In this contribution, we highlight a collaborative research group that focuses on internship supervisors. For the past three years, participants have been questioning the process of co-evaluating internships in teacher training institutions. Our aim is to show how the sharing of representations on the subject under investigation, the co-evaluation of internships, the co-construction of a common definition and the collegial analysis of data from participants’ practices affect the “quality” of collaborative research. More specifically, we attempt to identify the advantages and obstacles to working on an object related to evaluation “in collaboration” within a collaborative research project.