This article aims to highlight how a scientific and critical approach is used in assessment dialogues during the last period of a practical, school-based teacher education programme. The result is based on 13 assessment dialogues conducted in a course at a Swedish university, where one of the course objectives is to, 'in a scientific way, analyse teaching situations based on learning theories'. The assessment dialogues were analysed drawing from Bernstein's concepts of 'classification', 'framing', 'horizontal knowledge' and 'vertical knowledge'. The result shows that only in a minority of the assessment dialogues are students expected to use theory as an analytical tool and to critically examine their teaching practice. The theory is used in a more instrumental way to legitimize what is considered the 'right way' to teach. One conclusion is that the critical tradition of academia is seldom observed despite being clearly stated in the learning goals. The link between general academic knowledge and more school-based contextual knowledge is often missing or not made visible by the students or the teacher educators, and normative content is still clearly prominent.