The success of transdisciplinary approaches to address sustainability problems largely depends on the compatibility between the research stances of the researchers involved. A research stance is the strategy used to deal with an indeterminate situation, and influences choices at all steps in knowledge production, such as defining a problem in scientific terms or selecting methods. These choices encompass epistemology, methodology and implementation. We present a heuristic tool for researchers to reflect on the choices that define their own research stances. Designed and tested as part of doctoral training, this tool uncovers how research choices can lead to a wide range of research stances about a situation that requires action. Our tool allows researchers to articulate and discuss their research stances, to facilitate their management within a project. It is also useful to understand the relevance for action of the knowledge they generate.