به اشتراک گذاری اطلاعات استراتژیک بین خرده فروشان رقیب در زنجیره تامین با قیمت عمده فروشی درونزا

This paper introduces a new motivation for information sharing in decentralized supply chains—as a mechanism to achieve truthful information sharing and to reduce signaling costs. We study a two-echelon supply chain with one manufacturer selling a homogenous product to n price-setting competing retailers. Each retailer has access to private information about the potential market demand, and the retailers have an ex-ante incentive to share this information with each other and to conceal the information from the manufacturer. However, without a mechanism that induces the retailers to truthful information exchange as their strategic choice, no information can be exchanged via pure communication (cheap talk). To overcome this obstacle, two signaling games are analyzed: in the first game, information is shared truthfully among the retailers; in the second game, information is also shared truthfully with the manufacturer. We show that under some conditions sharing information with the manufacturer results in a higher profit for the retailers.

The estimated cost of stockouts and inventory are astronomical, ranging from $14 billion for the food service industry (Troyer, 1996) to $30 billion for the grocery industry (Kurt Salmon Associates, 1993). A key initiative commonly mentioned as a possible remedy to lower these costs is information sharing among partners in supply chains. Recently, there has been more research that emphasizes the value of information sharing for operational effectiveness, such as improved inventory control, the elimination of the bullwhip effect and better matching of supply with demand (Chen, 1998, Aviv and Federgruen, 1998, Lee et al., 2000 and Cachon and Fisher, 2000 and Lee and Whang, 2000. An excellent survey of information sharing in supply chains can be found in Chen, 2003). Although better information usually improves the performance of a supply chain, when the supply chain is comprised of independent profit-maximizing firms, some key obstacles exist in creating an information-sharing agreement. First, in equilibrium, each firm must be better off sharing information than concealing it. Even when information sharing achieves the efficient outcome for the firms in the supply chain, in many cases there is a tension between efficiency and self-interest. This tension, which is a type of the famous prisoners' dilemma, can lead to an inefficient equilibrium, in which no-information is shared among competing firms (e.g. Gal-Or, 1985 and Li, 2002). Furthermore, when the accuracy of the shared information cannot be verified, firms in the supply chain must select truthful revelation of their private information as a strategic choice. For example, Solectron, a major electronics supplier, had $4.7 billion in excess component inventory because of the inflated forecasts provided by its customers (Engardio, 2001). When the supply chain is comprised of competing retailers, an additional challenge exists when a retailer shares information with his supplier, since once a retailer shares its private information with his supplier, its ability to control leakage of this information to his competitors is compromised. Wal-Mart, for example, announced that it would no longer share its sales data with outside companies like Information Resources, Inc. and ACNielsen, which paid Wal-Mart for the information and then sold it to other retailers (Hays, 2004). Two recent papers, Li and Zhang (2008) and Anand and Goyal (2009), study the effects of information leakage on the incentives to share information in a decentralized supply chain with downstream competition. The description above suggests that researchers view the complex structure of supply chains and the conflicting incentives of firms within the supply chain as obstacles to achieving information-sharing agreements. However, in this paper, we offer an alternative view: we assert that the same complex nature of a supply chain can provide firms with a tool to facilitate information-sharing agreements in settings of asymmetric information. To accomplish this, we model a two-echelon supply chain with downstream competition and present a new incentive for information sharing between the retailers and their mutual manufacturer—as a substitute for the signaling cost. When the retailers share hard information (information that cannot be manipulated) they have an ex-ante incentive to share private information about the future market demand and to conceal this information from their manufacturer. However, when the retailers share soft information (information for which the credibility of the shared information cannot be verified) each retailer has an incentive to manipulate the information; each retailer is better-off pretending that the market condition is better than his private signal suggests. Such information manipulation encourages the competing retailers to set a higher price, which benefits the manipulating retailer. As a result of this tendency to manipulate the shared information, the information-sharing agreement unravels; no information can be shared via means of cheap-talk. To overcome the problem of accountability and to allow the retailers to share information in a credible manner, we study two signaling games: in the first mechanism (referred to as the horizontal signaling game), each retailer incurs some cost related to his shared information. The retailers design the mechanism in such a way that the cost associated with the sent message signals that the retailers are accountable for the shared information. In this game, the retailers exchange information horizontally and conceal their private information from their manufacturer. As an alternative mechanism to the horizontal signaling game, we investigate the effect of including the manufacturer in the information club (we denote this option as the public signaling game) on the ability of the retailers to reach an information-sharing agreement. We demonstrate how the presence of the manufacturer in the information coalition affects the retailers' incentives to manipulate the shared information and consequently affects the signaling cost required to achieve truthtelling as the retailers' strategic choice. The presence of the manufacturer allows the retailers to expand the set of available mechanisms that result in truthtelling information sharing; that is, when the retailers share soft information, they benefit from the information-sharing agreement, but must incur some cost in order to be accountable for the shared information. The retailers can decide to share information with the manufacturer when the cost of reaching a truthtelling equilibrium under this setting is lower than the cost incurred in order to share information credibly when the manufacturer is not exposed to the shared information. The remainder of the paper is organized as follows. Section 2 discusses some of the relevant literature. Section 3 introduces the model, and Section 4 analyzes the incentives of the retailers to share information (horizontally and vertically) when the accuracy of the information can be verified. Section 5 relaxes the assumption that information is exchanged truthfully and examines the incentives of the retailers to truthfully exchange their private information in the presence of the manufacturer and in the absence of the manufacturer from the information club. Section 6 analyzes the two signaling games that result in truthtelling as the retailers' strategic choice. We conclude and offer future research path in Section 7.

Although information sharing can increase efficiency, independent firms endowed with private information often face a major challenge in adopting a scheme that induces truthtelling information sharing. In this paper, we introduce a new motivation for information sharing between a set of retailers and their mutual manufacturer—as a substitute for signaling cost. We present a novel model in which a set of competing retailers search for a mechanism to share their private demand information. The first option we consider is the retailers engaging in a signaling game. As an alternative mechanism, we examine the effect of including the manufacturer in the information club on the ability of the retailers to share information. We demonstrate that sharing information with the manufacturer affects the incentives of the retailers to manipulate the shared information; as a result, under some conditions, the retailers can reach an information sharing equilibrium at a lower cost. The model we present can be viewed as an example of a more general idea: by carefully including or excluding firms in the supply chain from the information club, the firms in the supply chain can change their signaling costs and reach an information exchange agreement for lower signaling costs. Further research in this area can evolve in several directions: the first involves generalizing the model to different types of competition and private information. For example, one can consider a set of retailers who compete by setting quantities with private cost information. As discussed in Section 4, it is agreed among researchers that the retailers in this setting wish to share this private cost information (e.g. Gal-Or, 1985). However, without a commitment mechanism, each retailer will be tempted to report low production costs (Ziv, 1993) in order to induce the competing retailer to produce less quantity of the product. A possible mechanism to induce truthful information sharing in this case is to share the private cost information with the manufacturer as well; reporting low production costs will result in a high wholesale price; hence, the incentives of a retailer to mis-report his true production costs can be balanced when the manufacturer is exposed to this information. Another possible way to extend our basic model is to assume that a retailer's decision to share his information publicly or horizontally is made after observing his private information. In the current model, we compare two settings: in the first, all retailers share their demand information horizontally; and in the second setting, all retailers share their demand information publicly. Thus, an important assumption in our modeling approach is that the decision to include the manufacturer (or not) in the information club is made ex-ante prior to observing the signal realization. As an alternative, we can adopt a different approach in which each retailer first observes his demand realization and only then decides if he wishes to share this information horizontally or publicly. The view of information sharing as a cost can also have implications for anti-trust regulation. Several economists (Kühn and Vives, 1995; Kühn, 2001; Motta, 2004) have recently argued that inferring collusion from market data is virtually impossible. Consequently, most competition authorities around the world have adopted the so-called parallelism plus rule. This policy allows the prosecution of collusive behavior only in cases where suspicion can be supported by hard evidence of facilitating practices, such as information exchange. Based on this view, Kühn (2001) has suggested that the information exchange of costs or demand should be considered to be an illegal restriction of the competition if the competition authorities demonstrate that no significant efficiency gains can be expected. However, based on the possible view of information sharing as a cost, we suggest that the gains from information sharing should be examined based on what we define as the total effect of information sharing on the supply chain. Although the direct effect of information sharing can result in losses for the sender of the information (in our model a retailer sharing information with his manufacturer) the total effect of this information sharing is positive since it enables the retailers to exchange information as well.