Fuzzy DEMATEL with ranking based on degree of optimism for supplier selection criteria in fertigation system / Asyura Abd Nassir, Nazirah Ramli and Roselah Osman

Supplier selection is a critical factor in the success of fertigation systems, which integrate irrigation and fertilization to enhance agricultural productivity. This process's inherent uncertainty and complexity necessitate decision-making methodologies considering human judgment and risk preference factors. This study proposes the fuzzy DEMATEL method with a ranking based on the degree of optimism to evaluate and prioritise supplier selection criteria in fertigation systems. Six experts were involved in evaluating the influence of criteria such as price, quality, delivery, public procurement policy, technical, and managerial. The proposed method consists of 11 steps, includingdeveloping a fuzzy direct-relation matrix, average matrix, normalised fuzzy direct-relation matrix, fuzzy total relation matrix, and ranking based on left and right integral value. The left integral value represents the decision maker's perspective that is more inclined towards pessimism, while the right integral value represents the perspective that is more inclined towards optimism. The proposed method is implemented in the selection of supplier criteria in the fertigation system at one branch of RISDA (Rubber Industry Smallholders Development Authority) on the East Coast of Malaysia. The findings reveal that technical and quality criteria are paramount, though their relative importance shifts depending on the decision-maker’s degree of optimism. Specifically, technical criteria are prioritised by neutral and optimistic decision-makers, while quality criteria are regarded as most important by pessimistic decision-makers. Furthermore, the study identifies public procurement policy and technical criteria as part of the causal group, significantly influencing other criteria such as price, delivery, and managerial factors. The results align with previous research, confirming the consistency aspect of the fuzzy DEMATEL method with a degree of optimism-based ranking. This approach provides a comprehensive decision for agricultural decision-makers, facilitating more greater knowledge and balanced supplier selection decisions.