Investment decisions and coordination problems in a market with network externalities: An experimental study

We study decision-making and the associated coordination problems in an experimental setting with network externalities. Subjects decide simultaneously in every round how much to invest out of a fixed endowment; the gain from an investment increases with total investment, so that an investment is profitable iff total investment exceeds a critical mass. The game has multiple, Pareto-ranked equilibria; we find that whether first-round total investment reaches critical mass predicts convergence towards the Pareto optimal full-investment equilibrium. Moreover, first-round investments and equilibrium convergence vary with critical mass and group size in a complex way that is explicable by subtle effects of strategic uncertainty on decision making.