations? Multi-winner voting is the process of selecting a fixed-size set of candidates based on the preferences expressed by the voters. A wide variety of decision processes in settings ranging from politics (parliamentary elections) to the design of modern computer applications (collaborative filtering, dynamic Q&A platforms, diversity in search results, etc.) share the problem of identifying a representative subset of alternatives. The study of multi-winner voting provides the principled analysis of this task. Approval-based committee voting rules (in short: ABC rules) are multi-winner voting rules particularly suitable for practical use. Their usability is founded on the straightforward form in which the voters can express preferences: voters simply have to differentiate between approved and disapproved candidates. Proposals for ABC rules are numerous, some dating back to the late 19th century while others have been introduced only very recently. This book explains and discusses these rules, highlighting their individual strengths and weaknesses. With the help of this book, the reader will be able to choose a suitable ABC voting rule in a principled fashion, participate in, and be up to date with the ongoing research on this topic.

Download or read book Score Then Automatic Runoff Voting written by Fouad Sabry and published by One Billion Knowledgeable. This book was released on 2024-09-05 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discover an innovative approach that reshapes our understanding of electoral systems. Score Then Automatic Runoff Voting explores a hybrid method combining the precision of score voting with the clarity of automatic runoffs. This book is crucial for those interested in the future of democratic representation and electoral integrity. You'll uncover the unique aspects of this system and its potential influence on election outcomes, voter satisfaction, and democracy. Here's a brief look inside: 1: STAR Voting-How STAR voting merges score voting with automatic runoff for more accurate election results. 2: Approval Voting-Understanding approval voting and its role in candidate evaluation based on voter acceptance. 3: Score Voting-Exploring score voting fundamentals and its advantage in capturing voter preferences. 4: Condorcet Method-Identifying the most preferred candidate through pairwise comparisons using the Condorcet method. 5: Copeland's Method-Learn how Copeland's method uses pairwise victories to determine the best candidate. 6: Monotonicity Criterion-Why increasing support for a candidate shouldn't harm their chances (monotonicity criterion). 7: Bucklin Voting-Multi-round Bucklin voting to find a majority winner. 8: Ranked Pairs-Facilitating ranking based on majority preferences using ranked pairs. 9: Condorcet Winner Criterion-The importance of selecting a candidate who wins in every head-to-head match. 10: Participation Criterion-Encouraging voter turnout through the participation criterion. 11: Majority Criterion-Ensuring broad support for the winning candidate via the majority criterion. 12: Mutual Majority Criterion-Favoring candidates with cross-sectional support under the mutual majority criterion. 13: Nanson's Method-Eliminating less popular candidates to find a consensus choice using Nanson's method. 14: Condorcet Loser Criterion-Ensuring a universally losing candidate isn’t elected. 15: Reversal Symmetry-Exploring fairness in electoral systems through reversal symmetry. 16: Kemeny–Young Method-Aggregating preferences for candidate ranking via the Kemeny–Young method. 17: Later-No-Harm Criterion-Ensuring lower rankings don’t harm candidates' chances (later-no-harm criterion). 18: Instant-Runoff Voting-Eliminating least popular candidates in rounds until a majority winner emerges. 19: Majority Judgment-Evaluating candidates through graded assessments using majority judgment. 20: Ranked Voting-How ranked voting systems impact voter choice and representation. 21: Comparison of Electoral Systems-Comparing strengths and weaknesses of various systems in different contexts. Score Then Automatic Runoff Voting offers a deep dive into the future of electoral innovation. By engaging with this guide, you'll enhance your understanding of voting methods and their democratic implications. Stay ahead in the evolving world of elections.

Download or read book The Excess Method written by Steven J. Brams and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In using approval voting to elect multiple winners to a committee or council, it is desirable that excess votes -- approvals beyond those that a candidate needs to win a seat -- not be wasted. The excess method does this by sequentially allocating excess votes to a voter's as-yet-unelected approved candidates, based on the Jefferson method of apportionment. It is monotonic -- approving of a candidate never hurts and may help him or her get elected -- computationally easy, and less manipulable than related methods. In parliamentary systems with party lists, the excess method is equivalent to the Jefferson method and thus ensures the approximate proportional representation of political parties. As a method for achieving proportional representation (PR) on a committee or council, we compare it to other PR methods proposed by Hare, Andrae, and Droop for preferential voting systems, and by Phragmén for approval voting. Because voters can vote for multiple candidates or parties, the excess method is likely to abet coalitions that cross ideological and party lines and to foster greater consensus in voting bodies.

Download or read book Electoral Systems written by Dan S. Felsenthal and published by Springer Science & Business Media. This book was released on 2012-01-03 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: Both theoretical and empirical aspects of single- and multi-winner voting procedures are presented in this collection of papers. Starting from a discussion of the underlying principles of democratic representation, the volume includes a description of a great variety of voting procedures. It lists and illustrates their susceptibility to the main voting paradoxes, assesses (under various models of voters' preferences) the probability of paradoxical outcomes, and discusses the relevance of the theoretical results to the choice of voting system.

Download or read book Trends in Computational Social Choice written by Ulle Endriss and published by Lulu.com. This book was released on 2017 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational social choice is concerned with the design and analysis of methods for collective decision making. It is a research area that is located at the interface of computer science and economics. The central question studied in computational social choice is that of how best to aggregate the individual points of view of several agents, so as to arrive at a reasonable compromise. Examples include tallying the votes cast in an election, aggregating the professional opinions of several experts, and finding a fair manner of dividing a set of resources amongst the members of a group -- Back cover.

Download or read book Algorithmic aspects of resource allocation and multiwinner voting theory and experiments written by Kaczmarczyk, Andrzej and published by Universitätsverlag der TU Berlin. This book was released on 2021-12-10 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is concerned with investigating elements of computational social choice in the light of real-world applications. We contribute to a better understanding of the areas of fair allocation and multiwinner voting. For both areas, inspired by real-world scenarios, we propose several new notions and extensions of existing models. Then, we analyze the complexity of answering the computational questions raised by the introduced concepts. To this end, we look through the lens of parameterized complexity. We identify different parameters which describe natural features specific to the computational problems we investigate. Exploiting the parameters, we successfully develop efficient algorithms for spe- cific cases of the studied problems. We complement our analysis by showing which parameters presumably cannot be utilized for seeking efficient algorithms. Thereby, we provide comprehensive pictures of the computational complexity of the studied problems. Specifically, we concentrate on four topics that we present below, grouped by our two areas of interest. For all but one topic, we present experimental studies based on implementations of newly developed algorithms. We first focus on fair allocation of indivisible resources. In this setting, we consider a collection of indivisible resources and a group of agents. Each agent reports its utility evaluation of every resource and the task is to “fairly” allocate the resources such that each resource is allocated to at most one agent. We concentrate on the two following issues regarding this scenario. The social context in fair allocation of indivisible resources. In many fair allocation settings, it is unlikely that every agent knows all other agents. For example, consider a scenario where the agents represent employees of a large corporation. It is highly unlikely that every employee knows every other employee. Motivated by such settings, we come up with a new model of graph envy-freeness by adapting the classical envy-freeness notion to account for social relations of agents modeled as social networks. We show that if the given social network of agents is simple (for example, if it is a directed acyclic graph), then indeed we can sometimes find fair allocations efficiently. However, we contrast tractability results with showing NP-hardness for several cases, including those in which the given social network has a constant degree. Fair allocations among few agents with bounded rationality. Bounded rationality is the idea that humans, due to cognitive limitations, tend to simplify problems that they face. One of its emanations is that human agents usually tend to report simple utilities over the resources that they want to allocate; for example, agents may categorize the available resources only into two groups of desirable and undesirable ones. Applying techniques for solving integer linear programs, we show that exploiting bounded rationality leads to efficient algorithms for finding envy-free and Pareto-efficient allocations, assuming a small number of agents. Further, we demonstrate that our result actually forms a framework that can be applied to a number of different fairness concepts like envy-freeness up to one good or envy-freeness up to any good. This way, we obtain efficient algorithms for a number of fair allocation problems (assuming few agents with bounded rationality). We also empirically show that our technique is applicable in practice. Further, we study multiwinner voting, where we are given a collection of voters and their preferences over a set of candidates. The outcome of a multiwinner voting rule is a group (or a set of groups in case of ties) of candidates that reflect the voters’ preferences best according to some objective. In this context, we investigate the following themes. The robustness of election outcomes. We study how robust outcomes of multiwinner elections are against possible mistakes made by voters. Assuming that each voter casts a ballot in a form of a ranking of candidates, we represent a mistake by a swap of adjacent candidates in a ballot. We find that for rules such as SNTV, k-Approval, and k-Borda, it is computationally easy to find the minimum number of swaps resulting in a change of an outcome. This task is, however, NP-hard for STV and the Chamberlin-Courant rule. We conclude our study of robustness with experimentally studying the average number of random swaps leading to a change of an outcome for several rules. Strategic voting in multiwinner elections. We ask whether a given group of cooperating voters can manipulate an election outcome in a favorable way. We focus on the k-Approval voting rule and we show that the computational complexity of answering the posed question has a rich structure. We spot several cases for which our problem is polynomial-time solvable. However, we also identify NP-hard cases. For several of them, we show how to circumvent the hardness by fixed-parameter tractability. We also present experimental studies indicating that our algorithms are applicable in practice. Diese Arbeit befasst sich mit der Untersuchung von Themen des Forschungsgebiets Computational Social Choice im Lichte realer Anwendungen. Dabei trägt sie zu einem besseren Verständnis der Bereiche der fairen Zuordnung und der Mehrgewinnerwahlen bei. Für beide Konzepte schlagen wir – inspiriert von realen Anwendungen – verschiedene neue Begriffe und Erweiterungen bestehender Modelle vor. Anschließend analysieren wir die Komplexität der Beantwortung von Berechnungsfragen, die durch die eingeführten Konzepte aufgeworfen werden. Dabei fokussieren wir uns auf die parametrisierte Komplexität. Hierzu identifizieren wir verschiedene Parameter, welche natürliche Merkmale der von uns untersuchten Berechnungsprobleme beschreiben. Durch die Nutzung dieser Parameter entwickeln wir erfolgreich effiziente Algorithmen für Spezialfälle der untersuchten Probleme. Wir ergänzen unsere Analyse indem wir zeigen, welche Parameter vermutlich nicht verwendet werden können um effiziente Algorithmen zu finden. Dabei zeichnen wir ein umfassendes Bild der Berechnungskomplexität der untersuchten Probleme. Insbesondere konzentrieren wir uns auf vier Themen, die wir, gruppiert nach unseren beiden Schwerpunkten, unten vorstellen. Für alle Themen bis auf eines präsentieren wir Experimente, die auf Implementierungen der von uns neu entwickelten Algorithmen basieren. Wir konzentrieren uns zunächst auf die faire Zuordnung unteilbarer Ressourcen. Hier betrachten wir eine Menge unteilbarer Ressourcen und eine Gruppe von Agenten. Jeder Agent gibt eine Bewertung des Nutzens jeder Ressource ab und die Aufgabe besteht darin, eine "faire" Zuordnung der Ressourcen zu finden, wobei jede Ressource höchstens einem Agenten zugeordnet werden kann. Innerhalb dieses Bereiches konzentrieren wir uns auf die beiden folgenden Problemstellungen. Der soziale Kontext bei der fairen Zuordnung unteilbarer Ressourcen. In vielen Szenarien, in denen Ressourcen zugeordnet werden sollen, ist es unwahrscheinlich, dass jeder Agent alle anderen kennt. Vorstellbar ist beispielsweise ein Szenario, in dem die Agenten Mitarbeiter eines großen Unternehmens repräsentieren. Es ist höchst unwahrscheinlich, dass jeder Mitarbeiter jeden anderen Mitarbeiter kennt. Motiviert durch solche Szenarien entwickeln wir ein neues Modell der graph-basierten Neidfreiheit. Wir erweitern den klassischen Neidfreiheitsbegriff um die sozialen Beziehungen von Agenten, die durch soziale Netzwerke modelliert werden. Einerseits zeigen wir, dass wenn das soziale Netzwerk der Agenten einfach ist (zum Beispiel, wenn es sich um einen gerichteten azyklischen Graph handelt), in manchen Fällen faire Zuordnungen effizient gefunden werden können. Andererseits stellen wir diesen algorithmisch positiven Ergebnissen mehrere NP-schweren Fällen entgegen. Ein Beispiel für einen solchen Fall sind soziale Netzwerke mit einem konstanten Knotengrad. Faire Zuteilung an wenige Agenten mit begrenzter Rationalität. Begrenzte Rationalität beschreibt die Idee, dass Menschen aufgrund kognitiver Grenzen dazu neigen, Probleme, mit denen sie konfrontiert werden, zu vereinfachen. Eine mögliche Folge dieser Grenzen ist, dass menschliche Agenten in der Regel einfache Bewertungen der gewünschten Ressourcen abgeben; beispielsweise könnten Agenten die verfügbaren Ressourcen nur in zwei Gruppen, erwünschte und unerwünschte Ressourcen, kategorisieren. Durch Anwendung von Techniken zum Lösen von Ganzzahligen Linearen Programmen zeigen wir, dass unter der Annahme einer kleinen Anzahl von Agenten die Ausnutzung begrenzter Rationalität dabei hilft, effiziente Algorithmen zum Finden neidfreier und Pareto-effizienter Zuweisungen zu entwickeln. Weiterhin zeigen wir, dass unser Ergebnis ein allgemeines Verfahren liefert, welches auf eine Reihe verschiedener Fairnesskonzepte angewendet werden kann, wie zum Beispiel Neidfreiheit bis auf ein Gut oder Neidfreiheit bis auf irgendein Gut. Auf diese Weise gewinnen wir effiziente Algorithmen für eine Reihe fairer Zuordnungsprobleme (wenige Agenten mit begrenzter Rationalität vorausgesetzt). Darüber hinaus zeigen wir empirisch, dass unsere Technik in der Praxis anwendbar ist. Weiterhin untersuchen wir Mehrgewinnerwahlen, bei denen uns eine Menge von Wählern sowie ihre Präferenzen über eine Reihe von Kandidaten gegeben sind. Das Ergebnis eines Mehrgewinnerwahlverfahrens ist eine Gruppe (oder eine Menge von Gruppen im Falle eines Unentschiedens) von Kandidaten, welche die Präferenzen der Wähler am besten einem bestimmten Ziel folgend widerspiegeln. In diesem Kontext untersuchen wir die folgenden Themen. Die Robustheit von Wahlergebnissen. Wir untersuchen, wie robust die Ergebnisse von Mehrgewinnerwahlen gegenüber möglicher Fehler der Wähler sind. Unter der Annahme, dass jeder Wähler eine Stimme in Form einer Rangliste von Kandidaten abgibt, modellieren wir einen Fehler als einen Tausch benachbarter Kandidaten in der Rangliste. Wir zeigen, dass für Wahlregeln wie SNTV, k-Approval und k-Borda die minimale Anzahl an Vertauschungen, welche zu einer Ergebnisänderung führt, einfach zu berechnen ist. Für STV und die Chamberlin-Courant-Regel ist diese Aufgabe allerdings NP-schwer. Wir schließen unsere Untersuchung der Robustheit unterschiedlicher Wahlregeln ab mit einer experimentellen Evaluierung der durchschnittlichen Anzahl zufälliger Vertauschungen, die zu einer Änderung des Ergebnisses führen. Strategische Abstimmung bei Wahlen mit mehreren Gewinnern. Wir fragen, ob eine bestimmte Gruppe von kooperierenden Wählern ein Wahlergebnis zu ihren Gunsten manipulieren kann. Dabei konzentrieren wir uns auf die k-Approval-Wahlregel. Wir zeigen, dass die Berechnungskomplexität der besagten Manipulation eine reiche Struktur besitzt. Auf der einen Seite identifizieren wir mehrere Fälle in denen das Problem in Polynomzeit lösbar ist. Auf der anderen Seite identifizieren wir jedoch auch NP-schwere Fälle. Für einige von ihnen zeigen wir, wie die Berechnungsschwere durch parametrisierte Algorithmen umgangen werden kann. Wir präsentieren zudem experimentelle Untersuchungen, welche darauf hindeuten, dass unsere Algorithmen in der Praxis anwendbar sind.

Download or read book Approval Compatible Voting Rules written by Jérôme Lang and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a classical voting situation, each voter in a group is asked to report a ranking over a set of alternatives, and a voting rule is applied to determine a winning alternative. But voters may also hold approval preferences, giving rise to an approval winner. If voters with approval preferences are asked to report rankings instead, and assuming that voters are sincere, can an approval winner possibly win the election? Can an approval loser lose the election, or can all approval co-winners be co-winners of the election? These three types of questions lead to different notions of approval compatibility for voting rules, called positive, negative, and uniform approval compatibility. We find that negative approval compatibility is a very weak notion, while uniform positive approval compatibility is a very strong one. We also show that positive approval compatibility as well as uniform negative approval compatibility divide usual voting rules into two significant families: Borda, plurality, plurality with runoff, STV, and Condorcet-consistent rules satisfy these notions, while several positional scoring rules (with Borda and Plurality excepted) violate them.

Download or read book Satisfaction Approval Voting written by Steven J. Brams and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We propose a new voting system, satisfaction approval voting (SAV), for multiwinner elections, in which voters can approve of as many candidates or as many parties as they like. However, the winners are not those who receive the most votes, as under approval voting (AV), but those who maximize the sum of the satisfaction scores of all voters, where a voter's satisfaction score is the fraction of his or her approved candidates who are elected. SAV may give a different outcome from A - in fact, SAV and AV outcomes may be disjoin - but SAV generally chooses candidates representing more diverse interests than does AV (this is demonstrated empirically in the case of a recent election of the Game Theory Society). A decision-theoretic analysis shows that all strategies except approving of a least-preferred candidate are undominated, so voters will often find it optimal to approve of more than one candidate. In party-list systems, SAV apportions seats to parties according to the Jefferson/d'Hondt method with a quota constraint, which favors large parties and gives an incentive to smaller parties to coordinate their policies and forge alliances, even before an election, that reflect their supporters' coalitional preferences.

Download or read book The Many Faces of Strategic Voting written by John H Aldrich and published by University of Michigan Press. This book was released on 2018-11-20 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Voters do not always choose their preferred candidate on election day. Often they cast their ballots to prevent a particular outcome, as when their own preferred candidate has no hope of winning and they want to prevent another, undesirable candidate’s victory; or, they vote to promote a single-party majority in parliamentary systems, when their own candidate is from a party that has no hope of winning. In their thought-provoking book The Many Faces of Strategic Voting, Laura B. Stephenson, John H. Aldrich, and André Blais first provide a conceptual framework for understanding why people vote strategically, and what the differences are between sincere and strategic voting behaviors. Expert contributors then explore the many facets of strategic voting through case studies in Great Britain, Spain, Canada, Japan, Belgium, Germany, Switzerland, and the European Union.

Download or read book Approval Voting written by Steven J. Brams and published by . This book was released on 1983 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Algorithmic aspects of resource allocation and multiwinner voting theory and experiments written by Andrzej Kaczmarczyk and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is concerned with investigating elements of computational social choice in the light of real-world applications. We contribute to a better understanding of the areas of fair allocation and multiwinner voting. For both areas, inspired by real-world scenarios, we propose several new notions and extensions of existing models. Then, we analyze the complexity of answering the computational questions raised by the introduced concepts. To this end, we look through the lens of parameterized complexity. We identify different parameters which describe natural features specific to the computational problems we investigate. Exploiting the parameters, we successfully develop efficient algorithms for spe- cific cases of the studied problems. We complement our analysis by showing which parameters presumably cannot be utilized for seeking efficient algorithms. Thereby, we provide comprehensive pictures of the computational complexity of the studied problems. Specifically, we concentrate on four topics that we present below, grouped by our two areas of interest. For all but one topic, we present experimental studies based on implementations of newly developed algorithms. We first focus on fair allocation of indivisible resources. In this setting, we consider a collection of indivisible resources and a group of agents. Each agent reports its utility evaluation of every resource and the task is to "fairly" allocate the resources such that each resource is allocated to at most one agent. We concentrate on the two following issues regarding this scenario. The social context in fair allocation of indivisible resources. In many fair allocation settings, it is unlikely that every agent knows all other agents. For example, consider a scenario where the agents represent employees of a large corporation. It is highly unlikely that every employee knows every other employee. Motivated by such settings, we come up with a new model of graph envy-freeness by adapting the classical envy-freeness notion to account for social relations of agents modeled as social networks. We show that if the given social network of agents is simple (for example, if it is a directed acyclic graph), then indeed we can sometimes find fair allocations efficiently. However, we contrast tractability results with showing NP-hardness for several cases, including those in which the given social network has a constant degree. Fair allocations among few agents with bounded rationality. Bounded rationality is the idea that humans, due to cognitive limitations, tend to simplify problems that they face. One of its emanations is that human agents usually tend to report simple utilities over the resources that they want to allocate; for example, agents may categorize the available resources only into two groups of desirable and undesirable ones. Applying techniques for solving integer linear programs, we show that exploiting bounded rationality leads to efficient algorithms for finding envy-free and Pareto-efficient allocations, assuming a small number of agents. Further, we demonstrate that our result actually forms a framework that can be applied to a number of different fairness concepts like envy-freeness up to one good or envy-freeness up to any good. This way, we obtain efficient algorithms for a number of fair allocation problems (assuming few agents with bounded rationality). We also empirically show that our technique is applicable in practice. Further, we study multiwinner voting, where we are given a collection of voters and their preferences over a set of candidates. The outcome of a multiwinner voting rule is a group (or a set of groups in case of ties) of candidates that reflect the voters' preferences best according to some objective. In this context, we investigate the following themes. The robustness of election outcomes. We study how robust outcomes of multiwinner elections are against possible mistakes made by voters. Assuming that each voter casts a ballot in a form of a ranking of candidates, we represent a mistake by a swap of adjacent candidates in a ballot. We find that for rules such as SNTV, k-Approval, and k-Borda, it is computationally easy to find the minimum number of swaps resulting in a change of an outcome. This task is, however, NP-hard for STV and the Chamberlin-Courant rule. We conclude our study of robustness with experimentally studying the average number of random swaps leading to a change of an outcome for several rules. Strategic voting in multiwinner elections. We ask whether a given group of cooperating voters can manipulate an election outcome in a favorable way. We focus on the k-Approval voting rule and we show that the computational complexity of answering the posed question has a rich structure. We spot several cases for which our problem is polynomial-time solvable. However, we also identify NP-hard cases. For several of them, we show how to circumvent the hardness by fixed-parameter tractability. We also present experimental studies indicating that our algorithms are applicable in practice.

Download or read book Handbook of Group Decision and Negotiation written by D. Marc Kilgour and published by Springer Science & Business Media. This book was released on 2010-08-02 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Publication of the Handbook of Group Decision and Negotiation marks a milestone in the evolution of the group decision and negotiation (GDN) eld. On this occasion, editors Colin Eden and Marc Kilgour asked me to write a brief history of the eld to provide background and context for the volume. They said that I am in a good position to do so: Actively involved in creating the GDN Section and serving as its chair; founding and leading the GDN journal, Group Decision and Negotiation as editor-in-chief, and the book series, “Advances in Group Decision and Negotiation” as editor; and serving as general chair of the GDN annual meetings. I accepted their invitation to write a brief history. In 1989 what is now the Institute for Operations Research and the Management Sciences (INFORMS) established its Section on Group Decision and Negotiation. The journal Group Decision and Negotiation was founded in 1992, published by Springer in cooperation with INFORMS and the GDN Section. In 2003, as an ext- sion of the journal, the Springer book series, “Advances in Group Decision and Negotiation” was inaugurated.