A critical look at the content we select for teaching and the criteria for that selection may help us to establish a theoretical framework for studying the quality of teaching and learning. The discussion of such criteria is central to the German and Nordic didaktik tradition. The criteria for content selection reveal how educational content is related to student learning, and how the teacher appears a mediator of that relation. It reveals a distinction between an academic discipline and its corresponding educational content, and between knowing that subject matter and teaching it. Research designs founded on such a theoretical framework may contribute significantly to facilitate bottom-up studies of educational quality for the benefit of academic staff as well as for administrators and quality agencies. It can throw light on the development of written curricula and standards as well as on day-to-day teaching in our institutions.