Education needs generalizable models to scale up evidence-based practices and programs and longitudinal research evaluating the persistence of the effect of their implementation. This is particularly important given the "deep, systemic incapacity of U.S. schools, and the practitioners who work in them, to develop, incorporate, and extend new…

Although basing instruction on a learning trajectory (LT) is often recommended, there is little direct evidence to support the premise of a "LT approach"--that to be maximally meaningful, engaging, and effective, instruction is best presented one LT level beyond a child's present level of thinking. The present report serves to address…