中文摘要
标准采购模型假设买方在采购时已知商品质量；然而在许多情形下，质量只有在交易完成很久之后才能得知。我们研究这样一类采购问题：买方对所供应商品的估值直接取决于其质量，而该质量对买方而言不可验证且不可观测。对于一大类采购问题，我们识别出使买方预期收益与社会剩余的任意加权平均值最大化的采购机制。最优机制可通过一种限制卖方仅在特定区间内提交报价的拍卖来实施。（JEL D44, D82, H57, L15）
Abstract
Standard procurement models assume that the buyer knows the quality of the good at the time of procurement; however, in many settings, the quality is learned only long after the transaction. We study procurement problems in which the buyer's valuation of the supplied good depends directly on its quality, which is unverifiable and unobservable to the buyer. For a broad class of procurement problems, we identify procurement mechanisms maximizing any weighted average of the buyer's expected payoff and social surplus. The optimal mechanism can be implemented via an auction that restricts sellers to submitting bids within specific intervals. (JEL D44, D82, H57, L15)