The aim of this dissertation is to explore some of the problems associated with introducing authentic assessment in teacher education. In the first part of the dissertation the question is investigated, through a literature review, whether the use of scoring rubrics can aid in supporting credible assessment of complex performance, and at the same time support student learning of such complex performance. In the second part, the conclusions arrived at from the first part are implemented into the design of the so-called “Interactive examination” for student teachers, which is designed to be an authentic assessment for teacher competency. In this examination, the students are shown short video sequences displaying critical classroom situations, and are then asked to describe, analyze, and suggest ways to handle the situations, as well as reflect on their own answers. It is investigated whether the competencies aimed for in the “Interactive examination” can be assessed in a credible manner, and whether the examination methodology supports student learning. From these investigations, involving three consecutive cohorts of student teachers (n = 462), it is argued that three main contributions to research have been made. First, by reviewing empirical research on performance assessment and scoring rubrics, a set of assumptions has been reached on how to design authentic assessments that both support student learning, and provide reliable and valid data on student performance. Second, by articulating teacher competency in the form of criteria and standards, it is possible to assess students’ skills in analyzing classroom situations, as well as their self-assessment skills. Furthermore, it is demonstrated that by making the assessment demands transparent, students’ performances are greatly improved. Third, it is shown how teacher competency can be assessed in a valid way, without compromising the reliability. Thus the dissertation gives an illustration of how formative and summative purposes might co-exist within the boundaries of the same (educative) assessment.