JIT purchasing: attribute classification and literature review

To find critical JIT purchasing attributes for manufacturing industry, 56 refereed articles are reviewed. These articles are categorized as conceptual, case and empirical studies. Thirty-four attributes are thus identified. An input-output model is developed to classify these attributes. The inputs to JIT purchasing environment consists of buyer, supplier and joint buyer-supplier actions with 13, six and six attributes, respectively. The interaction between these attributes leads to the JIT purchasing environment. Output of this environment consists of nine attributes. By using the frequency of citation of an attribute as a measure of its importance, consensus is found among conceptual and case studies regarding those attributes of JIT purchasing considered critical. However, many of these attributes have not been investigated empirically, while others have not been rigorously examined. Common supplier evaluation criteria are identified. Benefits and problems with JIT purchasing implementation are discussed. Analysis suggests the need for comprehensive and statistically rigorous empirical studies.     

Toward a Typology of Buyer–Supplier Relationships: A Study of the Computer Industry*

Buyer–supplier relationship typologies are useful analytical tools for purchasing managers in managing exchange relationships with suppliers and monitoring their purchasing portfolios. Existing buyer–supplier relationship typologies are mainly focused on either relational contents or power‐dependence and have limited empirical support for their performance implications. In this study, we developed an alternative buyer–supplier relationship typology that integrates both relational content and power‐dependence dimensions, resulting in four generic relationship types: market, power, autonomous‐link, and constrained‐link relationships. We then performed a longitudinal exploratory investigation of eight leading firms in the U.S. computer industry to explore the performance implications of the typology, using a combinatorial qualitative approach that leverages the strengths of case study research, content analysis, and quasi‐experimental design. The results suggest three theoretical propositions. First, the association between the type of buyer–supplier relationships and buyer firm performance varies such that constrained‐link relationships are superior in terms of operational efficiency while autonomous‐link relationships are superior in terms of product innovation. Second, the positive association between buyer–supplier relational contents (i.e., relationalism) and buyer firm operational efficiency is strengthened as the suppliers' dependence on the buyer firm increases. And finally, the positive association between buyer–supplier relationalism and buyer firm product innovation is weakened as the suppliers' dependence on the buyer firm increases.     

A FRAMEWORK AND MEASUREMENT INSTRUMENT FOR JUST-IN-TIME MANUFACTURING

While Just-in-Time (JIT) manufacturing has emerged as one of the major tools to enhance manufacturing competitiveness, no attempt has been made to develop a reliable and valid measurement instrument for empirical research in JIT. Without such an instrument, generalization beyond the immediate sample is difficult or misleading. We have proposed a JIT framework and developed a valid and reliable instrument with 16 summated scales for dimensions that capture essential aspects of JIT useful in assessing its impact in manufacturing environments. In addition, we discuss in detail the interactive nature of JIT practice. And, we propose a step-by-step approach to reliability and validity testing. Four JIT practices (equipment layout, pull system support, supplier quality level, and Kanban) are identified as major contributing factors to JIT performance.     

An integrated vendor-buyer cooperative inventory model for items with imperfect quality

This article develops a model to determine an optimal integrated vendor-buyer inventory policy for flawed items in a just-in-time (JIT) manufacturing environment. The aim is to minimize the total joint annual costs incurred by the vendor and the buyer. The proposed model extends the integrated vendor-buyer inventory model by accounting for imperfect quality items. The expected annual integrated total cost function is derived and an analytic solution procedure is proposed to determine the optimal policy. Finally, numerical examples are also given to illustrate the solution procedure presented in this article.     

Coopetitive Buyer–Supplier Relationship: An Investigation of Bargaining Power,Relational Context,and Investment Strategies

This study proposes an analytical approach combined with a behavioral experiment for a joint examination of the competitive and cooperative (i.e., coopetitive) relationship between a buyer and a supplier. Specifically, the article considers the scenario in which the buyer and the supplier invest in strategic capabilities to increase their relative bargaining power. The article examines how dynamic investments in strategic assets are influenced by the locus of bargaining power and by the underlying context (synergistic vs. adversarial) of the interfirm relationship. The dynamic evolution of bargaining power is also examined. A dynamic game model is considered to examine the evolution of investment strategies in critical resources and to investigate the issues of bargaining power in a buyer–supplier dyad. Equilibrium expressions for the investment strategies of the buyer and the supplier are presented and their implications for buyer–supplier relationships are examined. The behavioral experiment complements the analytical model and examines the correspondence between optimal behavior suggested by the analytical model and the boundedly rational behavior of decision makers in an experimental context. The results from the model and behavioral experiments suggest that the strategies are a function of the risk‐adjusted returns obtained from investments. The experiment shows that, in a synergistic relational context when the buyer maintains bargaining power, the investment shifts of the buyer and the supplier accord well with theoretical predictions. In an adversarial relational context, the results of the experimental study do not correspond well with that predicted by the theoretical model. The implications of the results are discussed and directions for future research are presented.     

Managing Risk of Supply Disruptions: Incentives for Capacity Restoration

A supplier facing the prospect of disruption has to decide whether or not to invest in restoration capability. With restoration capability, if disruption occurs, additional costly effort can be exerted to rebuild capacity, although its outcome is uncertain. We study how a firm (buyer) can use incentive mechanisms to motivate a supplier's investment in capacity restoration, and compare this approach with the traditional approach of diversifying part of the order to an expensive but reliable supplier. Under a Restoration Enhancement (RE) strategy, the buyer uses price and/or order quantity incentives to encourage the supplier's restoration investment decision. Two different cases are considered—when the incentive is committed to ex ante (prior to disruption) and when it is committed to ex post (after disruption). In contrast, under a Supplier Diversification (SD) strategy, the buyer splits orders between a reliable supplier and an unreliable supplier to hedge against the disruption risk. Here, the buyer does not provide any separate incentive to the unreliable supplier. Our analysis indicates that under the RE strategy, where the buyer offers incentives, both the buyer and the supplier (weakly) prefer the ex ante commitment over the ex post one. Furthermore, the RE strategy is preferred over the SD strategy when the unreliable supplier's restoration outcome is more predictable or when a high restoration outcome is more likely. However, the buyer's preference for the SD strategy increases as market demand increases.     

Governance Choice,Sourcing Relationship Characteristics,and Relationship Performance

Past work on exchange relationships has debated the efficacy of partnership versus arm's‐length governance on performance of a buyer–supplier relationship. However, how these governance approaches leverage key supplier specific relationship characteristics has not been examined. In this study, we examine the moderating role of governance choice (arm's‐length versus partnership governance) in leveraging key supplier specific characteristics to achieve superior performance for the buyer in a relationship. Specifically, drawing from residual rights theory, we argue that the governance choice buyers make moderates the impact of supplier flexibility, supplier human capital and relationship dependency on performance. Our findings suggest that, for a buyer, the benefits of supplier flexibility and relationship dependency are better realized in partnership governance as opposed to arm's‐length governance. Further, our findings suggest that although buyers choose a specific governance approach consistent with their outsourcing motivation, the choice of governance is critical to leveraging the impact of supplier characteristics due to the moderation effects studied. We elaborate on these effects and discuss the implications of our findings.     

Supplier Opportunism in Buyer–Supplier New Product Development: A China‐U.S. Study of Antecedents,Consequences, and Cultural/Institutional Contexts

Collaborating with a supplier in a buying firm's new product development (NPD) project is commonly advocated and adopted, but does not always improve project performance. Some pre‐existing collaboration contexts, such as buyer–supplier NPD projects, are especially exposed to supplier opportunism due to the uncertain nature of the collaboration process. Adopting agency theory and transaction cost theory perspectives, we examine: (i) contextual antecedents and project consequences of supplier opportunism and (ii) if these causal influences vary in different cultural and institutional contexts. Using a survey sample of 214 United States (U.S.) and 212 Chinese buying firms’ responses about buyer–supplier NPD projects, we find that supplier opportunism is significantly influenced by the task and relational contexts. We also show that supplier opportunism damages both design quality and efficiency, two aspects of project performance. When comparing U.S. to China, we find that task and relational contexts have a greater impact on supplier opportunism in the U.S., but design efficiency is less hurt by supplier opportunism there. Finally, we show challenges of preventing supplier opportunism in certain NPD collaboration contexts, and offer solutions for overcoming these challenges.     

Mechanisms to Induce Buyer Forecasting: Do Suppliers Always Benefit from Better Forecasting?

In this study, we consider a supplier's contract offerings to a buyer who may obtain improved forecasts for her demand over time. We investigate how the supplier can take advantage of the buyer's better forecasts and what kind of contracts he should offer to the buyer in order to maximize his profits. We model a natural forecast evolution where the buyer can obtain a more accurate forecast closer to the selling season. We assume there is information asymmetry between the buyer and the supplier at all times in that the buyer understands her demand better than the supplier. Three types of contracts that the supplier can offer are considered: (1) one where a contract is offered before the buyer has a chance to obtain improved forecasts, (2) one where a contract is offered after the buyer has obtained improved forecasts, and (3) a contingent (dynamic) contract which offers an initial contract to the buyer before she obtains improved forecasts, followed by a later contract (contingent on the initial contract) offered after improved forecasts have been obtained. We consider two scenarios: (1) where the supplier is certain that the buyer can obtain more accurate forecasts over time, and (2) where the supplier is uncertain about the buyer's forecasting capability (or forecasting cost). In the first scenario, we show that among the three types of contracts, the contingent contract is always the most profitable for the supplier. Furthermore, using the contingent contract, the supplier always benefits from higher accuracy of the buyer's demand forecasts. In the second scenario, we explicitly model the supplier's level of certainty about the buyer's capability of obtaining better forecasts, and explore how the supplier can design contracts to induce the buyer to obtain better forecasts when she is capable.     

基于提前订购策略的供需双方动态博弈模型研究

在两级供应链环境下,相对于传统的即时订购策略,通过以较低批发价提供一个提前订购的机会,给予购买商两次订货机会,那么供应商和购买商的利润可以实现帕累托改进.同时如果供应商在提供提前订购机会的同时收取一个固定费用,则可以进一步优化模型.建立了一个具体的模型,用逆向归纳法计算出了均衡解,并对不同策略下的均衡结果进行了对比分析.     

Just-in-time purchasing: an empirical investigation

The just-in-time (JIT) literature suggests that, for JIT to be successful, a manufacturing firm has to make changes in its purchasing operations. However, empirical examination of the JIT purchasing related issues is limited. For example, a literature search identified 49 JIT purchasing articles. Of these, only 14 are empirical studies; two dealing with statistical testing of a few JIT purchasing issues. This comprehensive empirical study is undertaken to investigate (a) changes in the purchasing attributes since JIT implementation, (b) supplier evaluation cri-teria, and (c) problems with JIT purchasing implementation. Statistically significant changes are observed in 28 out of 32 attributes identified in the literature, suggesting that the manufacturing firms are successfully implementing JIT purchasing programmes. Of the 14 supplier evaluation criteria, the empirical investigation shows nine of them being important. Erratic demand for the product and customized product are found to be problematic (but not very problematic as suggested in the JIT literature( in JIT purchasing implementation.     

Procurement strategies in the presence of the spot market—an analytical framework

This paper investigates a problem in which a buyer can procure from a regular supplier as well as from a supplier in a spot market, possibly formed over the Internet. The contract with the regular supplier specifies a predetermined order volume and price, while the spot market has unlimited supply but a varying spot price. We analyse this problem from a buyer/supplier perspective, and an analytical model is developed to analyse two distinctive procurement strategies: the pure procurement system (PS) and the mixed procurement system of regular supplier with a supplier in spot markets (MS). Without loss of generality, we obtained a closed-forms solution that enabled us to provide numerical analysis on the procurement strategies, and allowed us to compare further the different characteristics between PS and MS. The results of our analysis demonstrate that the use of spot market could effectively mitigate the risk associated with demand uncertainty facing the buyer. The results also show that adopting MS can generate a higher buyer's profit than the PS, and significant supply-chain profit improvements can indeed be achieved through buyer/supplier coordination. Furthermore, spot price volatility leads to the facilitation of the use of spot markets, improving the buyer and the supply-chain profitability.     

Configuration of flexibility strategies under supply uncertainty

In this paper, we study a buyer׳s configuration of flexibility strategies under supply uncertainty. His main supplier׳s production process is uncertain, and he can either choose pricing flexibility (setting prices depending on the available supply) or operational flexibility (requesting a contingent order from a backup supplier). As the buyer may or may not find a suitable contingent supplier ex post, we study two scenarios that the backup supplier׳s supply is infinite, and that this supply is random. We also include the factor that the main supplier may determine the wholesale price. We demonstrate that the adoption of flexibility strategies is controlled by threshold policies in different scenarios whether the main supplier determines the wholesale price or not. We also investigate how the buyer׳s attribute (finding a suitable contingent supplier) affects the configuration of flexibility strategies.     

The impact of inter-organizational information systems-enabled external integration on capabilities of buyer–supplier dyads

Increasingly, firms are adopting two major supply chain management initiatives: to undertake external integration with supply chain partners and to implement inter-organizational information systems (IOSs). However, academic researchers have not adequately investigated effects of these types of initiatives. Using empirical data from 154 buyer–supplier dyads, we examined the direct and indirect effects (through external integration) of IOS usage on capabilities of buyer– supplier dyads. We found that external integration plays a mediating role in the relationship between IOS usage and capabilities of buyer– supplier dyad. This is the first study to investigate the effects of IOS usage and external integration on capabilities of buyer–supplier dyad.     

Dynamic Procurement,Quantity Discounts,and Supply Chain Efficiency

We study a model with a single supplier and a single buyer who interact multiple times before the buyer sells her product in the end‐consumer market. We show that when the supplier uses a wholesale price contract, even under perfect foresight, the supplier, the buyer, and the end consumers benefit from multiple trading opportunities versus a one‐shot procurement agreement.     

在弹性需求和物品易变质条件下数量折扣定价模型

研究在弹性需求和易变质物品条件下,当供应商和零售商独自决策时,供应商如何确定最优数量折扣问题。基于Stackelberg博奕建立了数学模型,证明了零售商的出售价格随供应商出售价格的降低而降低,从而需求量增大。当供应商给予价格折扣时,零售商的利润是增加的。在此基础上,给出了最优数量折扣的计算方法。对供应商和零售商单独决策时,供应商利用数量折扣对供应链进行协调产生的系统利润与供应商和零售商联合决策时的系统利润做了数值分析和比较。结果表明,供应商采用数量折扣的方法使供应链协调是有效的;价格折扣随价格敏感系数的增大而增大,随变质率的增大而减小。     

一种基于期权的供应商能力预订模型

在供应链中,合作企业实现风险共担,利益共享是供应链管理的基本目标。本文通过引入期权机制,提出了制造商预订上游供应商的生产能力的数学模型,使之能以较低的风险获取外部资源,以保证经营目标的实现。同时,也能使供应商通过期权降低自身的经营风险,增强收益的能力,最终实现供应链利益的整体协调。