Managing a decision-making method: examining large groups with high conflict

Purpose To address interest conflicts in large-scale group decision-making (LSGDM) and overcome the limitations of the DEMATEL method regarding expert heterogeneity and slow consensus convergence, this study proposes an improved DEMATEL to enhance the efficiency and quality of complex decisions. Design/methodology/approach An integrated DEMATEL method for high-conflict LSGDM has been developed. This method includes: (1) reducing system complexity through hierarchical decomposition and identifying interest subgroups through clustering, (2) expert opinions are extracted through the basic probability assignment (BPA) function, weights and reliability are automatically calculated, and evidence fusion is performed using the analytical generalized combination (AGC) rule, (3) designing a semi-automatic opinion correction mechanism based on trust to accelerate consensus reaching and (4) establishing a multi-objective programming model to coordinate conflicts among subgroups. Findings The proposed DEMATEL method excels in handling highly conflicting and unstructured opinions. Its dynamic weight and reliability mechanism accurately integrates high-quality inputs, while the trust-based consensus correction mechanism enhances convergence speed. The “intra-subgroup consensus, inter-subgroup coordination” framework improves group acceptance. Furthermore, expert judgment requirements are reduced by 34%–72%, significantly improving efficiency. Originality/value This study extends DEMATEL to high-conflict LSGDM. The proposed consensus and coordination model provides a solution approach for managing complex conflicts.