竞争环境下存在规模经济的集团采购供应链协调

Coordinating a Group Purchasing Supply Chain under Economies of Scale and Competition

研究两个制造商通过一个集团采购组织(GPO)集中采购某种部件的集团采购问题,并考虑部件价格的数量折扣、各制造商产品的部分替代性。首先构建集中式决策、独立采购两种基准决策模型,分析集团采购的可行条件。然后,构建批发价格契约下的集团采购决策模型,分析规模经济性、竞争强度和部件价值等因素对于均衡结果的影响,并揭示制造商参与集团采购的激励问题。最后提出两种契约协调方案,并考察契约的适用性。研究发现:部件价值越高,竞争越激烈,集团采购越是可行;批发价格契约不仅会降低集团采购价值,还会降低制造商参与集团采购的积极性;收益共享契约只能在部分情形下协调供应链,而"会员费+佣金"的两部收费契约可实现完美供应链协调。

In the current context of variety and small batch production,group purchasing has been increasingly viewed as an effective tool to save cost and improve performance in manufacturing.Through group purchasing,manufacturers can realize economies of scale by aggregating their purchasing volume.However,in many cases,due to incentive misalignment,group purchasing may create less value than individual purchasing,which makes group purchasing infeasible.To study the value-creating and incentive issues with group purchasing,a supply chain that consists of one group purchasing organization(GPO)and two manufacturers competing in quantity is investigated.The GPO purchases a common component from vendors at a price given by aquantity discount function,and then provides the component for the manufacturers at a transfer price.The manufacturers further process the component to make imperfectly substitutable products.A two-stage Stackelberg game model is used to study the equilibrium decisions.In the first stage,the GPO sets a unified wholesale price of the component for the manufacturers.In the second stage,upon learning the wholesale price,each manufacturer decides his order quantity.The main work in this paper includes four parts.At first,two benchmark models are established to investigate the scenarios of centralized decision and individual purchasing,respectively,and the feasible condition of group purchasing is analyzed.Secondly,the decentralized decision model of group purchasing with wholesale price contracts is constructed,and by analyzing the impacts of economies of scale,competition intensity and component value on the equilibrium results,the incentive issues for the manufacturers to participate in group purchasing are raised.Thirdly,to address the incentive issues of group purchasing,two contracting schemes for supply chain coordination are presented,and their participation conditions are also checked to show their applicability.Finally,a numerical example is given to illuminate the impacts of the environment parameters on the quantities and the profits under different scenarios.The results indicate that group purchasing can be feasible relative to individual purchasing only under certain conditions,especially when the component value is higher or the competition is more intense.Group purchasing with wholesale price contracts will not only decrease the value of group purchasing,but also reduce the motivation of the manufacturers to participate in group purchasing,thus they make group purchasing more difficult to be feasible.Although a revenue sharing contracting scheme can achieve the first best value of group purchasing,it cannot satisfy the manufacturers' participation conditions in some cases,especially when the scale economy is lower and the competition is more intense.Instead,a two-part tariff contracting scheme,composed of a membership fee and a trade commission,can not only achieve the first best value of group purchasing,but also satisfy the manufacturers' participation conditions in all cases,thus it can coordinate the supply chain under group purchasing perfectly.In summary,the value of group purchasing under economies of scale and competition is investigated,which provides a new insight on the incentive issues of group purchasing.Moreover,contracting mechanisms are used to coordinate the supply chain under group purchasing,which offers a practical and a theoretical guidance to improve the value of group purchasing.