Going Public: Communication in Collective Decisions

2026-05-05

AI Summary

This study investigates how a principal can influence collective voting decisions by multiple agents under state uncertainty through strategic information disclosure. The principal may choose to reveal test-generated information either publicly or privately, and the analysis integrates Bayesian persuasion with cheap talk modeling alongside implementability considerations. The main contributions are threefold: first, it establishes that public communication weakly dominates private communication; second, it fully characterizes the optimal information disclosure structure in canonical linear-preference environments; and third, it provides necessary and sufficient conditions for public communication to strictly outperform private communication—specifically, when two agents whose preferences conflict with the principal’s are aligned with each other, public disclosure enables superior decision outcomes.

Abstract

A principal and $n\ge 2$ agents can launch a project if the principal proposes it and at least $k$ agents accept. Their individual payoffs from the project depend on an ex ante unknown state. The principal can conduct a test to learn about the state and then communicate her findings to the agents via cheap talk. This paper focuses on comparing two communication regimes: public and private messaging. We show that public messaging is weakly dominant: any outcome implementable under private messaging can also be implemented under public messaging. Moreover, in a canonical environment with linear payoffs, we characterize the principal's optimal test in each regime and show that public messaging can be strictly dominant if and only if there exist two agents who are the principal's conflicting allies.

Problem

• collective decisions
• cheap talk
• public messaging
• private messaging
• conflicting allies

Innovation

• public messaging
• private messaging
• information design
• cheap talk
• collective decision-making