Population uncertainty in contests

We study contests where the set of players is a random variable. If it is known for certain that there will be at least one participant, then aggregate contest expenditure in equilibrium is strictly lower in a contest with population uncertainty than in a non-uncertain contest with the same expected number of players. This suggests an explanation of, for example, why empirical studies show rent-seeking expenditures to be much lower than predicted by other theories. Copyright Springer-Verlag Berlin/Heidelberg 2006