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on Collective Decision-Making |
| By: | Federico Fioravanti; Zoi Terzopoulou |
| Abstract: | When voters evaluate alternatives sequentially, an anchoring bias makes their ballots depend on the order in which alternatives are presented. For approval ballots, no non-constant voting rule is robust to this dependence. We show that ranked ballots change the picture sharply: a rank-based rule is robust to the presentation order if and only if it is tops-only. Robustness to anchoring is thus available, but only at the price of ignoring everything a voter reports beyond her favourite alternative. |
| Date: | 2026–10 |
| URL: | https://d.repec.org/n?u=RePEc:arx:papers:2610.10316 |
| By: | Paula González (Universidad Pablo de Olavide); Francesca Passarelli (Universidad de Oviedo); Yolanda F. Rebollo-Sanz (Universidad Pablo de Olavide) |
| Abstract: | Using data on nearly 190, 000 candidates across five Spanish municipal elections (2003–2019), we estimate the causal effect of electoral defeat on party switching. We combine a high-dimensional fixed effects panel model with a regression discontinuity design exploiting the quasi-random assignment of council seats under Spain’s closed-list D’Hondt system. Both approaches yield consistent evidence that not securing a council seat is associated with a higher probability of changing party affiliation by 2.1 to 2.3 percentage points—a 13.5% to 14.5% relative increase. Additionally, regression estimates show that party switching is more strongly linked to better future electoral outcomes among non-elected switchers than among candidates who switch while holding a seat. Our results support the theory that politicians are primarily motivated by office-seeking ambitions and highlight the strategic nature of party switching in local politics. |
| Keywords: | party switching, party labels, political defectors, closed-list systems, politicians, office-seeking ambition, Spain, municipal elections, local randomization, regression discontinuity. |
| JEL: | D72 H11 C21 |
| Date: | 2026 |
| URL: | https://d.repec.org/n?u=RePEc:pab:wpaper:26.03 |
| By: | Raša Karapandža; Yaw Nyarko |
| Abstract: | Large language models (LLMs) increasingly provide economic and financial advice. We develop a microeconomic framework for understanding this role. We prove that an LLM acts like a voting rule: each input text is an election, possible continuations are candidates, and output probabilities are vote shares derived from the training corpus. Such rules can generate Condorcet cycles, implying intransitive pairwise recommendations and potential money-pump exploitation. Using ChatGPT-4o, we identify millions of cycles in pairwise investment choices among S&P 100 firms. Our theorems establish the voting interpretation on the training data and support its use off-sample. We also show that correcting cycles ex post is generally infeasible. Finally, temperature changes the voting rule: at T = 1, outputs are sampled in proportion to vote shares; lower temperatures favor the plurality winner, whereas higher temperatures flatten probabilities toward uniformity. |
| JEL: | D81 D83 D91 G41 |
| Date: | 2026–10 |
| URL: | https://d.repec.org/n?u=RePEc:nbr:nberwo:35839 |
| By: | Marina Diakonova (Banco de España); Julia Estefania-Flores (Banco de España); Corinna Ghirelli (Banco de España); Ana Peñalosa (Banco de España); Javier J. Pérez (Banco de España); Aitana Simó (Banco de España) |
| Abstract: | We propose a narrative-based approach to construct high-frequency measures of political polarization and legislative gridlock for seven democracies: France, Germany, Spain, Italy, the United Kingdom, the United States and Canada. Our indices reveal that polarization has risen markedly since the Global Financial and Sovereign Debt Crises, with a faster increase in North America than in Europe. Through a range of exercises we show that the two indices respond differently to elections and unified government control, and that the latter weakens the pass-through between political polarization and gridlock. Consistent with the literature, we also find that investment declines following an increase in either index. Together, these high-frequency, cross-country measures provide a new tool for comparative political economy analysis. |
| Keywords: | political polarization, legislative gridlock, textual analysis, cross-country analysis |
| JEL: | D72 D74 H3 P16 |
| Date: | 2026–10 |
| URL: | https://d.repec.org/n?u=RePEc:bde:wpaper:2636e |
| By: | Ezra Einy; Ori Haimanko |
| Abstract: | It is known that completeness of the coalitional ($C$-)desirability relation in a simple game does not imply the existence of a weighted-majority representation. We show that weightedness is implied in an approximate sense. Call an $n$-player simple game $\varepsilon$-weighted if, for some weight vector in the $(n-1)$-simplex, any losing coalition weight exceeds any winning coalition weight by at most $\varepsilon$; let $\varepsilon^{\ast}$ be the smallest such $\varepsilon$. We establish an upper bound on $\varepsilon^{\ast}$ in a general $C$-complete game, and deduce that, if all classes of equally desirable players become large asymptotically but the number of classes is bounded, then $\varepsilon^{\ast}=O(1/n_{\min})$ for the minimal player class size $n_{\min}$, and the bound is tight. Importantly, the minimal attainable fraction $\delta$ of coalitions mislabeled by a weighting rule also tends to $0$ when $n_{\min}\rightarrow\infty$ and the number of player classes is bounded, with $\delta=O(1/\sqrt{n_{\min}})$. |
| Date: | 2026–10 |
| URL: | https://d.repec.org/n?u=RePEc:arx:papers:2610.08968 |
| By: | Eric Zitzewitz |
| Abstract: | As prediction markets become more prominent, there are concerns that they will be a conduit for political bias. I analyze prediction markets returns from 1880 to 2025 and find no evidence of an overpricing of either left or right-leaning candidates, across a variety of subsamples. In recent elections, there is also no overpricing of either male or female, white or non-white, or young or old candidates. Most political prediction markets exhibit a favorite-longshot bias, and markets on near-term polling averages exhibit a very small overpricing of left-leaning outcomes (e.g., President Trump’s approval falling), which is detectable only because the sample size is large. For elections, however, despite attracting participants who may not be representative of the voting population, prediction markets yield predictions without systematic bias. |
| JEL: | G13 G4 P0 |
| Date: | 2026–10 |
| URL: | https://d.repec.org/n?u=RePEc:nbr:nberwo:35846 |