On which common ground to build? Transferable knowledge across cases in transdisciplinary sustainability research.

To support societal problem solving, transdisciplinary research (TDR) uses knowledge co-production focusing on relevance and validity in a studied case and its particular social-ecological context. In the first instance, the resulting situated knowledge seems to be restricted to these single cases. However, if some of the knowledge generated in TDR could be used in other research projects, this would imply that there is a body of knowledge representing this special type of research. This study used a qualitative approach based on the methodology of grounded theory to empirically examine what knowledge is considered transferable to other cases, if any. 30 leaders of 12 Swiss-based TDR projects in the field of sustainable development were interviewed, representing both academia and practice. The transferable knowledge we found consists of the following: (1) Transdisciplinary principles, (2) transdisciplinary approaches, (3) systematic procedures, (4) product formats, (5) experiential know-how, (6) framings and (7) insights, data and information. The discussion of TDR has predominantly been focusing on transdisciplinary principles and approaches. In order to take knowledge co-production in TDR beyond an unmanageable field of case studies, more efforts in developing and critically discussing transferable knowledge of the other classes are needed, foremost systematic procedures, product formats and framings.