Increasing marginal costs and satiation in the private provision of public goods: group size and optimality revisited

It is widely recognized that the degree of inefficiency in the voluntary provision of a public good increases with the group size of an economy. However, we find that only a slight modification in the conventional assumptions gives rise to a profound difference in outcome. In particular, we show that there is a case where the Nash equilibrium provision and the efficient provision will converge as the size of an economy grows. To show this, we assume individuals face increasing marginal cost of voluntary provision and their preference function has a finite satiety point.