To diagnose skills in learners, teachers must themselves have diagnostic skills. The scientific discussion of this teacher-competence has been subject of a more intensive examination, since a PISA study attested German teachers poor diagnostic results. In addition, the assignment to further personal development (individually) also contributes to analyzing the field of educational diagnostics. This paper reconstructs a model of diagnostic teacher competence, which takes into account both competence dimensions, the diagnostics of coming to a judgment and process diagnostics. The model serves as a normative benchmark for comparing the everyday diagnostic paradigms of the investigated teachers. Aside from containing the portfolio of diagnostic knowledge, an everyday paradigm also comprises subjective theories, orientations or the know-how of routine actions and affects diagnostic skills. This research will examine how the diagnostic everyday paradigm can be changed by participating in a training program and which link exists between the dynamics of development and the frames of orientation of the teachers. It turns out that certain teacher-orientations support the development of diagnostic competence, whereas others inhibit a change. The results of this investigation will be correlated with the principles for designing teacher-training courses and teaching programs. As well as furthering personal development (individually) in learners, the stage and the history of learning of the teachers have to be assessed with diagnostic instruments in a structurally similar way and have to be considered for future professional training. Moreover, it becomes obvious that the factors time, reflection, team and theory in the work of teacher-teams have to be reevaluated.