Lesson Study: the Effect on Teachers’ Professional Development

This study combines elements of the Japanese Lesson Study approach and teachers’ professional development. An explorative research design is conducted with three upper level high school teachers in the light of educational design research, whereby design activities will be cyclically evaluated. The Lesson Study team observed and evaluated two different research lesson cycles. The first one focused on the concept of the derivative. The second one deepened teachers’ pilot experiences with regard to another mathematical concept. The Lesson Study revealed students’ misconceptions with regard to the tangent line. Results of teachers’ professional development are used to refine the Lesson Study observation instruments.