Given that there is no universal way to measure implementation fidelity, instructional designers developing instructional innovations may find themselves faced with the challenge of determining the extent to which teachers' implementation of an instructional model is faithful. This article contends that a faithful implementation is one in…

In many ways, algebra can be as challenging for teachers as it is for students. With so much emphasis placed on procedural knowledge and the manipulations of variables and symbols, it can be easy to lose sight of the key ideas that underlie algebraic thinking and the relevance algebra has to the real world. In the The Xs and Whys of Algebra: Key…