This article presents two antagonistic approaches to the study of educational processes in school teaching. One of them is what is known as the IVŠV video study of teaching as a n instance of quantitative video-studies (KVS); this is an approach that uses deductive category systems to identify the content and form of teaching and learning, and also to produce quantifying generalisation applied e.g. to interactive models in teaching or the subject and subject-didactic specifics of teaching. The second is the content-orientated approach (OZP) to investigating and improving teaching; this is an approach based on an inductive technique in the identification of the content cores of teaching and in qualitative assessment of the didactic quality of teaching situations. These research approaches are then used to explain differences in the character of the didactic knowledge generated by techniques grounded in so-called pre-structured reflection, as compared with didactic understanding (knowledge), generated by so-called post-structured reflection on teaching.