We consider contests where participants have private information about their ability and the contest designer can manipulate the values of different prizes to influence effort. We study the effect on effort of two different interventions: increase in the value of prizes and increase in competition (transfer of value from worse to better prizes). We identify two natural sufficient conditions on the distribution of abilities in the population under which both interventions have opposite effects on effort. More precisely, we find that if the density of agents is decreasing in ability so that unproductive agents are more likely than productive agents, the two interventions encourage effort. And if this density is monotone increasing in ability, the interventions discourage effort. We discuss applications to the design of optimal contests in three different environments, including the design of grading contests. Assuming the value of a grade is determined by the information it reveals about the agent's ability, we establish a link between the informativeness of a grading scheme and the effort induced by it.

翻译：我们考虑参与者拥有关于自身能力的私人信息，且竞赛设计者可通过调整不同奖项价值来影响努力的竞赛。我们研究了两种不同干预措施对努力的影响：提高奖项价值与增强竞争（将价值从较差奖项转移至较优奖项）。我们识别出人口能力分布的两个自然充分条件，在这两种条件下，两种干预措施对努力产生相反效应。更精确地，我们发现若代理人密度随能力递减（即低生产率代理人比高生产率代理人更常见），则两种干预措施会激励努力；若该密度随能力单调递增，则干预措施会抑制努力。我们讨论了三种不同环境（包括评分竞赛设计）中最优竞赛设计的应用。假设成绩价值由其揭示代理人能力的信息量决定，我们建立了评分方案的信息含量与其所诱发的努力水平之间的联系。