We study the distribution of multiple homogeneous items to multiple agents with unit demand. Monetary transfer is not allowed and the allocation of the items can only depend on the informative signals that are manipulable by costly and wasteful efforts. Examples of such scenarios include grant allocation, college admission, lobbying and affordable housing. We show that the welfare-maximizing mechanism takes the form of a contest and characterize it. We apply our characterizations to study large contests. When the number of agents is large compared to item(s), the format of the optimal contest converges to winner-takes-all, but principal's payoff does not. When both the number of items and agents are large, allocation is randomized to middle types to induce no effort under optimal contest, which weakly decreases effort for all higher types.

翻译：我们研究在单位需求下将多个同质物品分配给多个代理人的问题。货币转移不被允许，物品分配仅能依赖于代理人通过耗费成本且无效率的努力操纵的信息信号。此类场景的例子包括科研经费分配、大学录取、游说活动及经济适用房分配。我们证明，社会福利最大化的机制采取竞赛形式，并对其进行了刻画。我们将这些特征应用于大规模竞赛的研究。当代理人数量相对于物品数量较大时，最优竞赛形式趋近于"赢家通吃"，但委托人的收益并不收敛。当物品与代理人的数量均较大时，中间类型的分配将被随机化，以在最优竞赛下诱导零努力水平，从而使得所有更高类型的努力程度弱化下降。