Courses preparing early childhood professionals through institutes of technical and further education utilise competency standards to guide the assessment of students during professional experience. Some universities offering early childhood teacher education courses use the term "competencies" in practicum assessment forms and draw on teacher competency standards. This article explores how discourses of competence produced within positivist and liberal humanist discourses shape, guide and direct (govern) tertiary supervisors' beliefs about and understandings of the legitimacy of their professional judgement. Tertiary supervisors take up these discourses and use them as the basis upon which they govern themselves. The author argues that one of the effects of governmentality in this instance is that tertiary supervisors regulate and silence their professional judgement and defer to discourses of scientific rationality when assessing students on practicum placements. They produce assessment strategies that enable them to hide their subjective judgement within what appears to be a logical, rational and objective assessment process and position themselves as the rational, objective assessor, and, at the same time, the fair, responsible tertiary supervisor. (Contains 3 notes.)