Strategy-proof judgment aggregation

Franz Dietrich and Christian List

LSE Research Online Documents on Economics from London School of Economics and Political Science, LSE Library

Abstract: In the theory of judgment aggregation on logically connected propositions, an important question remains open: Which aggregation rules are manipulable and which are strategy-proof? We define manipulability and strategy-proofness in judgment aggregation, characterize all strategy-proof aggregation rules, and prove an impossibility theorem similar to the Gibbard-Satterthwaite theorem. Among other escape-routes from the impossibility, we discuss weakening strategy-proofness itself. Comparing two prominent aggregation rules, we show that conclusion-based voting is strategy-proof, but generates incomplete judgments, while premise-based voting is only strategy-proof for "reason-oriented" individuals. Surprisingly, for "outcome-oriented" individuals, the two rules are strategically equivalent, generating identical judgments in equilibrium. Our results introduce game-theoretic considerations into judgment aggregation and have implications for debates on deliberative democracy.

Keywords: Judgment aggregation; strategy-proofness; logic; Gibbard-Satterthwaite theorem (search for similar items in EconPapers)
JEL-codes: J1 (search for similar items in EconPapers)
Pages: 23 pages
Date: 2005-08
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

Downloads: (external link)
http://eprints.lse.ac.uk/19299/ Open access version. (application/pdf)

Related works:
Journal Article: STRATEGY-PROOF JUDGMENT AGGREGATION* (2007)
Working Paper: Strategy-proof judgment aggregation (2007)
Working Paper: Strategy-proof judgment aggregation (2005)
Working Paper: Strategy-proof judgment aggregation (2005)
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Persistent link: https://EconPapers.repec.org/RePEc:ehl:lserod:19299

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