Rent-seeking contest when the prize increases with aggregate efforts

The objective of this article is to investigate contests in which efforts are productive. Tullock's standard rent-seeking model is extended by making the rent itself increase with the aggregate efforts. A positive externality is thereby introduced into the contest, because a contender's private effort in quest of the rent generates a benefit for other contenders. Coupled with a negative externality presented in the standard rent-seeking model, the net effect on the social efficiency of the contest is a priori ambiguous. It is shown that the extended contest generates socially wasteful, excessive aggregate efforts.