Multi-tasking, quality and pay for performance
研究了医疗服务购买方与提供方之间的最优契约设计，当质量有两个维度（一个可验证、一个不可验证）且两者可能替代或互补时，将价格设为可验证质量维度的边际收益可能是最优的。
We present a model of optimal contracting between a purchaser and a provider of health services when quality has two dimensions. We assume that: (i) the provider is (at least to some extent) altruistic; (ii) one dimension of quality is verifiable (dimension 1) and one dimension is not verifiable (dimension 2); (iii) the two quality dimensions can be either substitutes or complements. Our main result is that setting the price equal to the marginal benefit of the verifiable quality dimension can be optimal even if the two quality dimensions are substitutes.