Teacher Knowledge Experiment (T-Knox): The conditions of the development of subject related didactical knowledge


Supported by DFG in the research priority program "Kompetenzmodelle" (KL 2355/1-1)

Term: April 2012 – March 2014

Starting positions and objectives

The professional knowledge of teachers is usually subdivided into subject related, pedagogical and subject related didactical knowledge. Subject related didactical knowledge comprises the knowledge that teachers need to efficiently teach subject related to content. The importance of this knowledge for the instructional quality and the learning success of students has been proven empirically at several instances. However, the findings concerning the question how prospective teachers develop subject related didactical knowledge are rare. In an experimental study, we investigated the importance of accessible subject related knowledge and accessible pedagogical knowledge for development of subject related didactical knowledge. Three assumptions were examined: (a) Subject related knowledge and pedagogical knowledge amalgamate to subject related didactical knowledge ("Amalgam-Hypothesis"), (b) subject related didactical knowledge emerges "en passant" from subject related knowledge ("Carry-Hypothesis") and (c) subject related knowledge supports the use of teaching opportunities for subject related didactical knowedlge ("Moderator-Hypothesis").


The participating 100 teacher training students from Berlin and Brandenburg were randomly assigned to one of five courses. The courses comprised two 4 hour-block sessions. The "Amalgam-Condition" comprised one block on subject related knowledge and one block on pedagogical knowledge, the "Carry-Condition" comprised two blocks on subject related knowledge and the "Moderator-Condition" comprised one block on subjectz related knowledge and one block on subject related didactical knowledge. Furthermore a weak control condition comprised exclusively blocks on pedagogical knowledge, while a strong control condition was exclusively confronted with blocks on subject related didactical knowledge.


Zwei Studenten und eine Tasse Kaffee

Overview of the design

The subject related didactical blocks covered the teaching of fractions in 6-year elementary school. The subject related and pedagogical blocks each had special content overlaps with the subject related didactical blocks: the subject related blocks covered fractions without thematising the teaching of these contents in class. The pedagogical blocks generally covered the subjects of teaching and learning, i.e. representational forms, students' conceptions, learning difficulties and teaching strategies without creating a reference to mathematics. Correspondingly, there were no content overlaps between the subject related and the pedagogical blocks. The central dependent variable, the subject related didactical knowledge, was measured before, during and immediately after the first two course blocks as well as six weeks after the course.


Under the weak control condition, the students developped little to none new subject related didactical knowledge. In opposite to this, the students of the "Amalgam-" and "Carry-Conditions developped additional subject related didactical knowledge. However, compared to the strong control group which was explicitly taught subject related knowledge in their course blocks and in comparison to the "moderator-condition", the growths were comparatively low. Moderator effects of the accessible subject related knowledge in terms of an improved use of teaching opportunities for subject related knowledge could not be proven; in the strong control group and in the "Carry-Condition", the participating students acquired subject related didactical knowledge to a similar extent.

Zwei Studenten und eine Tasse Kaffee

Involved persons

Thilo Kleickmann, CAU Kiel, Department of Research on Teaching and Teacher Education

Aiso Heinze, IPN Kiel, Department of Mathematics Education

Mareike Kunter, Goethe-Universität of Frankfurt, Educational Psychology

Andrea Bernholt, IPN Kiel, Department of Educational Science

Steffen Tröbst, CAU Kiel, Department of Research on Teaching and Teacher Education

Roland Rink, TU Braunschweig, Institute for the Education of Mathematics and Elementary Mathematics


Contact information

Dr Steffen Tröbst (troebst@paedagogik.uni-kiel.de)