On the Optimal Size of Committees of Experts

What is the optimal size of expert committees? To address this question, I present a model of a committee of experts with career concerns. Each expert may observe an argument about the state of the world but be unsure about the argument's soundness. Experts may remain silent or compete for the opportunity to announce an argument. I show that experts become more reluctant to speak in larger committees. This effect is sufficiently strong to make small groups of experts optimal. At the same time, a small committee may be superior to an individual expert.