考虑承包商过度自信和时间价值的激励契约研究

Research on incentive contract considering contractor′s overconfidence and time value

鉴于传统委托代理模型的分析框架未能充分反映承包商在工程项目中实际活动的现实,本文引入拓展的委托代理模型,同时考虑到承包商在施工过程中会存在过度自信倾向和时间价值,分析非对称信息情形下业主和承包商的利益博弈,探究承包商过度自信和时间价值对双方最优决策的影响。其中,承包商过度自信表现为低估项目风险,时间价值表征预期机会收益。本文进一步分析契约并与建立的两个基准契约模型比较,研究业主与承包商之间的最优激励契约设计问题。仿真结果表明考虑承包商过度自信和时间价值的激励契约起着降低业主期望总成本的作用,对于项目业主而言,识别承包商的类型并选择合适的风险分担系数可以有效激励承包商努力工作,实现双方利益目标一致。研究结果对业主设计最优激励契约具有一定的借鉴意义。

In the special period of normalized epidemic prevention and control,the effective management of the time and cost is directly related to the economic and social benefits of owners in the face of the increasingly fierce competition environment in the engineering field.In addition,the information asymmetry between the owner and the contractor brings the contractor moral hazard.Therefore,how owners design incentive contracts to alleviate the conflict of interest between the two parties with inconsistent goals has become one of the most important and urgent issues in project management.In order to solve the problem of designing incentive contract between the owner and the contractor,the overconfidence tendency and time value of the contractor are incorporated into the extended principal-agent model here.The influence of the psychological and behavioral biases of the contractor on the decision-making of the owner and the contractor is explored more comprehensively so that the incentive contract made by the owner is closer to the reality.Due to the complexity and uncertainty of the project,the contractor problem in the actual project involves the optimization of the scheduling of project activities.Targeting the fact that the analysis framework of traditional principal-agent model cannot fully reflect the project scheduling problem from an agency perspective,the extended principal-agent model is established,more in line with the actual activities of the contractor in the process of project.Besides,traditional theoretical assumptions often regard the agents as completely rational people,which often cannot effectively explain the practical problems and weaken the effect of theory guiding practice.The contractors have overconfidence tendency and time value in the process of construction.So,how do these psychological and behavioral characteristics of the contractor influence the design of the owner′s incentive contract,and how can the owner recruit these characteristics to design the appropriate incentive contract?Both of them are taken into consideration in the extended principal-agent model and the game model between the owner and the contractor is established under the condition of asymmetric information to analyze the influence of the contractor′s overconfidence and time value on the optimal decision of both parties.Overconfidence is manifested in underestimating the project risk,like large engineering contractors having high confidence in their own information and technology mastery,external risk control ability and so on.The time value represents the expected opportunity return,such as time gains from contractors completing projects ahead of schedule and undertaking new projects.In order to measure the consistency of the interests between the owner and the contractor and the improvement efficiency of total project cost under the contract,two benchmark contract models are established.One is the optimal incentive contract with symmetric information.The other is the optimal incentive contract when the contractor has no overconfidence and time value.In the meanwhile,two evaluation indexes of contract are proposed,including the evaluation indexes of contract consistencyηand contract efficiencyτ.ηreflects the degree to which the incentive contract[OP1]with asymmetric information can achieve the consistency of the goal between the contractor and the owner,andτreflects the improvement efficiency of the incentive contract[OP1]with asymmetric information on the owner′s total project cost.The optimal incentive contract design between the owner and the contractor is studied by comparing this contract with the two benchmark contract.The theoretical research and simulation results are as follows:1)The incentive contract considering contractor′s overconfidence and time value plays a role in reducing the owner′s expected total cost.2)The higher the overconfidence of the contractor,the higher the consistency of the contract and the higher the efficiency of cost improvement,that is to say,the goal consistency between the contractor and the owner is increasing.However,the increase of unit time value cannot improve contract consistency.Thus,owners should choose more qualified and competent contractors who are more confident of their ability to deal with uncertain risks of the project.3)Total project cost,total activities cost and project duration do not necessarily decrease monotonously with the increase of incentive coefficient,and may remain unchanged or increase.Therefore,the owner needs to balance the incentive and risk to the contractor.4)There is no obvious monotonic relation between the optimal incentive coefficient and contractor′s overconfidence or unit time value.Therefore,identifying the type of the contractor and determining appropriate risk sharing ratio can effectively motivate contractor to work hard and achieve the common interests of both sides.Collectively,the results can be used as a reference in the design of optimal incentive contract.