On disclosure policy in contests with stochastic entry

We study how a contest organizer who seeks to maximize participant effort should disclose the information on the actual number of contestants in an imperfectly discriminatory contest with stochastic entry. When each potential contestant has a fixed probability of entering the contest, the optimal disclosure policy depends crucially on the properties of the characteristic function H(?)=f(?)/f ^??(?), where f(?) is the impact function. The contest organizer prefers full disclosure (full concealment) if H(?) is strictly concave (strictly convex). However, the expected equilibrium effort is independent of the prevailing information disclosure policy if a linear H(?) (Tullock Contest) applies.