9725512 Doerr Calls for reform in mathematics teaching suggest that teacher should reflect on their own practice and guide their students' mathematical development by creating lessons sequences that support students' efforts to construct increasingly sophisticated understandings over time. However, pre-service teachers in methods courses do not have a practice on which to reflect, and have little, if any, first-hand experience observing the processes by which students develop mathematical conceptions over time. As a result, this proposal has been written to fill this void by creating, implementing, and researching three CD-ROM based case studies centered on actual lessons sequences taught in reform-based classrooms at the middle and secondary level. The two goals of this proposed project are (1) to better understand how multimedia case studies can be used to support the development of effective practice among pre-service mathematics teachers, and (2) to refine our design theory to elaborate specific aspects that make cases more effective in promoting such reflection. ***
