RAIRO-Oper. Res. 55 (2021) 2525–2543 RAIRO Operations Research https://doi.org/10.1051/ro/2021109 www.rairo-ro.org A FUZZY DEMATEL APPROACH FOR EVALUATING THE RISK FACTORS (CASE STUDY: THE INSTRUCTION CENTER OF IRAN’S NATIONAL OIL COMPANY) Mohammad-Bagher Fakhrzad ∗ , Mohammad-Reza Firozpour and Hasan Hosseini Nasab Abstract. Many risk factors are dependent on each other and taking this into account can be helpful in managing appropriate decisions. The poor evaluation of these factors will impose high costs in many real applications especially for a supply chain. There are different methods for risk evaluating and their effects for ranking them. For instant, in fuzzy DEMATEL method, the experts’ linguistic opinions and preferences on the agent effects are used as the input. The important point is how these opinions are aggregated to produce less computational error. In this regard, this paper proposes a new method based on statistical inferences for a fuzzy DEMATEL approach for evaluating the factors of a supply chain. This method was applied to a case study and the results showed that the proposed method was better than other methods for integrating the experts’ opinions in a supply chain. However, this method was proposed for the evaluation of supply chain factors, it can be applied to other systems as well. Mathematics Subject Classification. 62A86, 91G70. Received July 6, 2020. Accepted July 21, 2021. 1. Introduction Many factors such as international competitors, demanding customers and rapid technological change pro- foundly impact the markets. Therefore, successful competition in this environment requires reducing operational costs and enlarging profit margins. For most industrial firms, the purchasing of raw material and component parts from suppliers constitutes a major expense. Hence, among the various strategic activities involved in the supply chain management, the purchase decision has profound impacts on the overall system [34]. When supply chain is faced with risk events, selecting the right suppliers becomes more essential than ever for the business. Several factors such as unquantifiable information, incomplete information, unobtainable information and partial ignorance cause the imprecision in decision making. Since conventional MADM methods cannot effectively handle problems with such imprecise information, therefore fuzzy multiple attribute decision-making methods have been developed owing to the imprecision in assessing the relative importance of attributes and the performance ratings of alternatives with respect to attributes [10]. Decision-Making Trial and Evaluation Labo- ratory (DEMATEL) is a widely used method to analyze and visualize the structure of complex systems through Keywords. Supply chain, fuzzy DEMATEL, experts’ linguistic preferences, agent ranking. Department of Industrial Engineering, Yazd University, Yazd, Iran. * Corresponding author: mfakhrzad@yazd.ac.ir c  The authors. Published by EDP Sciences, ROADEF, SMAI 2021 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.