On obvious strategy-proofness and single-peakedness

Authors: R. Pablo Arribillaga, Jordi Massó and Alejandro Neme

Journal of Economic Theory, Vol. 186, 104992, March, 2020

We characterize the set of all obviously strategy-proof and onto social choice functions on the domain of single-peaked preferences. Since obvious strategy-proofness implies strategy-proofness, and the set of strategy-proof and onto social choice functions on this domain coincides with the class of generalized median voter schemes, we focus on this class. We identify a condition on generalized median voter schemes for which the following characterization holds. A generalized median voter scheme is obviously strategy-proof if and only if it satisfies the increasing intersection property. Our proof is constructive; for each generalized median voter scheme that satisfies the increasing intersection property we define an extensive game form that implements it in obviously dominant strategies.

This paper originally appeared as Barcelona GSE Working Paper 1122