The transition towards sustainable societies necessitates inter- and transdisciplinary knowledge, particularly in urban planning, where diverse knowledge traditions are crucial for decision-making. Despite this, planning practices often remain entrenched in institutional and legal frameworks that hinder the integration of multiple ways of knowing and undervalue lay knowledge. Researcher-led urban innovation processes are increasingly adopting experimental approaches for the multi-stakeholder co-creation of knowledge, addressing urban challenges through interdisciplinary approaches. This article addresses the interdisciplinary collaboration between researchers in experimental urban planning processes by examining a research project that focused on participatory environmental co-monitoring and planning for urban air quality in Nordic contexts. The study builds a bridge between theories of interdisciplinarity, urban experimentation, and planning theory. By presenting urban living labs (ULLs) as arenas for co-learning that integrate scientific and lay knowledge, the article explores how planning researchers can facilitate mutual learning and navigate the micropolitics of knowledge co-production. We develop the concept of cross-disciplinary unknowns to highlight the dynamics and challenges in research teams with diverse epistemological backgrounds. We argue that an explicit and structured approach for explicating epistemological differences can facilitate the detection of unreflected knowledge retention between disciplines.
Steffansen et al. (2026) studied this question.