Circularity is often treated as a design principle or strategic ambition to improve resource efficiency, but in practice, many of its claims remain unverified and untraceable. Existing assessment methods typically focus on intended design strategies or modelled impacts, rather than demonstrating real-world outcomes. This paper introduces the concept of evidence-based circularity assessment as an alternative approach for shifting from intention to actionable outcome. Drawing on an analogy of two contrasting ‘circular’ coffee pod systems, it illustrates how the credibility of circularity claims depends on the presence of verifiable evidence, coordinated infrastructure, and traceable processes. Building on these insights, the paper proposes a conceptual framework for assessing circularity, structured around three interdependent elements: proof, process, and persuasion. Finally, the paper explores how these principles can be applied in the built environment, where supporting systems are needed to track, evaluate, and realize circular material flows. The approach aspires to support more transparent, accountable, and adaptive forms of circularity assessment in complex real-world settings.

Reimagining design as a transformative practice for realizing a circular built environment is both urgent and important. Many of today's resource problems can be traced back to the way constructions are being designed. The adoption of circular design practices may alleviate these problems. Most previous research has either mapped the boundaries of contemporary circular design practices or pushed those boundaries with new interventions. The lived experiences of designers are, however, often overlooked. Little remains known about what it is like to be engaged in and how to ‘live through’ circular design. This study therefore seeks to understand the practice from the perspective of designers themselves. Through applying an interpretative phenomenological analysis to unstructured interview data collected from ten frontrunning Dutch designers, it explores both the what and how of circular design. Four emergent themes were found that illuminate the experience itself. Circular design is, accordingly, interpreted as a practice which: proclaims responsibility towards the Earth, materializes future-oriented solutions, deals with a multi-headed monster, and involves orchestrating a design ecosystem. These themes are illustrated with narrative accounts of designers' actual experiences. The rich, in-depth insights offer ample learning opportunities to better understand and facilitate unfolding circularity transitions. Circular design is, as such, theorized as a vital practice that can shape the built environment through materializing responsible futures.

Deze leidraad gaat over circulair ontwerpen, hét moment waarin circulaire ambities vorm krijgen. De keuzes die dan worden gemaakt, hebben immers een grote invloed op het resultaat. Maar dan moeten we er natuurlijk wel voor zorgen, dat de juiste keuzes worden gemaakt. En ook moeten alle betrokkenen bij het ontwerpproces dezelfde doelen en dezelfde oplossingen nastreven. Het zal duidelijk zijn dat goede afspraken hierover de ruis in de communicatie aanzienlijk vermindert en er uiteindelijk een effectiever ontwerpproces ontstaat. Met deze leidraad ‘Circulair ontwerpen’ leggen we die afspraken vast. Het gaat daarbij om afspraken die geschikt zijn voor de bouwsector in de breedte (woning- en utiliteitsbouw en GWW/infra), met, waar relevant, specificering naar de deelsectoren. En ook om afspraken die zich niet alleen richten op ontwerpers maar ook op alle andere rollen die een bijdrage kunnen of moeten leveren aan een circulair ontwerp en de realisatie daarvan. De afspraken aan ontwerpers moeten uiteraard voldoende vrijheid geven en geen belemmering vormen voor innovatie.