The purpose of this study is to evaluate the drivers of bullwhip effect in supply chain of the pharmaceutical industry. This research is descriptive in terms of method and applied in terms of purpose. Conducting the research, first, based on the reviewing the literature on bullwhip effect in the supply chain, affecting drivers were extracted and were sent to 15 experts in form of a questionnaire. Then, using the fuzzy Delphi method, the final affecting criteria on bullwhip effect in the supply chain of the pharmaceutical industry were identified. Finally, in order to examine the relationships between the 13 basic drivers, another questionnaire was designed and asked the experts to fill it, where based on their answers and using DEMATEL and fuzzy cognitive map methods, critical drivers were determined. FCMapper software was used to conduct fuzzy cognitive map method and MATLAB was used for the DEMATEL method. In terms of centrality index in fuzzy cognitive map method, structured inventory control process, delivery time, inventory storage of chain elements, inventory policy and product return rate are 5 criteria of critical importance. In addition, the indicators of the number of echelons, forecasting (method) error and up-to-date demand forecast are in the eleventh to thirteenth ranks. Based on the results of DEMATEL method, inventory policy, price fluctuations, inventory storage of chain elements, structured inventory control process, differences with the desired inventory and information transparency were identified as the main drivers of bullwhip effect in the supply chain of the pharmaceutical industry. پرونده مقاله

Considering the importance of inventory management in the pharmaceutical industry, especially during the Covid-19 pandemic, this paper investigates a five-echelon pharmaceutical supply chain including component suppliers, manufacturers, retailers, distributors and consumers in order to identify various variables of the inventory management systems and analyze their behavior. Conducting the research, first, based on the reviewing the literature, 29 drivers of bullwhip effect (BWE) in supply chain were extracted. Next, systems dynamics as a powerful approach for modeling complex systems, especially supply chains, is applied to simulate the dynamics of the pharmaceutical supply chain. So, the interactions of the main variables of the system were translated to the dynamic hypotheses and constitute the causal loop diagram. Then, stock and flow diagram was formulated in form of the differential equations. To validate the proposed model, some structural and behavioral validation test were implemented which indicated model’s accuracy. Finally, 4 potential scenarios based on the extent of improvement in information quality, safety stock and lead time were developed and manipulated to analyze their effects on inventory gap, as the main indicator of BWE. The results indicate that the best scenario for the component supplier and manufacturer is 5% increase in the information quality, 10% increase in the safety reserve and 5% decrease in lead time. While for the medicine distributor and medicine retailer; 5% increase in information quality, 5% increase in the safety reserve and 10% reduction in lead time, minimizes stock gap in the shortest time. پرونده مقاله