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A Model of Public Consultation: Why is Binary Communication so Common?


  •  Corrresponding author: Kohei Kawamura, School of Economics, University of Edinburgh, Edinburgh, EH8 9JT, UK. E-mail:

  • I thank Vincent Crawford, Wouter Dessein, Mathias Dewatripont, Navin Kartik, David Myatt, Marco Ottaviani, Andrea Patacconi, John Quah, Jose V. Rodríguez Mora, József Sákovics, Joel Sobel, Koichi Tadenuma, an anonymous referee and seminar participants at Aberdeen, Edinburgh, Oxford and Southampton for helpful discussions and comments. I am particularly grateful to James Malcomson and Margaret Meyer for their guidance. All errors are my own.


This article studies information transmission between multiple agents with heterogeneous preferences and a welfare maximising decision maker who chooses the quality or quantity of a public good (e.g. size of a public project; pace of lectures in a classroom; government regulation) that is consumed by all of them. As the number of agents becomes larger, the quality of information transmission diminishes. The use of binary messages (e.g. ‘yes or no’ ) is shown to be a robust mode of communication even when the preferences and policy space are non-binary.