Judgment aggregation and agenda manipulation

Dietrich, Franz (2013): Judgment aggregation and agenda manipulation. Published in: Games and Economic Behavior No. 95 (January 2016): pp. 113-136.

Abstract

When individual judgments ('yes' or 'no') on some propositions are aggregated into collective judgments, outcomes may be sensitive to the choice of propositions under consideration (the 'agenda'). Such agenda-sensitivity opens the door to manipulation by agenda setters. I define three types of agenda-insensitivity ('basic', 'full', and 'focal') and for each type axiomatically characterize the aggregation procedures satisfying it. Two axioms turn out to be central for agenda-insensitivity: the familiar independence axiom, requiring propositionwise aggregation, and the axiom of implicit consensus preservation, requiring the respect of any (possibly implicit) consensus. As the paper's second contribution, I prove a new impossibility theorem whereby these two axioms imply dictatorial aggregation for almost all agendas.

• Item Type: MPRA Paper
• Language: English
• Keywords: judgment aggregation, agenda manipulation, impossibility theorems
• Subjects: D - Microeconomics > D7 - Analysis of Collective Decision-Making > D70 - General; D - Microeconomics > D7 - Analysis of Collective Decision-Making > D71 - Social Choice ; Clubs ; Committees ; Associations; D - Microeconomics > D7 - Analysis of Collective Decision-Making > D72 - Political Processes: Rent-Seeking, Lobbying, Elections, Legislatures, and Voting Behavior

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