Agreement, Diversity, and Polarization Indices for Approval Elections

Faliszewski, Piotr; Mertlová, Jitka; Sornat, Krzysztof; Szufa, Stanisław; Wąs, Tomasz

doi:10.24963/ijcai.2026/377

Agreement, Diversity, and Polarization Indices for Approval Elections

Piotr Faliszewski, Jitka Mertlová, Krzysztof Sornat, Stanisław Szufa, Tomasz Wąs

Download BibTeX Cite

Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence. Main Track. Pages 3393-3401.

https://doi.org/10.24963/ijcai.2026/377

Keywords

Game Theory and Economic Paradigms: Computational social choice

Abstract

An index is a function that measures the extent to which an election has a particular feature. We seek indices that capture agreement, diversity, and polarization among voters in approval elections, normalized with respect to saturation. The latter means that if two elections differ by the fraction of candidates approved by an average voter, but otherwise are of similar nature, then they should have similar index values. We propose several indices, analyze their properties, and use them to derive a new map of approval elections, and compare various real-life elections from Pabulib, Preflib and other sources.

Piotr Faliszewski, Jitka Mertlová, Krzysztof Sornat, Stanisław Szufa, and Tomasz Wąs. 2026. Agreement, Diversity, and Polarization Indices for Approval Elections. In Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence, IJCAI-26. IJCAI, 3393–3401. https://doi.org/10.24963/ijcai.2026/377

@inproceedings{ijcai2026p377,
  title     = {Agreement, Diversity, and Polarization Indices for Approval Elections},
  author    = {Faliszewski, Piotr and Mertlová, Jitka and Sornat, Krzysztof and Szufa, Stanisław and Wąs, Tomasz},
  booktitle = {Proceedings of the Thirty-Fifth International Joint Conference on
               Artificial Intelligence, {IJCAI-26}},
  publisher = {International Joint Conferences on Artificial Intelligence Organization},
  editor    = {Diego Calvanese},
  pages     = {3393--3401},
  year      = {2026},
  month     = {8},
  note      = {Main Track},
  doi       = {10.24963/ijcai.2026/377},
  url       = {https://doi.org/10.24963/ijcai.2026/377},
}

TY  - CPAPER
TI  - Agreement, Diversity, and Polarization Indices for Approval Elections
AU  - Faliszewski, Piotr
AU  - Mertlová, Jitka
AU  - Sornat, Krzysztof
AU  - Szufa, Stanisław
AU  - Wąs, Tomasz
T2  - Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence, IJCAI-26
PB  - International Joint Conferences on Artificial Intelligence Organization
PY  - 2026
SP  - 3393
EP  - 3401
DO  - 10.24963/ijcai.2026/377
UR  - https://doi.org/10.24963/ijcai.2026/377
ER  -