The present study is part of the research project “Didaktische Interventionsformen für
einen selbständigkeitsorientierten aufgabengesteuerten Unterricht am Beispiel Mathematik”,
in English “Didactical intervention modes for mathematics teaching oriented towards
self-regulation and directed by tasks” (DISUM). This is an interdisciplinary project
between mathematics education (W. Blum), pedagogy (R. Messner, both University of
Kassel) and educational psychology (R. Pekrun, University of München) which started in
2002. It aims at investigating how students and teachers deal with cognitively demanding
modelling tasks, in particular what kinds of teachers’ diagnoses and interventions are
appropriate for supporting students solving such tasks independently, and what effects
different learning environments for modelling have on the development of students’
competencies and affect. The focus is on grades 8–10 (14–16 years old).