Abstract
While circular economy adoption is growing worldwide, its systematic assessment remains a challenge. This paper aims to shed light on the strengths and weaknesses of firm-level circular economy assessment tools and to theorize on the circular economy assessment issue. Four tools were selected and compared based on a qualitative comparative analysis as well as on their practical application to multiple case studies. The originality of this comparison lies in evaluating the extent to which these tools are affected by ontological and etymological issues and by epistemological and human cognitive bias. Such an evaluation was based on seven criteria rooted in the interpretivist research paradigm and grounded theory methodology. The results indicate that, albeit providing circular economy awareness and insights on high-level strategic circular economy practices, the tools can be improved in terms of transferability, credibility, confirmability, fit, and generality. Current holistic tools fail to consider some firms' specificities and to provide circular economy implications, besides being subject to user manipulation due to issues such as low reliability and human bias. Accordingly, the study provides suggestions to improve the development of future circular economy assessment tools and enhance practitioners' awareness of the effective use of these tools, having both academic and practical implications.