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.
