How should a principal reward and support agents when firm performance is characterized by success or failure?

Principal-agent models with multiple agents typically assume that the principal wishes to maximize the sum of the agents' achievements (net of the rewards paid to them). But in many settings, like R&D, all that the principal "needs" is that at least one agent will be "successful." We identify settings where the principal actually wants agents to refrain from exerting high effort in order to save expected compensation.