توسعه معیارهای انتخاب تامین کننده پایدار برای تهویه مطبوع خورشیدی: رویکرد یکپارچه  Developing sustainable supplier selection criteria for solar air-conditioner manufacturer: An integrated approach

. Introduction Nowadays, supply chains are increasingly exposed to increased competition, exacerbating scarcity of resources, stricter regulations, and requirements of stakeholders [10,22]. There is also a growing awareness of the requirement for companies to pro-actively build sustainability principles into their supply chain management [34]. Sustainable supply chain management (SSCM) has been considered as an integration and realization of a company’s economic, environmental, and social objectives in coordination of critical business processes to improve the company’s long-term economic performance [10]. Supplier is one of the most critical factors for the success of sustainable supply chains (SSC). This is because collaboration with economically, environmentally, and socially strong suppliers could improve the supply chain performance [8]. Thus, to maintain a strategically competitive position, it is necessary for operations, purchasing and supply chain managers to select the most suitable supplier [5,6]. Accurate supplier selection helps organizations find the suitable supply chain partners and eventually enhance the organizational performance [11]. Although many studies exist on the topic of supplier selection, the research on the selection of sustainable supplier is fairly rare [19,20,24]. Most of them focus on environmental supplier selection, and they do not consider social aspects. Moreover, it is inappropriate to assume all the supplier selection criteria as independent due to the complexity and uncertainty of the operation environment. There are complex relationships among the supplier selection criteria, e.g. Ecodesign may have influences on Reduce, Reuse and Recycle of the product, and the Delivery may influence the Resource Consumption. It is necessary for managers to figure out such criteria interrelationships in practice, because the causal-effect relations between selection criteria provide valuable information for companies to discern the potential areas for further sustainability improvement. However, the previous supplier selection approaches scarcely consider the relationships among criteria which may cause underestimation or overestimation of the weights of sustainable supplier selection. Furthermore, the previous approaches often require much additional data. Although some researches try to use decision making trial and evaluation laboratory (DEMATEL) to handle this problem (e.g., [17,11], they often assume that the evaluation criteria are equally important in dealing with the interrelationships of criteria, which does not actually happen in the real supplier selection decision making. In fact, the internal strength of one evaluation criteria may have impact on its influence (intensity of affecting), and eventually affect the supplier selection performance. To fully and accurately reflect the positions of selection criteria, it is also necessary to calculate criteria weights considering their interrelationships. In this way, it helps to avoid potential risk of selecting the wrong suppliers. Besides, it is hard to acquire accurate decision makers’ preferences in the supplier selection process, because the decision information in form of linguistic terms is often subjective and vague. Based on the above discussions, the objective of this research is to develop an integrated approach to determine the final criteria weights of sustainable supplier selection considering the interrelationships among evaluation criteria with different prior importance. The proposed methodology integrates the merit of pairwise comparison method in determining relative importance of sustainability criteria, the strength of the DEMATEL in manipulating the complex and intertwined criteria with fewer data, and the rough number’s advantage in flexibly dealing with vague information. The proposed approach helps to elucidate the causal relationships between sustainability criteria by using the framework of DEMATEL. It provides a mechanism of integrating both strength (importance) and influence of the criteria to fully reflect the position of sustainability criteria, which helps to avoid potential risk of selecting the wrong suppliers. The necessary information derived from the proposed method, such as interactions between criteria and the inner importance of criteria, can help companies to identify the potential areas where sustainable suppliers need to improve. With the proposed method, companies can help their suppliers improve sustainability for better management of sustainable supply chain operations. Moreover, the rough number used in the proposed method can flexibly manipulate such vagueness. To the best of our knowledge, no previous studies have investigated the subject of sustainable supplier selection with this kind of integrated method. This research results will improve the managers’ view on the nature of interrelationships between the sustainable supplier selection criteria. Besides, the proposed method can be widely used as a structural model for analyzing intertwined factors and causal relationships between them. In particular, the proposed method can be applied to assess alternatives when both strength (importance) and influence of criteria cannot be neglected.