Design and development are critically important to the educational enterprise. Unfortunately, there is little research on which design and development processes produce optimal outcomes for curricular materials intended for large-scale implementation. The Design Dimensions project asks: Across phases of design (analysis, development, and evaluation), what processes and strategies are critical to successfully obtain large scale implementation with significant impacts on learners? Our work examines design processes with respect to three themes in science education: Deep Understanding and Rich Performance; Social and Cultural Experiences; and Implementation in Diverse and Resource-Limited Settings. A series of ‘deep dive’ studies examines designer processes in two successful contexts: the Lawrence Hall of Science and TERC. The first phase of investigation includes four retrospective case studies. This poster presents the theoretical framework and methodological approach used to investigate the work of successful design teams. We seek feedback from designers at ISDDE about the approach taken thus far.