Speaker: Matthew Ryan (AUT)
Date, Time and Venue: Thursday, 26 October 2017, 2:00-3:00 pm, room 260-323 [Business School Building, Level 3]
Title: The Condorcet Jury Theorem: An Introduction
Abstract: Back in August, Simona Fabrizi presented her work with Addison Pan on the so-called “Jury Paradox”. The present talk provides an introduction to some of the background literature on group decision-making. The “Condorcet Jury Theorem” is an 18th century result due to the Marquis de Condorcet, which anticipates modern notions of the wisdom of crowds. It is also important in political theory as a rationale for democratic decision-making. The theorem asserts that (under suitable conditions) a group of relatively uninformed voters will make better decisions by majority rule than a single expert deciding unilaterally, provided the group is large enough. We introduce Condorcet’s result and its limitations, as well as a few extensions. Condorcet assumed “sincere” voting, while the modern research on group choice requires that votes be cast “rationally” – that is, the profile of votes should be an equilibrium (in the sense of Harsanyi) of the voting game. It is well-known that sincere voting need not be rational in this sense. Does the essence of the Jury Theorem survive strategic voting? Come along and find out!