Operationalizing the Waste Hierarchy Though A Synthetic Performance Indicator: Evidence From Spain

Ensuring compliance with the European Union (EU) waste hierarchy is essential for advancing circular economy objectives and meeting legally binding municipal solid waste (MSW) targets. This study develops and applies the Waste Hierarchy Achievement Synthetic Indicator (WHASI), an innovative synthetic index designed to assess territorial performance in implementing the EU waste hierarchy. The proposed framework integrates Goal Programming (GP) with progressive penalty and bonus functions to capture non‐linear deviations from regulatory thresholds, combined with expert‐derived weights elicited through the Best–Worst Method (BWM). The empirical application covers the 43 counties of Catalonia (Spain) using 2023 data and four core indicators: prevention, recycling, energy recovery, and landfill disposal. Results reveal systematic non‐compliance, with an average WHASI value of −9.23 and substantial territorial heterogeneity. Prevention emerges as the principal structural bottleneck, accounting for nearly 60% of total index variation, as waste generation increased between 2011 and 2023 despite EU decoupling objectives. Approximately 70% of counties exhibit poor or critical performance. The findings underscore the limited effectiveness of downstream improvements in recycling or landfill diversion without structural progress in prevention. The WHASI framework provides a transparent and policy‐relevant tool for territorial benchmarking and supports differentiated governance strategies to achieve sustained alignment with EU waste legislation.