A Standards-Guided Approach to Formalizing
Product Circularity Assessment Metrics
Junwon Ko
1(
B
)
, Sandwana Sneethan
1
, Gisele Bortolaz Guedes
1
,
Fazleena Badurdeen
1
,I.S.Jawahir
1
, Buddhika Hapuwatte
2
, and K. C. Morris
2
1
Institute for Sustainable Manufacturing (ISM) and Department of Mechanical and Aerospace
Engineering, University of Kentucky, Lexington, KY, USA
jko248@uky.edu
2
National Institute of Standards and Technology (NIST), Gaithersburg, MD, USA
Abstract. The industrial transition towards a more sustainable Circular Econ-
omy
(CE) emphasizes the need for products that align with CE principles and
robust methods for assessing how circular they are. However, ambiguities between
metrics vs. indicators are not yet addressed in the current discussion of product
circularity assessment (PCA). Most PCA methods also lack clarity in the met-
rics used, including their selection and description, which leads to confusion and
limited industry adoption. To address these gaps, this paper proposes clear defini-
tions for indicators and metrics and adapts standards to establish a structured
approach for developing PCA metrics. This process involves establishing the
objective or purpose of each metric, identifying candidate metrics from literature
sources or existing PCA methods, and defining them with detailed context (e.g.,
description, formula, range) and content information (e.g., notes, references, stan-
dards/guidelines). To effectively compile and communicate the developed metrics,
an Excel-based database consisting of attributes, indicators, and metrics (AIM)
was developed and presented. Over 80 relevant metrics for measuring product
circularity were identified, characterized, and organized under the AIM database.
The standards-guided approach and database proposed in this paper formalize the
development of metrics for PCA and aid data collection processes, enhancing their
practical application in the industry. The findings in this paper further contribute
to the successful transition toward product-level CE.
Keywords: Circular Economy · Product Circularity · Indicators · Metrics
1 Introduction
The extraction and processing of resources are continuously increasing to meet the
demands of a growing population. These resources are currently extracted, processed,
consumed, and disposed of in a manner that leads to the triple planetary crisis: climate
change, biodiversity loss, and pollution [1]. Circular Economy (CE) addresses this prob-
lem
by establishing closed-loop flows of resources through value recovery, retention, and
enhancement [2]. In CE, restoration and regeneration practices avoid the loss of value
and
materials at end-of-life (EoL). Restoration focuses on maximizing the lifespan of
© The Author(s) 2025
H. Kohl et al. (Eds.): GCSM 2024, LNME, pp. 864–872, 2025.
https://doi.org/10.1007/978-3-031-93891-7
_95
Full citation:
Ko, J. et al. (2025). A Standards-Guided Approach to Formalizing Product Circularity Assessment Metrics.
In: Kohl, H., Seliger, G., Dietrich, F., Vien, H.T. (eds) Decarbonizing Value Chains. GCSM 2024.
Lecture Notes in Mechanical Engineering. Springer, Cham. https://doi.org/10.1007/978-3-031-93891-7_95
