The impossibility of unbiased judgement aggregation

F.K. Dietrich, C. List

Research output: Working paper / PreprintWorking paper

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All existing impossibility theorems on judgment aggregation over logically connected propositions have one of two restrictions: they either use a controversial systematicity
condition or apply only to special agendas of propositions with rich logical connections. An important open question is whether judgment aggregation faces any serious impossibilities without these restrictions. Here we prove the first impossibility
theorem without systematicity that applies to all standard agendas: there exists no judgment aggregation rule satisfying universal domain, collective rationality, anonymity and a new condition called unbiasedness. For many agendas, anonymity
can be weakened. Applied illustratively to (strict) preference aggregation represented in the judgment aggregation model, our result implies that every unbiased social welfare function with universal domain depends only on a single individual.
Original languageEnglish
Place of PublicationMaastricht
PublisherMETEOR, Maastricht University School of Business and Economics
Number of pages14
Publication statusPublished - 2005

Publication series

SeriesMETEOR Research Memorandum


  • judgment aggregation
  • logic
  • impossibility
  • May's neutrality

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