چشم انداز سازمانی در کنترل موجودی: تئوری و یک مطالعه موردی

Inventory control is a well-covered area in literature. Nowadays, many concepts and techniques are available for effectively controlling inventories. Eminent examples are stochastic models to determine order quantities, techniques for forecasting demand and different kinds of ABC analysis. Remarkably enough, the theoretical backgrounds of these concepts and techniques show a great deal of similarity: they all stem from the field of operations management and operations research. Despite the value of the available concepts, such a one-sided approach has its limitations in practice. In this article it is argued that it is important to take a broader view when dealing with practical inventory control problems. First of all, an organizational perspective on inventory control is developed. The main idea behind this perspective is the importance of the organizational context of inventories. This means that in addition to the traditional points for attention, such as order quantities and replenishment strategies, other aspects need attention as well. They are, for example, the allocation of responsibilities and authorities regarding inventory management, the quality of inventory information and the relevant decision-making processes. These contextual factors as well as the traditional factors are mapped out and integrated into a framework to be used in solving practical inventory control problems. One of the main features of the framework is that it is useful in both analyzing and redesigning an inventory situation. Secondly, this article describes the results of a case study regarding the application of the organizational perspective to a practical inventory control problem. The central issue of the case study is the spare parts inventory of a missionary aviation organization in Africa. The case study shows that the organizational perspective on inventory control is very helpful in dealing with inventory control problems. It is illustrated that taking into account the organizational context of inventories, especially the responsibilities and authorities of the persons concerned, is a necessity to accurately understand inventory control problems. In addition, it is illustrated that the organizational perspective leads to a more appropriate redesign.

During the last few decades inventory control has been the topic of many publications. It may fairly be called one of the classics in operations literature. As a result, a large collection of concepts and techniques is available for effectively controlling inventories. There are for example stochastic models to determine order quantities, techniques for forecasting demand and different kinds of ABC analysis. Recently management systems such as manufacturing resource planning (MRP) and enterprise resource planning (ERP) have been added. However, most of these contributions have similar theoretical background: the field of operations management and operations research. This means the concepts and techniques are mainly based on mathematical assumptions and modeling inventory situations. Although this established approach to inventory control has proved to be very valuable in determining inventory parameters and planning resources, its value can be questioned in dealing with practical inventory control problems. Plossl and Welch for instance state that many firms have inventory control techniques working but they are not reducing inventories. On the other hand, some others are doing a fine job of managing the total inventory investment even without these tools (Plossl and Welch, 1979, p. 26). In addition, nowadays’ authors realize that many of the quantitative methods from the field of operations management and operations research are insufficient to cope with today's organizational complexity (e.g. Hayes, 1998; Lovejoy, 1998; Machuca, 1998). These authors favor a broader scope on operations management issues, including qualitative aspects and linkages with other functional areas in an organization. Therefore, there seems to be a need for an extended view on inventory control. In this article we argue that it is highly important to take the organizational context of inventories into account when dealing with inventory control problems. This means that in addition to the traditional points for attention, such as order quantities and replenishment strategies, contextual aspects need attention as well. They are for example the allocation of responsibilities and authorities regarding inventory management, the quality of inventory information and the relevant decision-making processes. These contextual factors as well as the traditional factors can be integrated into an organizational perspective on inventory control. The development and practical application of this organizational perspective are the main topics of this article. The article is organized as follows. First, the organizational perspective on inventory control is developed. To that end, the organizational context of inventories is investigated to determine aspects that play a part in inventory control. Second, a framework is presented to facilitate the application of the organizational perspective to practical inventory control problems. The third section of this article describes the research methodology of a performed case study in which the organizational perspective has been applied. The case study regards the spare parts inventory of a missionary aviation organization in Africa. Fourth, the results following from the case study are presented. It can be concluded that taking the organizational context of inventories into account leads to a better understanding of the problem and to a more appropriate redesign of the inventory situation. The final section of this article summarizes the conclusions.

From the above several conclusions can be drawn. First, this article has lead to a broader view on inventory control. This broader view regards the organizational perspective on inventory control that has been developed. The main idea behind this perspective is the importance of the organizational context of inventories for the effectiveness of inventory control. It has been argued that the traditional approach to inventory control from the fields of operations management and operations research pays little or no attention to the organizational setting of inventories. However, the organizational context of inventories contains several factors that play a part in inventory control. They have been identified as the allocation of inventory tasks, decision-making processes regarding inventory, communication processes concerning inventory information and behavior of the parties involved in inventory management. In the organizational perspective on inventory control these four dimensions are taken into account along with traditional aspects of inventory control. It can be concluded that this organizational perspective on inventory control can be of large value in practice. The case study regarding the spare parts inventories of MAF Europe has shown that factors from the organizational context of an inventory can indeed play a significant part in inventory control problems. In particular, the case study has emphasized the importance of coherence between the dimensions. Second, in this article a way of approaching practical inventory control problems from the organizational perspective on inventory control has been developed. This approach consists of a set of guidelines referring to a problem-solving process. In the first place it has been argued that a diagnosis of an inventory system should contain a comprehensive description. This means both traditional characteristics of an inventory system and the four dimensions in the organizational context of an inventory should be described. Secondly, it has been argued that an inventory system should be analyzed by paying attention to each of the dimensions separately and subsequently to the coherence between the dimensions. Thirdly, when redesigning an inventory system each of the traditional and contextual dimensions should be taken into consideration, although it might not be needed to change them all. This is due to the interaction between the dimensions. It can be concluded that this proposed set of guidelines is a helpful tool in solving practical inventory control problems. It aids in systematically applying the organizational perspective on inventory control. The case of MAF Europe has shown that this way of applying the organizational perspective leads to a more accurate understanding of an inventory control problem and a more appropriate redesign of an inventory system. Nevertheless, future research is required for the organizational perspective on inventory control to grow in size. This article has initiated its development, but it mainly focused on the creation of an instrument that would be most useful in practice. Therefore, further research needs to be conducted to consolidate the foundations of the perspective. In this respect the relation between the organizational context of inventories and the effectiveness of inventory control needs to be investigated in more detail. In particular, it is worthwhile to explore the specific contributions of the dimensions that have been identified in this article research is likely to contribute to a refinement of the guidelines proposed in this article, so that the practical employment of the organizational perspective on inventory control will be further improved as well.