Circularity in Practice: Key Performance Indicators for Measuring, Managing, and Advancing Resource Efficiency

The transition towards a circular economy (CE) necessitates a fundamental re-thinking of how organizations measure, monitor and optimize sustainability per-formance. This paper explores the critical role of Key Performance Indicators (KPIs) in facilitating this transformation, providing a comprehensive taxonomy of circularity metrics across six domains: general, performance-based, material-related, energy-related, sustainability, and integrative indicators. The paper draws on recent academic and industry frameworks to present practical tools and meth-odologies for data collection, KPI implementation, and performance benchmark-ing. The role of digital technologies, including the Internet of Things (IoT), artifi-cial intelligence (AI), and blockchain, in facilitating high-resolution tracking and decision-making is emphasized. Furthermore, the paper addresses challenges in data integration, standardization, and sectoral applicability, particularly for small and medium-sized enterprises (SMEs). The discussion further explores chal-lenges in KPI adoption and identifies the need for optimization strategies. The ar-ticle's contribution lies in its provision of a structured approach for advancing sustainability and resource efficiency through robust KPI systems, by highlight-ing the synergies between measurement frameworks and circular business strate-gies. The analysis was supported by a pilot study conducted among representa-tives of the Polish small and medium-sized enterprise (SME) sector.