“…Based on these activities teachers identify a key concept that underlies a number of learner errors. They then read and discuss research on learners' thinking in those concepts (Molefe, Brodie, Sapire, & Shalem 2010), design lessons to engage with learners' thinking, and then videotape and reflect on those lessons (Brodie, 2011;Brodie & Shalem 2011). In the current phase of the project, DIPIP Phase 3 (2011-2012), we are working in schools with mathematics departments, using the activities to build the departments' collective engagement with data from their schools, and their design of and reflection on lessons based on their data analysis.…”