A comprehensive comparative analysis of water use efficiency in OECD countries using hybrid MCDM models and weighting frameworks

Decisions regarding the sustainable management of ecosystems are shaped by multifaceted sustainability criteria encompassing environmental, social, and economic dimensions. Therefore, decision-makers need analytical methods that consider multiple criteria in complex areas such as water use management. This study conducts a comprehensive analysis using four Multi-Criteria Decision Making (MCDM) techniques—ARAS, MARCOS, CODAS, and COPELAND—to assess the water use performance of OECD countries under resource pressure. Seven indicators were used to measure performance, covering industrial, agricultural, and service water efficiency, as well as water stress and freshwater and agricultural withdrawal rates from total renewable water resources. 2020 data for all indicators were obtained from the FAO database. One of the unique aspects of the study is the use of three different scenarios for weighting the criteria: (i) the Equal Weight Scenario, which assigns equal importance to all criteria, (ii) the Entropy Scenario, which is based on data variance, and (iii) the AHP Scenario, which is based on expert judgement. These scenarios were created to test the sensitivity of country performance rankings to weighting. Spearman correlations ranged from 0.96 to 0.99 and were significant (p<0.01); while the top 5 countries were maintained in all three weighting scenarios (e.g., Luxembourg: 1–1–1), more pronounced shifts were observed in the middle group (e.g., Türkiye: 29–24–26/24–29 band). Calculations were performed using the JMcDM package in the Julia programming language. While some ranking changes were observed across scenarios, overall strong consistency emerged between the top and bottom performance groups. Under all three weighting scenarios, the most successful countries were Luxembourg (1-1-1), Iceland (2-2-5), Denmark (3-4-4), the Netherlands (4-3-2), and Switzerland (5-5-3), while the lowest-performing countries were Mexico (38-38-38), Greece (37-36-35), Poland (36-37-36), Italy (35-30-27), and Chile (34-32-37). Türkiye (29-24-26), although showing little change across scenarios, ranked lower overall and is ranked between 24th and 29th out of 38 countries by method. These results indicate that countries' water use performance is generally resilient to the weighting approach, while the rankings of countries in the middle tier are more sensitive to the weighting model. The study demonstrates that scenario-based MCDM applications can provide valuable analytical input for policymakers in decision-making processes aimed at effective water resource management. • Water use sustainability in 38 OECD countries was assessed using four multi-methods sustainability assessment (ARAS, MARCOS, CODAS, and Copeland). • Luxembourg ranked 1st in all weighting scenarios, while Iceland, Denmark, the Netherlands, and Switzerland were among the highest-performing countries. • Spearman rank correlations between methods were above 0.96, indicating a high degree of consistency in the rankings. • Countries such as Turkey, Mexico, and Greece were in the lower performance group in all methods, pointing to structural water use inefficiencies. • The Julia-based JMcDM framework offers a transparent and applicable decision support approach for multi-method sustainability assessments.