Multi-Winner Elections: What do we Elect Committees for?

Speaker(s)

Piotr Skowron

Affiliation

Google

Date

Dec. 17, 2015, 12:15 p.m.

Room

room 3320

Seminar

Seminar Games, Mechanisms, and Social Networks

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We present a brief overview of several interesting multi-winner election rules and we identify a broad natural class of multi-winner score-based rules (called committee-scoring rules), and we show that several existing interesting rules can be captured by this class. Within this class we identify the multi-winner analogues of the single-winner Plurality rule (one of the most popular single-winner rules used in practice), and we characterize this class axiomatically. 

In the second part of the talk we present a new model that describes the process of electing a group of representatives (e.g., a parliament) for a group of voters. In this model, called the voting committee model, the elected group of representatives runs a number of ballots to make final decisions regarding various issues. The satisfaction of voters comes from the final decisions made by the elected committee. Our results suggest that depending on a single-winner election system used by the committee to make these final decisions, different multi-winner election rules are most suitable for electing the committee.

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