Assessment is a significant issue for learning in the workplace. In some professions there are key indicators of success shared by workplace and academic supervisors alike. Beyond specific professions, however, assessment becomes more diffuse in workplaces that do not have explicit criteria established to judge performance of students in experiential learning. Assessing learning in these workplaces may be associated with methods that rely more upon student self appraisal and workplace supervisor reports. This paper reports on the approach used for assessment in a public policy internship program in on Australian University--Deakin University in Victoria. It is argued that assessment, rather than being an add-on or a test of pre-ordained information, is central to the process of learning itself. This means that before students embark upon a policy internship they need to build their critical thinking abilities; i.e. a process of purposeful, self-regulatory judgement. Secondly they need to discuss how to negotiate their tasks in different workplaces and how to produce the criteria to be used in their evaluation.