A design rationale is a representation of the reasoning behind a design concept, explaining why the solution is designed the way it is. This makes design rationale a critical part of concept development. However, there is little exploration on how to build a design rationale. This study sheds light on professional designers’ reasoning in conceptual design, as we examine how design rationales for different concepts are built based on a longitudinal study in the context of two design studios. Particularly the study provides insight into how a design rationale is initiated, matured and finalized.@en

Value preservation is key for the transition from a linear economy to a sufficiency-based circular economy. However, to keep the value of products and materials at the highest level possible over time, different actors such as businesses, designers, consumers, and policymakers must know when value is reduced during a product's lifetime, and how to capture and preserve this value. This study results in a comprehensive mapping of factors with a negative impact on the perceived value of products from a consumer's perspective and suggests new routes to value preservation, as a way of turning the negative factors into positive changes. Next, the paper presents a conceptual model for value preservation. The model identifies new key actors: value transformers (product developers), value co-operators (consumers), value gatekeepers (businesses), and value accountants (policymakers) and suggests important changes to their linear practices, which are needed for the sufficiency-based circular economy paradigm to flourish.@en