Paper by Mareike Blum: “In sustainability research, knowledge co-production can play a supportive role at the science-policy interface (Norström et al., 2020). However, so far most projects involved stakeholders in order to produce ‘useful knowledge’ for policy-makers. As a novel approach, research projects have integrated randomly selected citizens during the knowledge co-production to make policy advice more reflective of societal perspectives and thereby increase its epistemic quality. Researchers are asked to consider citizens’ beliefs and values and integrate these in their ongoing research. This approach rests on pragmatist philosophy, according to which a joint deliberation on value priorities and anticipated consequences of policy options ideally allows to co-develop sustainable and legitimate policy pathways (Edenhofer & Kowarsch, 2015; Kowarsch, 2016). This paper scrutinizes three promises of involving citizens in the problem framing: (1) creating input legitimacy, (2) enabling social learning among citizens and researchers and (3) resulting in high epistemic quality of the co-produced knowledge. Based on empirical data the first phase of two research projects in Germany were analysed and compared: The Ariadne research project on the German Energy Transition, and the Biesenthal Forest project at the local level in Brandenburg, Germany. We found that despite barriers exist; learning was enabled by confronting researchers with problem perceptions of citizens. The step when researchers interpret and translate problem frames in the follow-up knowledge production is most important to assess learning and epistemic quality…(More)”.