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A taxonomy of circular economy indicators
Michael Saidani, Bernard Yannou, Yann Leroy, François Cluzel, Alissa Kendall
TL;DR
Circularity indicators are needed to monitor CE progress, yet their varied scopes and purposes are difficult to interpret amid multiple CE definitions. The paper systematically reviews and classifies available indicators, identifying 55 sets and linking them to a user-oriented selection tool. Its taxonomy clarifies indicator characteristics and supports appropriate use while highlighting data and industrial-uptake challenges.
Problem
The growing number of C-indicators have inconsistent scopes, purposes, and applications, making their measurement targets and appropriate uses unclear.
Method
The paper conducts a systematic review of academic and grey literature, analyzes 55 C-indicator sets, and organizes them into a taxonomy with a linked selection tool.
Results
The analysis identifies 55 sets of C-indicators and classifies them across circularity-related criteria, including implementation level, loops, performance, and circularity perspective.
Takeaways & Limitations
The taxonomy and selection tool provide a structured way to clarify and select C-indicators for CE monitoring and implementation.
Takeaways & Limitations
The tool and indicator uptake remain constrained by the need to keep the database current and by substantial data requirements across value chains.
Abstract
from arXiv · showhide
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.
1. INTRODUCTION
Circularity indicators are needed to monitor CE progress, but their growing number and varied scopes make their purposes difficult to interpret. This article responds with a user-oriented taxonomy and selection tool to clarify their utility.
- CE indicators are increasingly needed to measure and monitor progress toward a circular economy.
- Existing indicators vary in scope, purpose, and application, while differing CE definitions make their intended measurement unclear.
- The article develops a taxonomy and associated selection tool to organize C-indicators for industrial and policy users.
- The study identifies the need to clarify indicator utility and support appropriate selection as the CE measurement field expands.
2. DEFINITION OF TERMS – POSITIONING FOR THIS STUDY
The paper positions CE as a multifaceted concept whose measurement requires explicit terminology. It adopts working definitions for CE, indicators, and taxonomy-related terms to support its classification.
- CE is defined as an economic system replacing end-of-life with reducing, reusing, recycling, and recovering materials across micro, meso, and macro levels.
- The CE definition used here aims at sustainable development through environmental quality, economic prosperity, and social equity.
- An indicator is adopted as a quantitative or qualitative factor that measures achievement, reflects intervention-related change, or assesses performance.
- The paper privileges “indicator” over related terms such as measures, metrics, index, and indices because they are commonly used interchangeably.
- Taxonomy is preferred for the paper’s empirical classification of C-indicators, while typology emphasizes sorting groups by similar features.
3. MATERIALS AND METHODS
The study uses a systematic extended literature review, supplemented by searches for sustainability and eco-design taxonomies. It identifies and analyzes C-indicators to build a practical classification.
- The research method is a systematic and extended literature review designed to synthesize literature, identify gaps, and highlight emerging patterns.
- Searches combined CE and measurement terms across title, abstract, and keyword fields in academic and non-academic databases.
- The review covers English-language C-indicator publications from 2010 through May 2018.
- A supplementary survey searched taxonomy, typology, classification, sustainability, and eco-design literature for design inspiration.
- 55 sets of C-indicators were identified from journal articles, conference papers, a thesis, technical reports, and websites or tools.
- The collected indicators were analyzed by their features, principles, and applications to structure a classification supporting practical selection and use.
4. LITERATURE BACKGROUND – STATE-OF-THE-ART
Prior research developed diverse circular economy indicators and classification approaches, but their variety created a need to clarify what they measure and how they should be used. Existing work spans indicator purposes, sustainability dimensions, eco-design tools, circular business models, design strategies, and circular economy loops.
- Indicators can summarize complex information and support circular economy performance measurement.
- Circular economy indicators can benchmark industries, inform consumers, support regulation, and capture reuse and recycling stakes.
- Sustainability indicators: Sustainability-indicator taxonomies classify indicators by dimensions such as measurement aspects and development techniques.
- Eco-design tools: Eco-design tool classifications distinguish assessment and improvement functions and organize tools by properties including complexity, type, and main function.
- Circular economy approaches: Existing circular economy research classifies business models, circular design strategies, and loop-related assessment purposes such as evaluation, ranking, implementation, and monitoring.
- Circular economy indicators: A review of 55 sets of circular economy indicators provides a basis for characterizing and classifying the field.
5. TAXONOMY AND SELECTION TOOL OF C-INDICATORS
The paper proposes a need-based taxonomy and selection tool to clarify and guide the use of 55 sets of circular economy indicators across different implementation levels, loops, performance perspectives, and applications.
- Taxonomy and selection tool: The taxonomy classifies more than 50 sets of C-indicators into 10 categories based on their purposes, scopes, usages, CE principles, and indicator characteristics.The associated databank contains 55 sets and supports indicator selection according to user needs.
- CE implementation levels: C-indicators are differentiated by implementation level, including micro organizations, products and consumers; meso symbiosis associations and industrial parks; and macro cities, regions and countries.The three levels require indicator frameworks suited to national, regional, and local CE performance measurement.
- CE characteristics: The taxonomy distinguishes indicators according to CE loops, circularity performance, and circularity perspective, including maintain or prolong, reuse or remanufacturing, recycling, intrinsic or consequential circularity, and potential or effective circularity.It separates inherent circularity from consequences such as sustainability effects and distinguishes projected potential circularity from observed circularity.
- Observed patterns: 90% of reviewed micro-level indicator sets include recycling, 65% include remanufacturing and/or reuse, and 45% explicitly include all main CE loops.Macro-level indicators, mainly developed in China, focus more strongly on recycling than on other CE loops.
- Observed patterns: 80% of micro-level C-indicators evaluate intrinsic circularity, 40% examine sustainability impacts, and only 20% include both simultaneously.Economic and environmental impacts are more commonly represented than social consequences.
- Observed patterns: 60% of micro-level sets aggregate circularity into a single indicator, 17 of 20 are generic, and 45% are linked to computational tools.Most remain in a pilot phase and have been applied or tested on only one product or industrial sector; the selection databank can be updated as new indicators emerge.
6. DISCUSSION
The discussion finds progress in micro-level circularity assessment while emphasizing unresolved challenges in indicator comprehensiveness, data availability, industrial uptake, and taxonomy flexibility. It also proposes extensions to make indicators more useful across life-cycle stages, design processes, material loops, and system sizes.
- Progress at the micro-level and complementarity between C-indicators: Micro-level C-indicators have become more prevalent, challenging earlier claims that product, supply-chain, and service circularity were rarely measured.The authors contrast their findings with 2017 statements that deep research on micro-level CE assessment was still lacking.
- Progress at the micro-level and complementarity between C-indicators: No single indicator captures all CE requirements, so combining indicators can address both intrinsic circularity and wider sustainability effects.Examples include pairing longevity with circularity measures and complementing physical indicators with monetary ones.
- Current limits and potential solutions: data issue and industrial uptake: Data collection across the value chain remains a major barrier because information can be difficult, costly, time-consuming, confidential, and dependent on business-to-business exchange.Digital technologies such as the Internet of Things may generate new micro-level data, but measurement for improvement remains experimental.
- Areas of improvement and flexibility of the proposed taxonomy: The taxonomy is designed as a practical and understandable classification rather than a completely exhaustive system, leaving room for complementary categories.Its ten categories cover CE features, indicator uses, and assessment-framework characteristics.
- Areas of improvement and flexibility of the proposed taxonomy: Potential extensions include life-cycle-stage reporting, guidance for industrial design steps, preparation and implementation times, material-loop quality, and intensive-versus-extensive indicator properties.Intensive indicators are preferable for comparisons across countries, regions, cities, and sectors, while extensive indicators require normalization.
- Areas of improvement and flexibility of the proposed taxonomy: Because CE transitions and stakeholder needs evolve, the characterization of C-indicators should be regularly updated and monitoring frameworks should remain flexible.Future work should also establish links and correlations among existing indicators.
7. CONCLUSION AND PERSPECTIVES
The article clarifies the purposes and appropriate uses of circularity indicators through a taxonomy and selection tool, while identifying requirements for their evaluation, adoption, and implementation. It also emphasizes that indicators support—but do not alone accomplish—the broader circular economy transition.
- Contribution: The taxonomy organizes 55 sets of circularity indicators to clarify their purposes and support appropriate use by industrial practitioners and policy-makers.An associated user-friendly selection tool supports indicator choice for CE-related projects.
- Perspectives: The taxonomy is presented as a baseline for future research on more robust indicators, their industrial adoption, and their contribution to the CE transition.Further work should investigate indicator quality and uncertainty more objectively.
- Further evaluation: Objective evaluation of indicator definition, relevance, scientific soundness, and uncertainty is identified as a priority for increasing trust and confidence in their use.Suggested criteria include clarity, representativeness, interpretability, comparability, repeatability, and scientific grounding.
- Further uptake: Organizing indicators understandably could support their uptake by industry and their use by policy-makers to monitor CE-related regulatory frameworks.Indicators can help track transition progress and provide direction, while sector-specific development may foster adoption.
- Further uptake: Effective use requires indicators to be intelligible to their recipients and translated into precise actions or practical recommendations.The paper also calls for links between circularity heuristics and more tangible impacts.
- Further implementation: C-indicators are only one element of CE implementation, which also relies on product design, business models, reverse logistics, enablers, and system conditions.Their information must be translated into suitable actions, alongside complementary tools and resources such as organizational models, technologies, and shared knowledge.
APPENDIX A - NOMENCLATURE OF THE C-INDICATORS REVIEWED
The appendix provides the nomenclature and sources for the 55 circularity-indicator sets reviewed in the taxonomy, with related supplementary materials available online.
- Nomenclature: Table A.1 lists the 55 circularity indicators reviewed in the proposed taxonomy, including their acronyms and sources.
- Supplementary material: The complete taxonomy and its associated Excel-based selection tool are available as supplementary online material.