Dissertation defenses are ambiguous affairs, which mark both the end of a long process of doctoral education and the inauguration of a doctoral candidate into a body of experts. At Maastricht University (and other Dutch universities), the decision to award a doctoral degree is made on the basis of the written dissertation well before the defense, which makes the ambiguous status of the event between examination and celebration especially evident. Nevertheless, participants attach importance to the event because it impacts the reputation of individual researchers, as well as that of research groups and of the host-university itself. Taking a Goffmanian perspective on the event as a performance, it becomes clear that the ambiguity in the definition between celebration and assessment is contained within the script that details how the performance should be conducted. In this script, participants' role is unclear, providing them the means to act in accordance with their own definition of the event. The ambiguous definition of the event is performed at an individual level but also in team performances, in which participants correct each other when someone's behavior appears too celebratory. Amidst this ambiguity between celebration and assessment, the university reinforces its own authority to award doctoral degrees, acting as a gate-keeping institution to the academic world.