Robust Voting under Uncertainty
Abstract:
This paper proposes normative consequentialist criteria for voting rules under Knightian uncertainty about individual preferences to characterize a weighted majority rule (WMR). The criteria stress the significance of responsiveness, i.e., the probability that the social outcome coincides with the realized individual preferences. A voting rule is said to be robust if, for any probability distribution of preferences, responsiveness of at least one individual is greater than one-half. Our main result establishes that a voting rule is robust if and only if it is a WMR without ties. This characterization of a WMR avoiding the worst possible outcomes complements the well-known characterization of a WMR achieving the optimal outcomes, i.e., efficiency regarding responsiveness.
Report No.: | HIAS-E-60 |
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Author(s): | Satoshi Nakada(a) Shmuel Nitzan(b), (c) Takashi Ui(a) |
Affiliation: | (a) Graduate School of Economics, Hitotsubashi University (b) Department of Economics, Bar-Ilan University (c) Hitotsubashi Institute for Advanced Study, Hitotsubashi University |
Issued Date: | December 2017 |
Keywords: | majority rule, weighted majority rule, responsiveness, Knightian uncertainty |
JEL: | D71, D81 |
Links: | PDF, HERMES-IR, RePEc |