不完全契约视角下PPP项目再谈判的效率改进研究

Public Private Partnerships (PPP) have been popular as an innovative public procurement approach around the world. PPP contracts are usually extremely incomplete, so renegotiations are widely used to deal with contingencies. Practice has proved that renegotiations can provide flexibility for governments and contractors, but also cause significant efficiency losses. This research focuses on three efficiency problems with regard to the renegotiation of PPP projects. (1) The transaction costs of renegotiation are evaluated and their influencing variables are investigated, then an optimization model of transaction costs is developed. (2) The reference points effect of renegotiation is analyzed focusing on formation mechanisms, and verified through economic experiments of renegotiations in PPP projects. (3) The impact on Value for Money (VFM) of renegotiations is assessed qualitatively emphasizing the difference of renegotiation events, and also evaluated quantitatively considering the risk aversion of local governments. This research solves three critical decision-making problems in renegotiations, which are when to use renegotiation, when to use self-enforcement and when to use early termination. The output of this research provides theory basis for efficiency improvements of renegotiations in PPP projects.

政府与社会资本合作模式（PPP）作为一种创新的公共产品采购方式，在国内外得到了广泛应用。由于PPP特许经营合同的不完全性，再谈判被大量用来解决合同未尽事宜。实践证明，再谈判为政府和私营方提供了灵活性，但是也导致了很严重的效率损失。本研究从三个方面深入分析了再谈判的效率问题。（1）再谈判的交易成本：评估再谈判的交易成本，分析其影响变量，并构建交易成本优化模型；（2）再谈判的参照点效应：分析参照点效应的形成机理，设计基于PPP现实情境的再谈判经济学实验，验证参照点效应并提出应对策略；（3）再谈判对物有所值（VFM）的影响：考虑不同的再谈判事件的差异定性评估对VFM的影响，然后考虑政府的风险厌恶系数定量评估对VFM的影响。本研究解决了PPP项目再谈判中政府和私营方三个重要的决策问题：何时可以发起再谈判；何时应该采取自我约束；何时应该提前终止。研究成果将会为PPP项目再谈判的效率改进提供理论依据。

政府与社会资本合作（PPP）模式自2014年在我国大力推广以来，大量的项目由于操作不规范而面临整改。合同再谈判作为整改的主要手段，对我国PPP模式的健康发展有至关重要的作用。本研究基于不完全契约理论，从以下三个方面研究了PPP项目再谈判的效率评估和改进问题：（1）对相关文献进行了系统综述，识别PPP项目效率的影响机制；（2）建构PPP项目再谈判的理论模型，评估其对经济价值和公共价值的影响；（3）改进PPP项目的治理体系，降低再谈判带来的效率损失。本研究为合理开展PPP项目再谈判工作提供了理论支持和实证经验，有效地减少了缔约双方的机会主义行为，保护了PPP项目的公共价值。