The goal of the present paper is to analyze the optimal targeting strategies of a planner (say a monopolist) who aims to increase the aggregate action of agents (consumers' purchase). Agents are embedded in a social network and their actions influence each other. Actions are complements,...

A hierarchical structure is a widespread organizational form in many areas. My aim in this paper is to provide a rationale for this fact based on two premises. First, a group organizes itself so as to achieve efficient coordination. Second, efficient coordination is achieved only if subgroups as...