A taxonomy of circular economy indicators

Implementing circular economy (CE) principles is increasingly recommended as a convenient solution to meet the goals of sustainable development. New tools are required to support practitioners, decision-makers and policy-makers towards more CE practices, as well as to monitor the effects of CE adoption. Worldwide, academics, industrialists and politicians all agree on the need to use CE-related measuring instruments to manage this transition at different systemic levels. In this context, a wide range of circularity indicators (C-indicators) has been developed in recent years. Yet, as there is not one single definition of the CE concept, it is of the utmost importance to know what the available indicators measure in order to use them properly. Indeed, through a systematic literature review-considering both academic and grey literature-55 sets of C-indicators, developed by scholars, consulting companies and governmental agencies, have been identified, encompassing different purposes, scopes, and potential usages. Inspired by existing taxonomies of eco-design tools and sustainability indicators, and in line with the CE characteristics, a classification of indicators aiming to assess, improve, monitor and communicate on the CE performance is proposed and discussed. In the developed taxonomy including 10 categories, C-indicators are differentiated regarding criteria such as the levels of CE implementation (e.g. micro, meso, macro), the CE loops (maintain, reuse, remanufacture, recycle), the performance (intrinsic, impacts), the perspective of circularity (actual, potential) they are taking into account, or their degree of transversality (generic, sector-specific). In addition, the database inventorying the 55 sets of C-indicators is linked to an Excel-based query tool to facilitate the selection of appropriate indicators according to the specific user’s needs and requirements. This study enriches the literature by giving a first need-driven taxonomy of C-indicators, which is experienced on several use cases. It provides a synthesis and clarification to the emerging and must-needed research theme of C-indicators, and sheds some light on remaining key challenges like their effective uptake by industry. Eventually, limitations, improvement areas, as well as implications of the proposed taxonomy are intently addressed to guide future research on C-indicators and CE implementation.

💡 Research Summary

The paper addresses the growing demand for tools that can measure and monitor the transition to a circular economy (CE), a concept increasingly promoted as a pathway to sustainable development. Recognizing that a multitude of circularity indicators (C‑indicators) have emerged from academia, consulting firms, and governmental agencies, the authors conduct a systematic literature review—including both peer‑reviewed and grey literature—to identify 55 distinct C‑indicator sets. They note that the lack of a unified definition of CE has resulted in a fragmented landscape of indicators whose purposes, scopes, and applications are often unclear.

To bring order to this diversity, the authors develop a need‑driven taxonomy comprising ten classification dimensions. The first dimension distinguishes the level of CE implementation: micro (product or process level), meso (industrial park or ecosystem level), and macro (city, region, nation). The second dimension categorises indicators according to the four CE loops—maintain, reuse, remanufacture, and recycle—reflecting where in the material life‑cycle the indicator focuses. The third dimension separates intrinsic performance metrics (e.g., material recovery rates, energy efficiency) from impact‑oriented metrics that capture broader environmental, social, or economic effects such as greenhouse‑gas reductions or resource‑depletion mitigation. The fourth dimension differentiates between actual (current) circularity and potential (future or target) circularity. Finally, the taxonomy addresses transversality by separating generic indicators applicable across sectors from sector‑specific ones tailored to particular industries. Additional sub‑criteria (time horizon, data accessibility, quantitative vs. qualitative nature) further refine the classification.

Building on this taxonomy, the authors compile the 55 indicator sets into a searchable Excel‑based query tool. Users can input criteria such as implementation level, CE loop, performance type, perspective, and sector specificity, and the tool instantly returns a shortlist of suitable indicators. This practical instrument is intended to streamline indicator selection for policymakers, corporate strategists, and researchers, reducing the time and expertise required to navigate the complex indicator landscape.

The paper also analyses why, despite the abundance of C‑indicators, their uptake in industry remains limited. Key barriers identified include high data collection costs, lack of standardised data formats, limited comparability across indicators, and insufficient policy or market incentives that would motivate firms to adopt circular metrics. Some indicators are overly specialised for niche sectors, while generic indicators may lack the granularity needed for detailed decision‑making.

To overcome these challenges, the authors propose several avenues for future work: (1) international and national standardisation of indicator definitions and data schemas; (2) development of digital platforms that enable real‑time data sharing and automated calculation of indicators; (3) integration of circularity metrics into policy instruments such as tax incentives, procurement criteria, or reporting mandates; and (4) fostering collaborative networks among academia, industry, and government to continuously validate, refine, and update the indicator set.

In conclusion, the study delivers the first comprehensive, need‑oriented taxonomy of circular economy indicators and couples it with a user‑friendly selection tool. By clarifying the purposes, scopes, and applicability of existing C‑indicators, the work helps bridge the gap between theoretical development and practical implementation, offering a solid foundation for future research and for the operationalisation of circular economy strategies across multiple systemic levels.