مروری بر محرک ‌های (پیشران های) پیچیدگی زنجیره تامین A review of supply chain complexity drivers

۱٫ Introduction Supply chain is a complex network of business entities involved in the upstream and downstream flows of products and/or services, along with the related finances and information (Beamon, 1998; Lambert, Cooper, & Pagh, 1998; Mentzer et al., 2001). Supply chain management (SCM) involves the systemic and strategic coordination of these flows within and across companies in the supply chain with the aim of reducing costs, improving customer satisfaction and gaining competitive advantage for both independent companies and the supply chain as a whole (Cooper & Ellram, 1993; Cooper, Lambert, & Pagh, 1997; Mentzer et al., 2001). Operating in a dynamic and uncertain environment, a supply chain is defi- nitely a complex system with various companies, high number and variety of relations, processes and interactions between and within the companies, dynamic processes and interactions in which many levels of the system are involved and vast amount of information needed to control this system. Complexity inherent in the supply chain is observed in different forms and origins: static complexity, that is related to the connectivity and structure of the subsystems involved in the supply chain (e.g. companies, business functions and processes); dynamic complexity, that results from the operational behavior of the system and its environment; and decision making complexity that involves both static and dynamic aspects of complexity. The complex nature of supply chain adds to difficulty of managing the supply chain, so that it almost becomes common sense to say SCM is about managing the complexity of the supply chain. Although there are certain difficulties in dealing with complexity in the supply chain, numerous studies support that managing complexity leads to achieving better supply chain performances (A.T. Kearney, 2004; Blecker, Kersten, & Meyer, 2005; Bozarth, Warsing, Flynn, & Flynn, 2009; Koudal & Engel, 2007; KPMG., 2011; Perona & Miragliotta, 2004; PricewaterhouseCoopers, 2006; Vachon & Klassen, 2002; van der Vorst & Beulens, 2002). Thus, integrating complexity management into SCM is a necessary action. Before reviewing the approaches to manage complexity in the supply chain, it is crucial to characterize the supply chain complexity and discuss its drivers. Understanding and analyzing the complexity drivers in advance may allow developing a clear strategy in efforts to manage the supply chain complexity. The aim of this paper is to review the typical complexity drivers that are faced in different types of supply chains and present the complexity driver and solution strategy pairings based on good industry practices. A meta-synthesis of good practices serves as a guideline in developing supply chain complexity management system. The remainder of the paper is organized as follows. Section 2 gives a review of the literature on supply chain complexity and its drivers. Section 3 presents solution strategies to deal with complexity extracted from various good practices using a systematic review. Section 4 discusses complexity management approaches that would assist decision-makers in formulating appropriate strategies to deal with complexity in their supply chains. Section 5 concludes the paper and points out directions for future research. ۲٫ Drivers of supply chain complexity Complexity in a supply chain grows, as customer requirements, competitive environment and industry standards change, and as the companies in the supply chain form strategic alliances, engage in mergers and acquisitions, outsource functions to third parties, adopt new technologies, launch new products/services, and extend their operations to new geographies, time zones and markets (A.T. Kearney, 2004; BCG., 2006; DeloitteToucheTohmatsu., 2003; KPMG, 2011; PricewaterhouseCoopers, 2006). In other words, the growth of supply chain complexity accelerates with trends such as globalization, sustainability, customization, outsourcing, innovation, and flexibility. We can distinguish between three types of supply chain complexity: static, dynamic and decision making. While static (structural) complexity describes the structure of the supply chain, the variety of its components and strengths of interactions; dynamic (operational) complexity represents the uncertainty in the supply chain and involves the aspects of time and randomness. The static–dynamic distinction has been primarily used to study complexity in manufacturing systems (Calinescu, Efstathiou, Schirn, & Bermejo, 1998; Calinescu, Efstathiou, Sivadasan, & Huaccho Huatuco, 2001; Calinescu, Efstathiou, Sivadasan, Schirn, & Huaccho Huatuco, 2000; Deshmukh, Talavage, & Barash, 1992; Deshmukh, Talavage, & Barash, 1998; Frizelle & Woodcock, 1995; Huaccho Huatuco, Efstathiou, Calinescu, Sivadasan, & Kariuki, 2009) and supply chains (Isik, 2010; Sivadasan, Efstathiou, Frizelle, Shirazi, & Calinescu, 2002; Sivadasan et al., 1999). Decision making complexity involves both static and dynamic aspects of complexity (Calinescu, Efstathiou, Huaccho Huatuco, & Sivadasan, 2001; Calinescu, Efstathiou, Sivadasan, et al., 2001; Efstathiou, Calinescu, & Blackburn, 2002; Manuj & Sahin, 2011). From the static aspect, the supply chain system is made up of high number of elements, variety and interactions, and considering them all when making a decision goes beyond the capacity of the human decision maker (Miller, 1956; Simon, 1974; Warfield, 1988). From the dynamic aspect, the fact that the system is dynamic, non-predictable, and non-linear adds another layer of complexity to decision making in the supply chain. As a result, complexity of decision making in the supply chain is associated with the volume and nature of the information that should be considered when making a supply chain related decision (Efstathiou et al., 2002; Serdarasan, 2009). One should note that the three complexity types are interrelated, and they should not be considered in isolation. A supply chain complexity driver is any property of a supply chain that increases its complexity. The classification of types of supply chain complexity (i.e., static, dynamic, decision making) corresponds with the classification of complexity drivers according to the way they are generated: via physical situation (e.g., number of products), operational characteristics (e.g., process uncertainties), dynamic behavior (e.g., demand amplification), and organizational characteristics (e.g., decision making process, IT systems) (Childerhouse & Towill, 2004; Towill, 1999). Another classification of drivers is according to their origin: internal, supply/demand interface, and external/environmental drivers (Blecker et al., 2005; Childerhouse & Towill, 2004; Isik, 2011; Mason-Jones & Towill, 1998; Wildemann, 2000). Internal drivers are generated by decisions and factors within the organization such as the product and processes design. These drivers are relatively easier to leverage since they remain within the span of control. Drivers generated within supply and/or demand interface (in cooperation with suppliers/customers) are related to the material and information flows between suppliers, customers and/or service providers. These drivers are somewhat manageable since they remain within the span of influence and the level of coordination between supply chain partners plays a significant role when dealing with these drivers. Thus, power and trust mechanisms that affect the nature of supplier/customer relations are also important factors which need to be considered as complexity drivers. External drivers are generated through mechanisms that the company has little, if any, control over such as market trends, regulations and other various environmental factors. Table 1 gives an overview of classification of supply chain complexity drivers according to type and origin and Table 2 summarizes the related literature. As seen in Table 2 the related literature mainly focuses on internal and interface complexities and the number of studies dealing with the external complexity drivers appears to be smaller in number. This is mainly due to the fact that the external drivers are outside the system boundary of the supply chain, i.e. out of the span of control of the decision maker, yet they can be monitored, analyzed, and acted upon with robust decisions to adapt and change. Größler, Grübner, and Milling (2006)’s framework that discusses this issue from the manufacturing company’s perspective could be extended throughout the supply chain. Examining how the supply chain system interacts with its environment in this way allows us to gain a greater understanding of its behavior. When we look at the number of papers categorized according to type of complexity, it appears that decision making complexity has attracted much less scholarly attention than the static and dynamic types. It should be noted that a majority of the reviewed papers involve issues related to complexity of the supply chain decision making, since decision making complexity is a combination of dynamic and static complexities perceived by the decision maker during the decision making process. However their particular focus is not primarily on decision making complexity, which is the reason why decision making complexity seems to receive relatively little interest.