A Hybrid Quadripartitioned Single-Valued Neutrosophic Method and its Application for the Selection of Emergency Logistics Outsourcing Suppliers

The selection of an emergency logistics outsourcing supplier (ELOS) is critical for enhancing disaster response efficiency, reducing operational costs, and strengthening supply chain resilience. A scientifically robust supplier evaluation framework optimizes resource allocation, mitigates risks, and ensures timely material distribution, serving as a cornerstone of effective emergency management systems. This study introduces a novel hybrid quadripartitioned single-valued neutrosophic (QSVN) multi-criteria decision-making (MCDM) approach, integrating the coefficient of variation method (CVM) and complex proportional assessment (COPRAS) to address ambiguity and uncertainty in decision-making. Key contributions include: (1) establishing QSVN Aczel-Alsina operational rules based on Aczel-Alsina norms, (2) developing weighted averaging and geometric Aczel-Alsina aggregation operators for QSVN numbers (QSVNNs), and (3) proposing a hybrid CVM-COPRAS framework for criteria weighting and alternative ranking. A case study on ELOS selection validates the method’s efficacy, supported by sensitivity and comparative analyses demonstrating its robustness and superiority over existing techniques. The results confirm the model’s stability and improved performance in complex decision-making under uncertainty.