Managing inventory with two suppliers under yield uncertainty and risk aversion

In this paper, we consider a single-product single-period inventory model in which the retailer can source from two suppliers. The primary supplier is cheaper but unreliable in the sense that it generates supply yield uncertainty, whereas the secondary supplier is perfectly reliable but more expensive. The reliable supplier's capacity is fixed and the retailer cannot order more than the quantity reserved in advance. We study the problem in the context of a risk-averse retailer who has to determine the optimal order quantity from the primary supplier and the optimal reserved quantity from the secondary supplier. We develop the model in the perspective of a low risk averse retailer and quantify the risk via an exponential utility function. We show by numerical experiments how the resulting dual sourcing strategies differ from those obtained in the risk-neutral analysis. We also examine the sensitivity of some model-parameters on the optimal decisions.     

基于改进TOPSIS法的供应商选择模型研究

为有效地帮助企业快速找到合适的供应商合作伙伴,采用直觉模糊集、评分函数等方法对TOPSIS评估法进行优化,并以此为基础建立了一种供应商选择模型。首先,采集和评估供应商的产品质量、产品价格、产品交货的可靠性、供应位置、财务情况、库存水平、劳资关系、发展能力和技术能力等相关信息,由专家给出主观评估信息,汇总为综合属性值;然后,通过直觉模糊熵确定各评估指标的权重;最后,综合考虑供应商选择决策过程中的多个目标和标准,应用改进TOPSIS法的对供应商进行分类选择。结果显示,基于改进TOPSIS法的供应商选择模型能够较准确地反映出各供应商的真实水平和对企业的潜在价值,可以有效地解决不确定条件下对供应商的选择问题,提高了供应商选择结果的可靠性。改进后的模型简便易行,具有良好的稳定性,对于合理制定企业供应商选择标准以及进一步优化决策模型具有一定的借鉴意义。     

Upstream Capacity Constraint and the Preservation of Monopoly Power in Private Bilateral Contracting

This article presents a model of private vertical contracting with a capacity constrained monopolistic supplier. I consider ‘full capacity beliefs’ that are consistent with an upstream capacity constraint and are ‘wary’ when the constraint is tight or production is costless. I show that, facing a capacity constraint, the supplier may preserve its monopoly power in equilibrium. This result stands in sharp contrast to the standard result that the supplier cannot preserve its monopoly power, which holds under the usual implicit assumption of an infinite production capacity.     

Parallel sourcing and supplier performance in the Japanese automobile industry

Japanese auto makers are reported to enjoy high supplier performance through long-term relationships, specific investments, and sole sourcing. Quality management consultants in the U.S. have been strongly advocating adoption of these practices. But economic and management theorists would predict that the combination of a high level of relationship-specific investments and sole sourcing will lead to problems with supplier performance. In fact the Japanese auto makers use a hybrid form of organization we term parallel sourcing. We present a transaction costs model that shows how parallel sourcing provides incentives for supplier performance associated with multiple sourcing while preserving claimed benefits of sole sourcing.     

The multiple levels of trust when selecting suppliers – Insights from an automobile manufacturer

In this study, we aim to develop a framework for the concept of trust prior to forming relationships when selecting suppliers. Entering a relationship with a supplier for an extended period requires a certain level of trust in different facets (such as interpersonal relationships, continuous supply, and compatibilities). In situations in which suppliers need to enter into relationships characterized by high uncertainties, such as sourcing for high technology, trust becomes even more important. The question raised is how this ex-ante trust is defined and used during the supplier selection, when the buyer decides to enter into a relationship with a potential supplier. The phenomenon is studied in the automobile industry, which is experiencing a higher level of dependency on suppliers for sensitive, and at times strategic, components. A single case of a major auto manufacturer is studied using 36 interviews. Our findings show that when selecting the supplier with which to enter a relationship, trust manifests itself on multiple levels: interpersonal, organizational, interorganizational, and network. Contrary to some previous suggestions in the literature, we found interrelationships across these levels.     

Plural governance: The effect of internal production on supplier performance

We suggest that both making and buying the same product or service has several effects on supplier performance. A model is developed and tested by use of answers gathered from the Danish municipalities. The results support the three hypotheses that (1) the negative effects of technological uncertainty on supplier performance decrease when buyers combine internal production and external sourcing, (2) the negative effects of performance uncertainty on supplier performance decrease when buyers combine internal production and external sourcing, and (3) the negative effects of asset specificity on supplier performance decrease when buyers combine internal production and external sourcing. However, the moderating effects depend on how the plurality is measured. The results indicate that internal production may facilitate effective governance of the relationships with external suppliers. Implications for research on make-or-buy decisions and for practice are also discussed.     

Negative default dependence in supplier networks

The financial defaults of suppliers in a supplier network are significant risks and causes of uncertainty for buying firms. Hitherto, it has been largely neglected that default probabilities of suppliers in supplier networks are not independent of each other. We aim to overcome this shortcoming by studying negative supplier default dependencies: situations where a surviving supplier may benefit from the default of another supplier, resulting in a lower default probability. We use empirical data from the automotive supplier industry and copula functions, a method of representing joint distribution functions with particular marginals, to capture the default dependency between automotive suppliers and simulate various scenarios with negative default dependency. We also conduct a comparative static analysis illustrating the significant impact of negative default dependence. Our findings should spur managers to analyze their supplier networks with respect to default dependencies, and to take this phenomenon into consideration when making sourcing decisions.     

Supplier selection-order allocation: A two-stage multiple criteria dynamic programming approach

This paper proposes a two-stage multiple criteria dynamic programming approach for two of the most critical tasks in supply chain management, namely, supplier selection and order allocation. In the first stage, to address multiple decision criteria in supplier ranking, the analytic hierarchy process (AHP) is employed. In the second stage, supplier ranks are fed into an order allocation model that aims at maximizing a utility function for the firm as well as minimizing the total supply chain costs, subject to constraints on demand, capacity, and inventory levels. A dynamic programming approach is crafted to solve the proposed bi-objective model.     

Early supplier integration: the dual role of purchasing in new product development

Interest in early supplier integration in new product development (NPD) has increased as an open innovation approach has become more common in firms. To support supplier integration, the purchasing function of a firm can assume a new ‘dual’ role: contributing to NPD while also managing overall costs. Previous research has offered few insights into how the purchasing function should best be organised so that it will fulfil this dual role. This paper reports on the results of a consortial benchmarking study in which an industry–academic consortium visited and analysed six best‐practice firms. The findings describe how innovative firms organise their purchasing function, distinguishing between ‘advanced sourcing’ and ‘life‐cycle sourcing’ units. The results include the tools that these firms use, such as regular innovation meetings with suppliers and technology roadmaps linking firm strategy, innovation strategy and sourcing strategies. The paper also recommends that researchers shift from a narrow focus on a single project to a broader consideration of supplier and organisational issues in NPD.     

An EOQ lot sizing model with random supplier capacity

This paper presents a general formulation of the inventory lot sizing model with random supplier capacity under the EOQ framework. For a general capacity distribution, we show that the expected cost per unit of time is a unimodal function and pseudo-convex in the ordering quantity. Moreover, we derive some simple data-dependent bounds for both optimal lot size and expected cost per unit of time. In order to illustrate the general model, three types of distributions for the random capacity are analyzed as special cases. These are the uniform, exponential, and truncated normal distributions. For each of these distributions, we find that the maximum cost penalty of using the EOQ lot size instead of the optimal one is almost negligible (not greater than 0.52%, 1.81%, and 0.91% for the uniform, exponential, and truncated normal distributions, respectively). In addition, we extend the general model to allow for the presence of defective units in the quantity received from the supplier. It is shown that this extra randomness does not affect the optimal ordering policy for the original model.     

Improving Supplier New Product Development Performance: The Role of Supplier Development

Suppliers play an increasingly central role in helping firms achieve their new product development (NPD) goals. The literature implicitly assumes that suppliers are able to meet or exceed the quality standards and technological expectations of the firm, and yet, in practice, suppliers often lack the technological capabilities needed to undertake collaborative NPD. In such situations, a firm may choose to intervene and actively develop the supplier's technological and product development capabilities. We develop a theoretical framework that conceptualizes supplier development activities within interorganizational NPD projects as part of a bilateral knowledge‐sharing process: design recommendations, technical specifications, and new technology flow from supplier to the firm, and in turn, the firm can implement supplier development activities to upgrade the supplier's technological capabilities. Antecedents (supplier responsibility, skills similarity, single sourcing strategy) and consequences of supplier development activities (on supplier, product, and project performance) are examined using a sample of 153 interorganizational NPD projects within UK manufacturers. We find broad support for our hypotheses. In particular, we show that the relational rents (in the form of improved product and project performance) attained from supplier development activities in new product development are not achieved directly, but rather indirectly, via improvements in the supplier's creative and technological capabilities. Our results emphasize the importance of adopting a strategic view of the potential returns available from investing in the NPD capabilities of key suppliers, and provide clues about underlying reasons for the suboptimal experiences of many companies' collaborative NPD projects.     

Small and medium-sized firms' import behavior: The case of Danish industrial purchasers

This paper focuses on the foreign purchase behavior of small and medium-sized industrial firms in a small European country, and is guided by three main research issues: (1) to what extent are small and medium-sized firms involved in international sourcing; (2) how do small and medium-sized firms initially make contact with foreign suppliers, and what are their motives for choosing a supplier; and (3) how do small and medium-sized firms perceive relationships with foreign suppliers in terms of perceived problems and cooperation? Through a survey administered in Denmark, the results show that small and medium-sized industrial firms are highly involved in international purchasing both within the European Union and abroad. Surprisingly, this involvement does not appear to be significantly driven by lack of domestic availability. Instead, the primary drivers for choosing a foreign supplier are price and quality. Finally, product adaptation appears to be a significant element of relationship formation between importers and their suppliers. The paper concludes with a discussion of results, implications, and directions for future research.     

Leveraging supplier capabilities: The role of locus of capability deployment

This study adds to the resource‐based view by studying how client firms may gain performance benefits from supplier IT capabilities in market‐based arrangements where the supplier's IT capabilities are readily available to multiple client firms. I argue that the locus of supplier capability deployment, i.e. whether supplier capabilities are deployed at the client (in‐sourcing) or supplier (outsourcing), has implications for client firm performance. The findings show that in‐sourcing leads to complementary effects between supplier IT capabilities and client operational capabilities. In contrast, clients with weaker operational capabilities benefit from outsourcing the respective activity to the supplier, and may even be able to reduce their capability disadvantage through outsourcing. The data on 964 U.S. credit unions contracting with 22 technology solution providers is archival. Copyright © 2012 John Wiley & Sons, Ltd.     

The changing rationale for governance choices: Early vs. late adopters of global services sourcing

Research Summary: This article studies how the logic of firm governance choices varies as a function of the time of adoption of particular sourcing practices. Using data on the diffusion of global business services sourcing as a management practice from early experiments in the 1980s through 2011, we show that the extent to which governance choices are affected by process commoditization, availability of external service capabilities, and past governance choices depends on whether firms are early or late adopters. Findings inform research on governance choice dynamics specifically in highly diverse and evolving firm populations. Managerial Summary: This article considers how firms have chosen delivery models in global services sourcing decisions over time. Based on comprehensive data, we make two major observations. First, we find that firms that began with global services sourcing early, invested mainly in their internal sourcing capacity, while outsourcing only simple tasks to external providers, whereas firms that started later invested more in their capability to outsource various services to increasingly sophisticated suppliers. Second, we find that initial investments in internal or external sourcing capabilities have a strong effect on future choices of delivery models. This explains why, even today, firms vary greatly in how they implement global sourcing decisions, and it suggests that newcomers should learn from their own peer group rather than from highly experienced firms.     

Supplier segmentation using fuzzy logic

Supplier segmentation means that the suppliers of a specific firm are categorized on the basis of their similarities. This supply-side business-to-business (B2B) segmentation is of special importance to companies with many suppliers. Supplier segmentation yields a manageable number of segments, each of which requires a separate strategy. Standard supplier segmentation methods have serious shortcomings, for instance because they fail to make a proper connection between supplier segmentation and other supplier-related activities such as supplier selection and development. Moreover, these standard methods typically use a limited number of segmentation criteria and different sets of criteria are suggested for each method. It is unclear for practitioners how to choose a particular method. The purpose of this paper is to form a practical tool for supplier segmentation taking into account all suggested segmentation criteria. The principal result of this paper is the design of a rule-based method to segment the suppliers of a firm based on two overarching dimensions: supplier capabilities and supplier willingness. The method is applied to a real-world situation to show how the results can be used in practice. A general sensitivity analysis procedure for fuzzy rule-based systems is proposed and then implemented, to identify the most important supplier capabilities and willingness criteria and to formulate better supplier development strategies. A major conclusion of the paper is that the fuzzy logic approach to supplier segmentation is simple to apply in practice, yet considers all available segmentation criteria and their inherent fuzziness in a way that is easily adaptable to a specific industrial context.     

The Chinese paradigm of global supplier relationships: Social control,formal interactions and the mediating role of culture

This paper reports the results of a study that examined how firms can establish successful business relationships with Chinese suppliers. Its aim is to explore salient characteristics of the nature of buyer supplier relationships with the emergence of China as a dominant economic power. Two surveys have been conducted that investigated several factors that inhibit and enable effective supplier relationship management (SRM) between organisations sourcing from China and Chinese suppliers, and explored the impact of cultural characteristics of Chinese management on the nature and performance of supplier relationships. The research highlights the importance of the social control aspect of governance structure of supplier relationships and stresses that both social and formal control mechanisms should be implemented for more effective relationships with Chinese suppliers. It also demonstrates the need for companies to recognise the importance of guanxi and several cultural characteristics of the Chinese style of management in SRM and advocates the need for the development of a hybrid Sino-Japanese and global supplier relationship management paradigm that incorporates elements from the existing SRM models. It generates insights into how the cultural context of emerging markets affects the nature of business relationships and generates a research agenda in the field of supply chain management that can explore the development of new paradigms in supplier relationships management. The main theoretical argument put forward centres on the need for the development of a new global supplier relationship management paradigm that will take into account the cultural elements of the Chinese society.     

Exploiting and creating knowledge through customer–supplier relationships: lessons from a case study

Through an in-depth analysis of a customer–supplier relationship in the information technology market, we illustrate the complexities of vertical coordination processes. We focus on the strategic and organizational criteria that suppliers and customers must design in order to favour interaction between their heterogeneous competencies. In the examined case, the supplier provides general purpose knowledge to be utilized and enriched through the contact with, and fertilization by, application abilities available at the customer level.     

DOES DUAL SOURCING LOWER PROCUREMENT COSTS?*

U.S. defense policy encourages the use of dual sourcing to reduce government procurement costs, but recent theoretical work raises doubts about the benefits of this policy. I study the determinants of dual sourcing and its effects on government procurement costs using a panel dataset of tactical missiles. I find dual sourcing is not driven by failures to reduce costs; instead, it is used more often after incumbent suppliers demonstrate quality control problems, and in settings where tacit collusion is likely to be difficult. After correcting for selection bias, dual sourcing is found to reduce government procurement costs significantly.     

Customer attractiveness,supplier satisfaction and preferred customer status: Introduction,definitions and an overarching framework

Industrial markets are frequently characterized by an oligopolistic market structure. As a result, suppliers may become highly selective with respect to decisions that involve collaborating with certain customers. Buying firms must therefore be more attractive than their rivals to obtain opportunities to collaborate with these selective suppliers. This apparently counterintuitive inversion of the classical marketing approach (that is, relationships that involve buyers competing for suppliers rather than the other way round) constitutes the foundation of the special issue that is introduced in this paper. In this paper, we present key terms and propose a model of preferred customership that uses a social exchange perspective to link customer attractiveness, supplier satisfaction and preferred customer status. The papers that contribute to this special issue are introduced within the context of this framework. Finally, this paper concludes with suggestions for future research directions.     

Concurrent sourcing,governance mechanisms,and performance outcomes in industrial value chains

We examine transaction governance in the context of concurrent sourcing, where a manufacturer relies on sourcing from external suppliers and in‐house production simultaneously. Our focus is on (1) a buyer's use of particular safeguards or governance mechanisms vis‐à‐vis an external supplier and (2) how the effects of these mechanisms on various performance outcomes are influenced by the joint presence of an internal manufacturing branch. We conduct two studies in the apparel industry and show that performance outcomes are a joint function of (1) the individual governance mechanisms that are deployed in a particular relationship and (2) the larger sourcing context (concurrent or singular). Copyright © 2013 John Wiley & Sons, Ltd.