Part of the Math Assessment Project has involved research into how the materials are used in classrooms, their effect on teaching practices, and how Professional Development can be used to support the goals of the Mathematics Assessment Project materials. A major strand of this has been a joint effort with the Algebra Teaching Study at UC Berkeley and Michigan State to develop the Teaching for Robust Understanding of Mathematics (TRU Math) suite of tools for Professional Development and research. During development of TRU Math, it became clear that the concepts could be generalized into a