تعدیل اثر تامین منابع جهانی بر موجودی انبارها از طریق مدیریت زنجیره تامین

In recent years, companies have paid growing attention to supply chain management at a global level. With regard to the upstream part of the supply chain, the need for better suppliers, the research into specific competences and concerns related to international competition have forced companies to improve their ability to cope with suppliers located in different countries around the world. The literature suggests that the geographical distance of suppliers should create higher inventory levels primarily because of longer and more uncertain lead times. However, as this paper aims to demonstrate, companies can limit this effect by means of specific investments in the supply chain and in their relationships with suppliers. The empirical analysis is based on data from the last edition of the International Manufacturing Strategy Survey (IMSS). The results show that companies performing global sourcing have invested in supply chain management (SCM) and that this has been helpful in keeping their inventories under control.

During the last 20 years, companies have witnessed a considerable expansion of their supply chains into international locations (Taylor, 1997 and Dornier et al., 1998). Companies’ supply chains have tended to expand beyond national barriers because of increasing competitive pressures, reduced trade barriers and advancements in transportation and communication technologies (Schary and Skjøtt-Larsen, 2001 and Hülsmann et al., 2008). This phenomenon, which is still in progress, has introduced increased complexity into the supply chain (e.g., new and more suppliers, variable exchange rates, changing local policies) that can reduce firms’ performance if they are not properly managed (Hülsmann and Grapp, 2005). As a result, academic interest has been devoted to the concept of global supply chain management (Prasad and Babbar, 2000). Global supply chains have been analyzed from different perspectives: products’ global value chains (Gereffi et al., 2005), networks (Chung et al., 2004), double or multi-echelon systems (Arda and Hennet, 2006) or (focusing on a company perspective) the coordination and management of sourcing, manufacturing and distribution activities on a global scale (Murray et al., 1995b, MacCarthy and Atthirawong, 2003, Bello et al., 2004 and Cohen and Mallik, 1997). Global sourcing – here defined as the purchasing of goods outside the geographical area to which the company belongs – has been specifically considered and analyzed from this last managerial perspective (e.g., Kotabe and Omura, 1989, Murray et al., 1995a and Murray et al., 1995b). Recent studies ( Trent and Monczka, 2003 and Cagliano et al., 2008) show that global sourcing, even if still relatively diffuse, is significantly growing in popularity. Cagliano et al. (2008), for example, provide evidence of global sourcing practice based on more than 600 companies in the assembly industry from 20 different countries. The authors report that the majority of the companies considered in their study (about 64% of the sample) do only 4% of their spending outside their continent. This limited rate of adoption may be due to several inhibiting factors, such as management experience or logistical costs. However, a significant number of companies are still looking for suppliers abroad: e.g., Cagliano et al. (2008) find that the overall sample used in their work displayed an average growth in purchases outside the continent of about 4% between 2001 and 2004. This growth trend has driven researchers to more thoroughly analyze the impacts of global sourcing on companies’ processes and performance to determine the best ways to cope with it. In fact, recent studies have shown that global sourcing, especially from low-cost sources, makes it harder to manage the cost versus response trade-off (Nair and Closs, 2006 and Lowson, 2003). One evident effect is that longer lead times and less dependable deliveries from suppliers require companies – ceteris paribus – to maintain higher safety stocks to preserve the same service level. This has been confirmed at an aggregate level; in 2005, increased import ratios for US manufacturing companies were reflected in additional costs of raw materials inventories (Han et al., 2008). However, limited empirical research has been done on this topic. In particular, in this work, attention will be devoted to two related questions. First, this paper aims to explore the relationship between global sourcing and inventory levels. Secondly, we aim to understand how companies can overcome the problems mentioned above when they increase the use of foreign suppliers by means of upstream supply chain management (SCM). Specifically, this paper aims to contribute to our understanding of this issue by providing evidence of the relationship between global sourcing, upstream SCM and inventory performance. The remainder of the paper is therefore structured as follows. In the next section, the concept of global sourcing and its motivators and inhibitors are described according to the literature. Next, the literature on the relationship between global sourcing and inventory levels is reported, highlighting the role of upstream SCM in moderating this relationship. Then, the research objectives and methodology are detailed, and the empirical analysis is described. Subsequently, a proper discussion of the empirical results is provided, and, finally, we draw conclusions and suggest potential future research.

This work studies the impact of global sourcing on inventory levels. The results of the paper provide evidence of a relevant negative impact of this practice on inventory performance that can be partially reduced via the adoption of proper supply chain practices. The main contribution of this paper is the evidence that it provides of the existence of a complex relationship between the decisions that companies make regarding sourcing and their performance. Moreover, these results help to explain why previous papers have not been able to identify the very strong impact of global sourcing on inventory levels. From a managerial point of view, this work highlights that managers should pay attention when they decide to extend their purchasing internationally; proper investments should be planned to align the supply chain and help the firm to cope with the counter-effects of global sourcing. From a general perspective, the decision to source globally is critical and should not be made without a clear understanding of its implications and without the consideration of whether specific investments should be performed at the same time. While this paper provides an original contribution, we would also like to highlight its major limitations and relevant possibilities for future research. First of all, we have measured global sourcing only in terms of the percentage of purchasing done on a different continent than that where the company is located. However, differences may also arise according to where specifically purchasing is conducted because there may be different logistical infrastructures, country-specific risks, etc., at play. These factors may also depend on the country where the company is based as different logistical limitations may exist. Secondly, we have limited our analysis to the impact of global sourcing on materials inventory levels. Future studies should take into account other aspects of performance (e.g., service level to production, quality of materials, etc.) to completely assess the counter-effects of global sourcing. In particular, we may expect that global sourcing will sometimes lead to lower operational performance in areas other than inventory levels (e.g., on-time delivery, lead time, etc.) and that there are other managerial motivators, such as cost, innovativeness, and technology, that encourage the globalization of purchasing. The literature, however, lacks significant contributions that empirically show whether these relationships really exist. Moreover, future contributions should devote attention to the downstream portion of the supply chain. Specifically, it would be interesting to replicate this study considering the impact of the globalization of downstream processes (i.e., global distribution) on inventory performance. The replication of this study considering the downstream supply chain could be helpful in allowing companies to identify how global distribution should be managed and thus how the global supply chain plays a role in determining company performance. The paper also highlights differences in the performance of companies adopting different sourcing strategies. In particular, global sourcing companies that have invested in SCM have inventory performance comparable to that of local sourcing companies. However, global sourcing companies that have not invested in SCM have the worst inventory performance of the entire sample. Of course, this can be done deliberately if inventories are not too expensive; thus, the cost of stocks might be a variable to include in future studies. Finally, this paper shows which SCM practices are more applicable in a global sourcing context and indicates their expected impact on inventory levels. One might be able to further develop these results by considering a broader or more detailed set of practices, but this study nevertheless provides a preliminary idea of the SCM investment pattern followed by some companies. In fact, internal investments in the purchasing function (e.g., supply strategy) are easier to undertake and more beneficial for inventories in the context of global sourcing, but external investments (e.g., integration and coordination with suppliers) can facilitate further improvements.