With our interest to improve our education in computer science, an understanding of how students learn about CS concepts, how different concepts are understood, as well as the conditions for learning, become important issues. A better understanding of our students and their learning gives us a strong tool in our efforts to develop teaching. There is an increasing awareness of the usefulness of theoretically sound research approaches: it opens for generalisations of results, it invites comparison between researchers, methods and results, and at the same time it makes the limits of the research visible. As examples on initiatives that have lately been taken to promote a conscious use of relevant research approaches, can be mentioned the bootstrapping project [13], the special issue on import and export of Computer Science Education (to appear), as well as papers offering overviews of the current use of certain approaches ([4], [8]) and attempts to verbalize models for a successful resea...