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The impossibility of unbiased judgment aggregation

Dietrich, Franz and List, Christian ORCID: 0000-0003-1627-800X (2007) The impossibility of unbiased judgment aggregation. . Department of Government, London School of Economics and Political Science, London, UK. (Submitted)

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Standard impossibility theorems on judgment aggregation over logically connected propositions either use a controversial systematicity condition or apply only to agen- das of propositions with rich logical connections. Are there any serious impossibilities without these restrictions? We prove an impossibility theorem without systematicity that applies to most standard agendas: Every judgment aggregation function (with rational inputs and outputs) satisfying a condition called unbiasedness is dictatorial (or e¤ectively dictatorial if we remove one of the agenda conditions). Our agenda conditions are tight. Applied illustratively to (strict) preference aggregation repres- ented in our model, the result implies that every unbiased social welfare function with universal domain is e¤ectively dictatorial.

Item Type: Monograph (Working Paper)
Official URL:
Additional Information: © 2007 Franz Dietrich and Christian List
Divisions: Government
Philosophy, Logic and Scientific Method
Subjects: B Philosophy. Psychology. Religion > BC Logic
Date Deposited: 29 Jul 2008 08:33
Last Modified: 15 Sep 2023 23:08

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