This paper reviews the place of the therapeutic community in the mental health field, using a sociological framework to understand some key factors that have shaped the field and its response to this approach to therapy. The therapeutic community treatment method in mental health has been contested over the years. It has challenged conventional professional frameworks, it has dealt with a difficult client group, and it has been hostile to or at least awkward about establishing its evidence base. In this paper I reflect on the ‘politics of evidence’ in contested fields. I draw on the analysis of ‘fields’ from the work of French sociologist Pierre Bourdieu, and the analysis of scientific knowledge from an area of the social study of science, ‘actor-network theory’. I argue that evidence is not neutral in contested fields, and that the technology of trials is not balanced with a theoretically informed understanding of the phenomena under scrutiny (causality versus meaning).