In this exploratory research project, our team's goal was to design and begin validation of a measurement approach that could provide indication of a student's ability to transfer their mathematics understanding to future, more advanced mathematical topics. Assessing transfer of learning in mathematics and other topics is an enduring challenge. We sought to invent and validate an approach to transfer that would be relevant to improving Cignition's product, would leverage Cignition's use of online 1:1 tutoring, and would pioneer an approach that would contribute more broadly to assessment research. [This report was co-produced by MenloEDU with additional funding from Schmidt Futures under a subcontract from Cignition.]