CONDORCET

“CONDORCET” is a project of the PEPR program « Mathématiques en interaction » (Maths-ViVES, axis society), funded by France 2030, with code name ANR-24-EXMA-001.

It gathers a consortium of mathematicians, economists, computer scientists, and political scientists, who aim to compare the properties of different voting systems, and to enable the public and the decision-makers to take advantage of this new research.

PEPR MATHS-VivES CONDORCET program

While the name “CONDORCET” indeed refers to Marie Jean Antoine Nicolas de Caritat, marquis de Condorcet, a mathematician and philosopher of the Enlightenment who was famous for his analysis of voting systems, the acronym here stands for the project  » CONsolidating DemOcRacy: Choosing an Electoral method transparently. »

The CONDORCET project aims to compare the properties of different voting systems and to enable the public and the decision-makers to take advantage of this new research.

CONDORCET is a selected project, in the PEPR program Mathematics in Interaction (Maths-VivES, France 2030). It runs from October 2025 to June 2029. The project’s principal investigators are the mathematician Jean-Baptiste Aubin and the economist Antoinette Baujard. The CONDORCET steering committee includes Jean-Baptiste Aubin (INSA, ICJ), Antoinette Baujard (Université Jean Monnet Saint-Etienne, Gate Lyon Saint-Etienne), Antoine Rolland (Université Lyon 2, ERIC) and Irène Gannaz (INP Grenoble, G-SCOP). The coordinating partners are INSA Lyon, GATE at CNRS, ERIC at Université Lyon 2, and INP Grenoble. The CONDORCET strategic committee includes personalities from laboratories of ideas on democracy, artists and human sciences academics. The CONDORCET consortium includes over twenty mathematicians, economists, computer scientists, and political scientists from various centers in France and beyond, well recognized for their academic work and their experience in scientific outreach.

Four working packages to compare voting rules in a meaningful way

Social choice theory can compare voting procedures based on given assumptions about individual preferences, whether these are based on rankings of all candidates (as in the case of single-winner plurality, two-round, or Borda voting), or on the evaluation of each candidate (as in the case of approval voting, evaluation voting, or majority judgment voting). However, there is currently no unified framework for comparing these families of procedures. The project is designed to break this deadlock in four complementary working packages.

WP1. The project aims to explore two mathematical lines of inquiry: applying depth functions (and optimal transport) to characterize voting rules, and broadening the scope of axiomatics to encompass assumptions about preferences.

WP2. Given that comparisons between voting rules can only be useful to decision-makers if the results are interpreted in contexts which are familiar to them, the project aims to carry out simulations based on different preference distribution models, notably calibrated with real electoral databases.

WP3. Comparing voting systems also requires testing, through controlled laboratory experiments or surveys using representative samples, whether theoretical properties remain valid with real actual electoral behavior. The project also aims to study the complementary properties of voting systems, such as their explicability, their propensity for polarization or consensus, or the various determinants of voter satisfaction.

WP4. We hope to enable decision-makers, citizens, community stakeholders and elected officials to select a voting system with full awareness, and without being influenced by our own preferences. Beyond academic publications, the program therefore values dialogue with civil society partners and public decision-makers, and it places great emphasis on scientific mediation, planning to organize public conferences, comic books, documentary films, school visits, continuing education and an interactive website.

Events

The CONDORCET Consortium, Kick-off meeting, Lyon, Nov 27, 2025.
  • Nov. 27-28, 2025, Kick-off meeting INSA Lyon
  • Mardi 17 mars (IHP, Paris), journées annuelles du PEPR Math Vives
  • April 23-24, 2026, 4th Saint-Etienne Amsterdam Workshop on Social Choice, Saint-Etienne.
  • May 12, 2026, Workshop on simulations, Lyon MSH.
  • June 30 2026, Workshop Condorcet on Depth functions and axiomatics
  • CONDORCET organizes the second meeting of the Réseau des études électorales en France (REEF) in INSA Lyon on July 3, 2026.

Links

Tools and apps

  • You need to vote, you wish to use a standard or original voting rule. Use The WHALE website, by Sylvain Bouveret: Which Alternative is elected?
  • In the context of the French municipal election, a big issue concerns which fusions of lists would be fair or unfair for which party. Here is an analysis and a tool, by Theo Delemazure, Antoine Prevotat et Jérôme Lang.

News of the consortium

  • The CONDORCET program has recruited Jacques-Anderson Kouassi for a PhD position in Grenoble G-SCOP; He started last Nov. 2025.
  • The CONDORCET program has recruited Lily Savey for a post-doc position in social choice and experimental economics. She will start next Sept. 21, 2026 in Saint-Etienne, GATE.
  • Last COPIL took place on June 30, 2026; next will be Oct. 14, 2026.
  • Next gathering event of the CONDORCET consortium will be in June 2026.
  • The 2nd REEF meeting will be organized in INSA Lyon, on July 3rd, 2026.
  • The next SSCW conference will be organized by GATE Lyon Saint-Etienne, Université Jean Monnet in Lyon in June-July 2028. It will be supported by PEPR CONDORCET.

Publications

Articles

HAL - Publications Théo Delemazure, Roberto Brunetti, Antoinette Baujard, Sylvain Bouveret. Do grades have absolute meaning? An experiment on majority judgment. Social Choice and Welfare, 2026, ⟨10.1007/s00355-026-01665-7⟩. ⟨halshs-05664566⟩

Antoinette Baujard, Jean-François Laslier. La participation des citoyens aux expérimentations sur les modes de scrutin. Revue Economique, 2025, Vol. 76 (5), pp.839-860. ⟨10.3917/reco.765.0839⟩. ⟨halshs-05560583⟩

Antoinette Baujard, Roberto Brunetti, Isabelle Lebon, Simone Marsilio. How people understand voting rules. Public Choice, 2025, ⟨10.1007/s11127-025-01344-8⟩. ⟨hal-05423963v4⟩

Antoinette Baujard, Isabelle Lebon. Retelling the Story of the 2017 French Presidential Election: The contribution of Approval Voting. Homo Oeconomicus: Journal of Behavioral and Institutional Economics, 2025, 42 (1), pp.65-86. ⟨10.1007/s41412-022-00134-7⟩. ⟨hal-03886491⟩

Working papers

HAL - Publications Roberto Brunetti. Municipalities' Voting Power and Housing Supply: Evidence from French Intermunicipal Cooperation. 2026. ⟨hal-05642466⟩

Élie de Panafieu, François Durand, Jérôme Lang. The Communication Complexity of Instant-Runoff Voting. 2026. ⟨hal-05566718⟩

Théo Delemazure, Roberto Brunetti, Antoinette Baujard, Sylvain Bouveret. Do Grades Have Absolute Meaning ? An Experiment on Majority Judgment. 2026. ⟨hal-05114129v2⟩

Jean-Baptiste Aubin, Antoine Rolland, Ioana Gavra, Irène Gannaz, Jacques Anderson Kouassi. Deepest voting on rankings. 2026. ⟨hal-05552255⟩

Scientific mediation

CONDORCET is committed to communicate research on voting rules extensively to a wide public, e.g.

  • Antoine Rolland « les maths au secours de la démocratie », : lundi 16 mars (IHP, Paris), « maths en action » : rencontre entre des scientifiques et des lycéennes et lycéens de la région parisienne à l’occasion de la 15ème semaine des mathématiques.
  • Jean-Baptiste Aubin, exposé sur les règles de vote, high-school internship, ICJ, juin 2026.

And in the media