Managing Persuasion Robustly: The Optimality of Quota Rules

We study a sender-receiver model in which the receiver can commit to a decision rule before the sender determines the information policy. The decision rule can depend on the information structure chosen by the sender and the realized signals. This framework captures applications where a decision-maker (the receiver) seeks advice from an interested party (the sender). In these applications, the receiver frequently faces uncertainty regarding the sender's preferences and the set of feasible information structures. Consequently, we adopt a unified robust analysis framework that includes the max-min utility, the min-max regret, and the min-max competitive ratio as special cases. We show that the optimal decision rule is always a quota rule.