DOES DUAL SOURCING LOWER PROCUREMENT COSTS?*
利用战术导弹面板数据，研究发现双重采购并非因成本降低失败而采用，更多是在现有供应商出现质量问题或难以形成默契合谋时使用；纠正选择偏差后，双重采购显著降低了政府采购成本。
U.S. defense policy encourages the use of dual sourcing to reduce government procurement costs, but recent theoretical work raises doubts about the benefits of this policy. I study the determinants of dual sourcing and its effects on government procurement costs using a panel dataset of tactical missiles. I find dual sourcing is not driven by failures to reduce costs; instead, it is used more often after incumbent suppliers demonstrate quality control problems, and in settings where tacit collusion is likely to be difficult. After correcting for selection bias, dual sourcing is found to reduce government procurement costs significantly.