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on Collective Decision-Making |
| By: | Martin Bullinger; Chris Dong; Patrick Lederer; Clara Mehler |
| Abstract: | In approval-based committee (ABC) voting, the goal is to choose a subset of predefined size of the candidates based on the voters' approval preferences over the candidates. While this problem has attracted significant attention in recent years, the incentives for voters to participate in an election for a given ABC voting rule have been neglected so far. This paper is thus the first to explicitly study this property, typically called participation, for ABC voting rules. In particular, we show that all ABC scoring rules even satisfy group participation, whereas most sequential rules severely fail participation. We furthermore explore several escape routes to the impossibility for sequential ABC voting rules: we prove for many sequential rules that (i) they satisfy participation on laminar profiles, (ii) voters who approve none of the elected candidates cannot benefit by abstaining, and (iii) it is NP-hard for a voter to decide whether she benefits from abstaining. |
| Date: | 2023–12 |
| URL: | http://d.repec.org/n?u=RePEc:arx:papers:2312.08798&r=cdm |
| By: | Anton Kolotilin (School of Economics, UNSW); Alexander Wolitzky (Department of Economics, MIT) |
| Abstract: | We study the problem of a partisan gerrymanderer who assigns voters to equipopulous districts so as to maximize his party’s expected seat share. The designer faces both aggregate uncertainty (how many votes his party will receive) and idiosyncratic, voter-level uncertainty (which voters will vote for his party). We argue that pack-and-pair districting, where weaker districts are “packed” with a single type of voter, while stronger districts contain two voter types, is typically optimal for the gerrymanderer. The optimal form of pack-and-pair districting depends on the relative amounts of aggregate and idiosyncratic uncertainty. When idiosyncratic uncertainty dominates, it is optimal to pack opposing voters and pair more favorable voters; this plan resembles traditional “packing-and-cracking.” When aggregate uncertainty dominates, it is optimal to pack moderate voters and pair extreme voters; this “matching slices” plan has received some attention in the literature. Estimating the model using precinct-level returns from recent US House elections indicates that, in practice, idiosyncratic uncertainty dominates and packing opponents is optimal; moreover, traditional pack-and-crack districting is approximately optimal. We discuss implications for redistricting reform and political polarization. Methodologically, we exploit a formal connection between gerrymandering—partitioning voters into districts—and information design—partitioning states of the world into signals. |
| Keywords: | Gerrymandering, pack-and-crack, matching slices, pack-and-pair, information design |
| JEL: | C78 D72 D82 |
| Date: | 2023–04 |
| URL: | http://d.repec.org/n?u=RePEc:swe:wpaper:2023-06&r=cdm |
| By: | Chris Dang; Patrick Lederer |
| Abstract: | In approval-based committee (ABC) elections, the goal is to select a fixed-size subset of the candidates, a so-called committee, based on the voters' approval ballots over the candidates. One of the most popular classes of ABC voting rules are ABC scoring rules, which have recently been characterized by Lackner and Skowron (2021). However, this characterization relies on a model where the output is a ranking of committees instead of a set of winning committees and no full characterization of ABC scoring rules exists in the latter standard setting. We address this issue by characterizing two important subclasses of ABC scoring rules in the standard ABC election model, thereby both extending the result of Lackner and Skowron (2021) to the standard setting and refining it to subclasses. In more detail, by relying on a consistency axiom for variable electorates, we characterize (i) the prominent class of Thiele rules and (ii) a new class of ABC voting rules called ballot size weighted approval voting. Based on these theorems, we also infer characterizations of three well-known ABC voting rules, namely multi-winner approval voting, proportional approval voting, and satisfaction approval voting. |
| Date: | 2023–12 |
| URL: | http://d.repec.org/n?u=RePEc:arx:papers:2312.08799&r=cdm |
| By: | Franck, Raphaël; Gay, Victor |
| Abstract: | This study argues that urbanization changed the relationship between the occupation of candidates running in parliamentary elections and their electoral success. To identify local-level variation in urbanization, we leverage exogenous changes to the boundaries of electoral constituencies in the 1928, 1932, and 1936 French parliamentary elections. The results suggest that urbanization was detrimental to the electoral success of lawyers but beneficial to that of employees and workers. This electoral effect of urbanization was especially felt on the left of the political spectrum, whereby left-wing employees and workers crowded out left-wing lawyers. |
| Keywords: | Elections, Political Representation, Urbanization |
| JEL: | D72 K16 N44 N94 |
| Date: | 2024 |
| URL: | http://d.repec.org/n?u=RePEc:zbw:glodps:1366&r=cdm |
| By: | Anesti, Vincent (Department of Economics and Management, University of Luxembourg); Buisseret, Peter (Department of Government, Harvard University,) |
| Abstract: | We develop a dynamic model in which a group collectively bargains with an external party. At each date the group makes an offer to the external party (the ‘agent’) in exchange for a concession. Group members hold heterogeneous preferences over agreements and are uncertain about the agent’s resolve. We show that all group members favor more aggressive proposals than they would if they were negotiating alone. By eliciting more information about the agent’s resolve, these offers reduce the group members’ uncertainty about the agent’s preferences and therefore reduce the group’s internal conflicts over its negotiating strategy. To mitigate the consequent risk that negotiations fail, decisive group members successively give up their influence over proposals: starting from any initially democratic decision process, the group eventually consolidates its entire negotiation authority into the hands of a single member. |
| Keywords: | Adverse selection ; collective choice ; political economy ; dictatorship ; bargaining. JEL codes: D02 ; D71 ; D78 ; D82 ; L22 |
| Date: | 2023 |
| URL: | http://d.repec.org/n?u=RePEc:wrk:wcreta:81&r=cdm |
| By: | Rida Laraki (LAMSADE - Laboratoire d'analyse et modélisation de systèmes pour l'aide à la décision - Université Paris Dauphine-PSL - PSL - Université Paris sciences et lettres - CNRS - Centre National de la Recherche Scientifique) |
| Abstract: | The majority judgment (MJ) voting method works well in theory and in practice. Not only does MJ avoid the classical Condorcet and Arrow paradoxes, but it also overcomes the domination paradox, from which paired comparisons by majority rule, approval voting, and all Condorcet consistent methods suffer. This article also shows why MJ best reduces the impact of strategic manipulation and minimizes ties to the extreme. The article illustrates the resistance of MJ to manipulations in a real example, discusses other salient properties of MJ, and summarizes several recent applications that show MJ to be, despite its newness, the right basis of electoral reform. |
| Keywords: | Majority Judgment, Arrow paradox, Domination paradox, Resistance to strategy, Range voting, Approval voting, Rank choice voting, Condorcet paradox |
| Date: | 2022 |
| URL: | http://d.repec.org/n?u=RePEc:hal:journl:hal-04304795&r=cdm |
| By: | Ralph-Christopher Bayer (School of Economics and Public Policy, The University of Adelaide.); Marco Faravelli (University of Queensland); Carlos Pimienta (UNSW School of Economics) |
| Abstract: | We show in a novel voting model with costly information acquisition that in equilibrium nobody votes without acquiring information and that the probability of the better alternative winning converges to one as the size of the electorate approaches infinity. In a large-scale internet experiment during the US Presidential Election, we find alarming rates of uninformed voting (>42 percent). The problem is exacerbated in treatments that allow for expressive voting motives and overconfidence (rates up to 56 percent). Increasing the electorate size substantially raises efficiency, as long as uninformed voting is not too biased towards one alternative. |
| Keywords: | Costly information acquisition, Condorcet Jury Theorem, Uninformed voting, Wisdom of the crowd |
| JEL: | C90 D72 C72 |
| Date: | 2023–04 |
| URL: | http://d.repec.org/n?u=RePEc:swe:wpaper:2023-08&r=cdm |
| By: | Pérez-Asurmendi, Patrizia; de Andrés Calle, Rocío |
| Abstract: | This contribution deals with the measurement of the concordance between two characteristics reported by individuals at different points in time. Although intuition tell us that the declared opinion would be the same each time, the evidence does not always show it. In these cases, several measures for calculating agreement can be found in the literature, but by using them, much of the available information is lost, since they do not take disagreement into account. To overcome this drawback, we propose to use Cohen’s Kappa statistic, which is an easy-to- interpret tool to measure the agreement between two categorical characteristics considering also the disagreement. To illustrate its applicability, we analyze the concordance between declared voting intention and voting decision, and between declared sympathy for political parties before and after the election with data from the 2015 General Election in Spain. |
| Keywords: | Cohen’s Kappa statistic; Concordance; Categorical data; Voting behaviour |
| JEL: | C10 D72 Z13 |
| Date: | 2023–12–05 |
| URL: | http://d.repec.org/n?u=RePEc:pra:mprapa:119372&r=cdm |
| By: | Leonardo Becchetti (CEIS & DEF, University of Rome "Tor Vergata"); Gianluigi Conzo (University of Rome "Tor Vergata") |
| Abstract: | Based on the horizontal differentiation literature we model decline in voter turnout as a rational choice when the distance between the voter and the closest party on the hyperplane of political preferences is regarded as too high by the voter. To analyse political preferences we consider five crucial segments going beyond the traditional left-right scale simplification (climate, migration, security, civil rights and income distribution). Our empirical findings on 32 countries in the last eight waves of the European Social Survey (ESS) support our research hypothesis: respondents who do not feel close to any party (57 percent of the sample) are more likely to abstain (23 percent of the sample). Results are confirmed when we use the Chapel Hill Expert Survey (CHES) classification of political party positions to calculate distance. We as well show that those who declare to feel distant from political parties are significantly less concerned with climate and civil rights, while significantly more with income distribution, migration threat and security, as well as having lower education and belonging to lower income deciles. We conclude by arguing that the success of populist parties in the last decade is probably related to their higher capacity to identify characteristics of non voters and moving toward their preferences. |
| Keywords: | turnout, hotelling differentiation, environment, civil rights |
| Date: | 2023–12–19 |
| URL: | http://d.repec.org/n?u=RePEc:rtv:ceisrp:569&r=cdm |
| By: | Wesley H. Holliday; Eric Pacuit |
| Abstract: | May's Theorem [K. O. May, Econometrica 20 (1952) 680-684] characterizes majority voting on two alternatives as the unique preferential voting method satisfying several simple axioms. Here we show that by adding some desirable axioms to May's axioms, we can uniquely determine how to vote on three alternatives. In particular, we add two axioms stating that the voting method should mitigate spoiler effects and avoid the so-called strong no show paradox. We prove a theorem stating that any preferential voting method satisfying our enlarged set of axioms, which includes some weak homogeneity and preservation axioms, agrees with Minimax voting in all three-alternative elections, except perhaps in some improbable knife-edged elections in which ties may arise and be broken in different ways. |
| Date: | 2023–12 |
| URL: | http://d.repec.org/n?u=RePEc:arx:papers:2312.14256&r=cdm |
| By: | Marc S. Jacob (ETH Zurich); Barton E. Lee (ETH Zurich); Gabriele Gratton (UNSW Business School) |
| Abstract: | We propose a mechanism linking legislative gridlock to voters’ support for candidates who hold extreme policy positions. Moderate voters rationally discount extreme policy proposals from co-partisans on gridlocked policy issues because on these issues policy change is unlikely. We test our mechanism in a large-scale online experiment in which we randomly vary subjects’ perceptions of gridlock and measure subjects’ support for co-partisan candidates in candidate-choice tasks. We verify that greater perception of gridlock increases moderate subjects’ propensity to vote for extreme co-partisan candidates. We show that our experimental evidence is consistent with our mechanism and that other mechanisms are less likely to underlie our main result. Our theory offers a causal connection from gridlock to elite polarization that may inform further empirical work and suggests a novel tradeoff between elite polarization and policy stability in constitutional design. |
| Date: | 2023–07 |
| URL: | http://d.repec.org/n?u=RePEc:swe:wpaper:2023-11&r=cdm |
| By: | Niclas Boehmer; Markus Brill; Alfonso Cevallos; Jonas Gehrlein; Luis S\'anchez-Fern\'andez; Ulrike Schmidt-Kraepelin |
| Abstract: | We provide the first large-scale data collection of real-world approval-based committee elections. These elections have been conducted on the Polkadot blockchain as part of their Nominated Proof-of-Stake mechanism and contain around one thousand candidates and tens of thousands of (weighted) voters each. We conduct an in-depth study of application-relevant questions, including a quantitative and qualitative analysis of the outcomes returned by different voting rules. Besides considering proportionality measures that are standard in the multiwinner voting literature, we pay particular attention to less-studied measures of overrepresentation, as these are closely related to the security of the Polkadot network. We also analyze how different design decisions such as the committee size affect the examined measures. |
| Date: | 2023–12 |
| URL: | http://d.repec.org/n?u=RePEc:arx:papers:2312.11408&r=cdm |