In public procurement, most contracts are renegotiated ex post and involve subcontractors. We examine whether there is a causal link between subcontractor use and the incidence of change orders to amend the original scope of a project. Since subcontracting is likely related to unobserved project complexity, we use a novel IV, the predicted level of subcontracting from a method modeled after Christakis et al. (2010), to estimate the likelihood of renegotiation. The results establish that subcontractors are associated with an increased likelihood of change orders as well as a higher dollar amount renegotiated.

中文翻译：

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分包和采购合同中变更单的发生率

在公共采购中，大多数合同都是事后重新谈判并涉及分包商。我们检查分包商的使用与修改项目原始范围的变更单的发生率之间是否存在因果关系。由于分包可能与未观察到的项目复杂性有关，因此我们使用了一种新颖的 IV，即根据 Christakis 等人的建模方法预测的分包水平。(2010)，估计重新谈判的可能性。结果表明，分包商与变更单的可能性增加以及重新谈判的美元金额增加有关。