Representing reuse in the circular economy: a study of circularity indicators

Reuse is widely regarded as a primary strategy to mitigate plastic packaging waste, occupying a higher position than recycling in the waste hierarchy. However, most existing circularity indicators do not include reuse or include it only as an inferior circularity strategy. This paper evaluates how existing circularity indicators applicable to packaging integrate reuse in their calculation methods and results. A literature review identified 88 circularity indicators, which were filtered to 11 based on active usage and packaging relevance. These 11 indicators were analysed against the ISO 59004:2024 circularity framework using a scoring matrix. The four most relevant indicators (Material Circularity Indicator, Product Circularity Indicator (PCI), Eco-efficient Value Ratio and UP Scorecard) were evaluated using a comparative assessment of a reusable plastic container. Three key variables were tested: recycled content, recycling rate, and number of reuses. No single indicator performed best across all three assessment methods. While combining PCI and the UP Scorecard provides the most thorough assessment currently available, this combination still fails to fully capture sensitivity to varying levels of reuse. Future circularity indicators must evaluate both the level and operational feasibility of reuse, rather than relying on binary inclusion.