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on Collective Decision-Making |
| By: | Yunus C. Aybas; Oguzhan Celebi; Surabhi Dutt |
| Abstract: | State delegations are often chosen through single-member district elections, creating a tension between respecting district majorities and reflecting the statewide electorate. First-past-the-post (FPTP) follows each district's majority but can yield a delegation seat share far from the party's statewide vote share. In contrast, proportional representation (PR), which makes a party's seat share correspond to its statewide vote share, requires departing from local majorities in some districts. We measure misrepresentation as a weighted sum of within-district misrepresentation, measured by the share of voters locally represented by their non-preferred party, and statewide misrepresentation, measured by the deviation of a party's seat share from its statewide vote share. The misrepresentation-minimizing rule is a cutoff rule determined by the relative weight of statewide misrepresentation. As this weight rises, the cutoff continuously shifts from FPTP's 50% to the PR cutoff that aligns the delegation's seat share with statewide vote shares. This shift makes gerrymandering harder, offering an alternative lever to limit gerrymandering. Using a majorization-based metric of geographic concentration, we show that concentrating support reduces misrepresentation only under the misrepresentation-minimizing rule. Within this class, FPTP and PR are uniquely characterized by the absence of cross-district spillovers and by gerrymandering-proofness, respectively. Using U.S. House elections, we infer the weights that rationalize outcomes, offering a novel metric for evaluating representativeness of district boundaries and electoral reform proposals. |
| Date: | 2026–02 |
| URL: | https://d.repec.org/n?u=RePEc:arx:papers:2602.12910 |
| By: | Clara Ponsati; Jan Zapal |
| Abstract: | A finite group of voters must elect the pope from a finite set of candidates. They repeatedly cast ballots (possibly for ever) until one candidate attains at least Q votes. A candidate is electable—if enough voters prefer him to a continuous disagreement—as well as stable—if no other candidate is preferred to him by a sufficient number of voters. We provide a necessary and sufficient condition for the existence of a candidate that is both electable and stable. When there are three candidates and voters are willing to compromise somewhat, the condition requires choice by two-thirds supermajority, which coincides with the procedure that the Catholic Church has used to appoint the pope for almost a millennium. |
| Keywords: | repeated ballots, conclave, pope, electable, stable, supermajority |
| JEL: | D71 D72 Z12 |
| Date: | 2026–02 |
| URL: | https://d.repec.org/n?u=RePEc:cer:papers:wp815 |
| By: | Federico Fioravanti; Zoi Terzopoulou |
| Abstract: | This work contributes to a foundational question in economic theory: how do individual-level cognitive biases interact with collective choice mechanisms? We study a setting where voters hold intrinsic preference rankings over a set of alternatives but cast approval ballots to determine the collective outcome. The ballots are shaped by an anchoring bias: alternatives are presented sequentially by a social planner, and a voter approves an alternative if and only if it is acceptable and strictly preferred to all alternatives previously encountered. We first analyze which approval-based voting rules are anchor-proof, in the sense that they always select the same winner regardless of the presentation order. We show that this requirement is extremely demanding: only very restrictive rules satisfy it. We then turn to the potential influence of the social planner. On the upside, when the planner has no information about the voters' intrinsic preferences, she cannot manipulate the outcome. |
| Date: | 2026–02 |
| URL: | https://d.repec.org/n?u=RePEc:arx:papers:2602.04494 |
| By: | Alexandre Chirat (CRESE - Centre de REcherches sur les Stratégies Economiques (UR 3190) - UFC - Université de Franche-Comté - UBFC - Université Bourgogne Franche-Comté [COMUE]); Cyril Hédoin (REGARDS - Recherches en Économie Gestion AgroRessources Durabilité Santé- EA 6292 - URCA - Université de Reims Champagne-Ardenne - MSH-URCA - Maison des Sciences Humaines de Champagne-Ardenne - URCA - Université de Reims Champagne-Ardenne, CRIEG - Centre de Recherche Interdisciplinaire Economie Gestion - MSH-URCA - Maison des Sciences Humaines de Champagne-Ardenne - URCA - Université de Reims Champagne-Ardenne) |
| Abstract: | This paper deduces conditions under which populism successfully emerges in democratic contexts. Building on Downs's economic theory of democracy, it hinges on three assumptions: uncertainty, rationality, and democratic stability. This theory considers three main types of agents: citizens, political parties, and information providers. We demonstrate that the necessary and sufficient conditions for a populist party to emerge and gain significant electoral support are 1) a political disequilibrium between demand (citizens' preferences) and supply (parties' platforms) combined with 2) democratic instability due to ideological polarization. Such conditions provide the rationale behind populist anti-elitism and its thin nature as an ideology. Since this paper provides a theoretical account of populism that, while sharing Downsian roots, differs from main political economy models of populism, we provide a systematic comparison. In particular, we show that the conditions under which the Median Voter Theorem is relevant are at odds with the conditions required to account for populism. |
| Keywords: | Populism -Uncertainty -Rationality -Public interest -democratic stability |
| Date: | 2025–11–02 |
| URL: | https://d.repec.org/n?u=RePEc:hal:journl:hal-05414427 |
| By: | Yifan Lin; Shenyu Qin; Kangning Wang; Lirong Xia |
| Abstract: | We study the committee selection problem in the canonical impartial culture model with a large number of voters and an even larger candidate set. Here, each voter independently reports a uniformly random preference order over the candidates. For a fixed committee size $k$, we ask when a committee can collectively beat every candidate outside the committee by a prescribed majority level $\alpha$. We focus on two natural notions of collective dominance, $\alpha$-winning and $\alpha$-dominating sets, and we identify sharp threshold phenomena for both of them using probabilistic methods, duality arguments, and rounding techniques. We first consider $\alpha$-winning sets. A set $S$ of $k$ candidates is $\alpha$-winning if, for every outside candidate $a \notin S$, at least an $\alpha$-fraction of voters rank some member of $S$ above $a$. We show a sharp threshold at \[ \alpha_{\mathrm{win}}^\star = 1 - \frac{1}{k}. \] Specifically, an $\alpha$-winning set of size $k$ exists with high probability when $\alpha \alpha_{\mathrm{win}}^\star$. We then study the stronger notion of $\alpha$-dominating sets. A set $S$ of $k$ candidates is $\alpha$-dominating if, for every outside candidate $a \notin S$, there exists a single committee member $b \in S$ such that at least an $\alpha$-fraction of voters prefer $b$ to $a$. Here we establish an analogous sharp threshold at \[ \alpha_{\mathrm{dom}}^\star = \frac{1}{2} - \frac{1}{2k}. \] As a corollary, our analysis yields an impossibility result for $\alpha$-dominating sets: for every $k$ and every $\alpha > \alpha_{\mathrm{dom}}^\star = 1 / 2 - 1 / (2k)$, there exist preference profiles that admit no $\alpha$-dominating set of size $k$. This corollary improves the best previously known bounds for all $k \geq 2$. |
| Date: | 2026–02 |
| URL: | https://d.repec.org/n?u=RePEc:arx:papers:2602.04815 |