中文摘要
美国政府在公路和桥梁方面的大部分支出通过“按量计价”采购拍卖完成；在此类拍卖中，私营建筑企业针对完成项目所需的每一种材料分别提交单位价格投标。利用马萨诸塞州交通运输部（MassDOT）实施的桥梁维护项目数据，我们提供的证据表明，在这一情境下，企业的投标行为与风险厌恶条件下的最优偏斜报价相符：企业通过对不确定性更大的项目分项报出更低的单位价格来限制其风险敞口。我们估计了每场拍卖中的不确定性程度，以及投标者私人成本和风险厌恶程度的分布。通过模拟反事实情形下的均衡分项报价，我们估计了项目支出中由风险导致的比例，并评估了政策制定者正在考虑的拍卖机制。我们发现，与总价拍卖相比，按量计价拍卖能够大幅节省成本，并说明了如何利用我们的框架评估其他拍卖设计。
Abstract
Most U.S. government spending on highways and bridges is done through “scaling” procurement auctions, in which private construction firms submit unit price bids for each piece of material required to complete a project. Using data on bridge maintenance projects undertaken by the Massachusetts Department of Transportation (MassDOT), we present evidence that firm bidding behavior in this context is consistent with optimal skewing under risk aversion: firms limit their risk exposure by placing lower unit bids on items with greater uncertainty. We estimate the amount of uncertainty in each auction, and the distribution of bidders' private costs and risk aversion. Simulating equilibrium item‐level bids under counterfactual settings, we estimate the fraction of project spending that is due to risk and evaluate auction mechanisms under consideration by policymakers. We find that scaling auctions provide substantial savings relative to lump sum auctions and show how our framework can be used to evaluate alternative auction designs.