Fair and Explainable Collective Decision

Local organizing committee

• Chloé Le Bail (LISN, Université Paris-Saclay)
• Vincent Mousseau (MICS, CentraleSupélec, Université Paris-Saclay)
• Wassila Ouerdane (MICS, CentraleSupélec, Université Paris-Saclay)
• Fabien Tarissan (CNRS, ENS Paris-Saclay)
• Anaëlle Wilczynski (MICS, CentraleSupélec, Université Paris-Saclay)

Fair and Explainable Collective Decision

Many real-life problems involve making a collective decision. One can cite, e.g., the choice of projects to fund in cities, or the assignment of students to courses or universities (see, e.g., in France the Parcoursup application for graduate studies). The former problem is known as participatory budgeting, a participatory democratic approach which is increasingly adopted in many countries around the world. The latter falls into the class of matching problems under preferences, where agents need to be matched to elements (tasks, roommates, jobs, etc.) based on their preferences.

In such concrete and societal problems, it is crucial to guarantee that the algorithms used to compute the collective decision are fair to the agents, in order to ensure confidence and participation in the system. The guarantee of fairness in collective decision making can be achieved via the justification of the final decision to satisfy a given appropriate fairness concept. This involves designing realistic and achievable fairness concepts, but also to explain that the final outcome is actually fair.

Important research questions remain on the design of adequate notions of fairness and their explanation for collective decision problems. The goal of this workshop is to bring together researchers from different communities in order to share insights on these topics and to progress towards a better understanding of fairness and its explanation in collective decision making. The focus will be on two specific topics: participatory budgeting and matchings under preferences. The main research questions we can investigate in these two settings are the following:

Schedule

The workshop will take place over two weeks from March 30th to April 10th at Institut Pascal (Orsay, France).

The global schedule of the two weeks is composed of:

• a global introduction and conclusion for the workshop,

• a description of GDR RADIA and a GDR invited talk,

• two transverse invited talks,

• four slots for participants’ short presentations,

• a doctoral consortium,

• a social event,

• two social dinners,

• two working blocks dedicated to specific topics:

  • Week A: participatory budgeting 

  • Week B: matching under preferences

Each working block is composed of 11 sessions of 1h30 structured as follows:

• one tutorial, given by an expert of the topic,

• a global discussion in order to identify interesting research questions and to form subgroups,

• two invited talks,

• five working sessions in subgroups and a last one dedicated to the writing of the report and preparation of the presentation of the subgroup,

• one final session where each subgroup presents its work to the whole audience.

The invited speakers are:

• Jiehua Chen (TU Wien),
• Ágnes Cseh (University of Bayreuth),
• Ulle Endriss (University of Amsterdam),
• Bettina Klaus (University of Lausanne),
• Jan Maly (WU Wien),
• Nicolas Maudet (Sorbonne Université),
• Dominik Peters (CNRS, Université Paris-Dauphine), and
• Piotr Skowron (University of Warsaw).

The global preliminary organization of the two weeks is presented below.

Global schedule of the two weeks