Spreading Information via Social Networks: An Irrelevance Result

An informed planner wishes to spread information among a group of agents in order to induce efficient coordination -- say the adoption of a new technology with positive externalities. The agents are connected via a social network. The planner informs a seed and then the information spreads via the network. While the structure of the network affects the rate of diffusion, we show that the rate of adoption is the same for all acyclic networks.