Most economic models are based on the self-interest hypothesis that assumes that all people are exclusively motivated by their material self-interest. In recent years experimental economists have gathered overwhelming evidence that systematically refutes the self-interest hypothesis and suggests...

We show that concerns for fairness may have dramatic consequences for the optimal provision of incentives in a moral hazard context. Incentive contracts that are optimal when there are only selfish actors become inferior when some agents are concerned about fairness. Conversely, contracts that...

We show experimentally that fairness concerns may have a decisive impact on both the actual and the optimal choice of contracts in a moral hazard context. Explicit incentive contracts that are optimal according to self-interest theory become inferior when some agents value fairness. Conversely,...

For the procurement of complex goods the early exchange of information is important to avoid costly renegotiation. If the buyer can specify the main characteristics of possible design improvements in a complete contingent contract, a scoring auction implements the efficient allocation. If this...

We consider a multi-dimensional procurement problem in which sellers have private information about their costs and about a possible design flaw. The information about the design flaw is necessarily correlated. We solve for the optimal Bayesian procurement mechanism that implements the efficient...

For the procurement of complex goods the early exchange of information is important to avoid costly renegotiation ex post. We show that this is achieved by bilateral negotiations but not by auctions. Negotiations strictly outperforms auctions if sellers are likely to have superior information...