Real-effort experiments are frequently used when examining a response to incentives. For any particular real-effort task to be well-suited for such an exercise, subjects' cost for exerting effort must, for the range of incentives considered, result in an interior effort choice. The popular...

A large and growing literature has demonstrated that explicit incentives, such as enforceable contracts, can lead agents to withhold effort. We investigate when this behavioral result arises. In an extensive laboratory experiment, we find that imposing control through an enforceable contract is...