The popularity of the concept of evidence-based design (EBD) has exploded over the past five years, picking up speed as a topic of attention in environmental design conferences, papers and articles, and books. Rooted in the healthcare environment, the EBD concept has now bridged out to design of long-term care settings, housing and workplaces, as well as facilities management. While evidence-based design is indeed a seductive term for those of us interested in advancing research-informed design – portending linkages between research-derived evidence and environmental design – we cautiously note that, as of this writing, in its current conceptualisation, its clout is stronger than its clarity. This paper is a clarion invitation to the environmental design research community to consider the concept of evidence-based design as emergent, warranting careful, critical examination regarding its meaning and underlying assumptions.