This paper adopts a conversation analysis perspective towards assessments, in encounters between West African migrants, representatives of institutions, and mediating interpreters in healthcare settings in Italy. It argues that in mediated encounters, assessments of actions and behaviours provide a means whereby participants orient to their institutional roles, since an assessment implies both an understanding of what is evaluated and the right to evaluate it. Evaluative sequences (assessment followed by reaction to the assessment) display how such understandings and rights are negotiated, and thereby reflect and reflexively construct participants’ institutional roles. In particular the mediator’s identity as a ratified participant can be seen to be jointly constructed through the use of assessments.