Each year several hundred New Zealand student teachers complete a final practicum before graduating to take on the critical role that teachers play in children’s learning. This final practicum is crucial to determining the student teacher’s suitability for entry into the profession. However, assessment of student teachers’ competence during the practicum appears to be particularly challenging, as making judgments about complex performance, such as teaching, is a sophisticated process. In this article we draw on findings from a 2-year Teaching and Learning Research Initiative project that investigated how we make authentic practice-based judgments about student teachers’ readiness to teach.