The authors of a recently released Thomas B. Fordham Institute study found that large numbers of elementary, middle grades, and secondary teachers were not assigning reading texts to students with the appropriate grade level complexity. In their preliminary exploration of the implementation of the Common Core State Standards (CCSS) for English/Language Arts, the researchers surveyed 484 high school teachers with questions designed to provide insight into teachers' adoption of the CCSS requirement for practice for grade appropriate texts, regardless of the independent or instructional reading level of the student (Shanahan & Duffett, 2013, p.16). After analyzing the survey response data, the authors found that many teachers have not yet confronted the new text complexity demands of the Common Core ... [E]ven in high school relatively large proportions of students were assigned texts based mainly on their current reading levels (p. 22). In other words, teachers are still assigning texts that correspond to a student's present ability rather than choosing texts that are beyond that student's comfort level but which meet CCSS criteria. The Fordham study makes clear that in order to be in compliance with the new set of standards, teachers in the English/Language Arts classroom must rethink the decisions they make in choices of classroom texts. In addressing this issue, the authors made a distinction with respect to the term differentiation. They wrote, American schools have long attempted to differentiate instruction to meet individual students' learning (p. 15). With the adoption of the CCSS by 46 states, the process of has been reinterpreted. The authors continued: But the Common Core discourages teachers from doing this out-of-level teaching. Instead, the standards demand regular practice with grade-appropriate texts, regardless of the independent or instructional reading level of the student. The idea is that teacher support and explanation, not text difficulty, is what should be differentiated to meet the needs of struggling readers. (p.16) The distinction the authors make is important and does not solely concern current literacy discussions. More generally, it has implications for the practice of all teachers accustomed to differentiating instruction based on an alternate understanding of the term. Instead of differentiating curricular materials (i.e., texts), teachers are now tasked with presenting a standard, grade appropriate curriculum and then differentiating instructional practice in order to accommodate the varying abilities of a classroom full of diverse learners. The nuances represented here with respect to a term like differentiation are difficult for teachers to interpret and implement in their daily practice, particularly given the lack of available resources for professional development and the increasingly rapid pace of educational policy changes. Further, teachers are tasked with implementing these new policies and standards without models that have been field-tested or subjected to the rigorous analysis of program procedures that would potentially reveal difficulties prior to wider implementation. This analysis, in fact, is what the Fordham study is attempting to do, and it is necessary work. But, unlike pilot programs, the results of large-scale policy innovations are situated in real time, affect an enormous number of real people, and have real world, rather than laboratory, consequences. As a secondary teacher and an educational researcher, I am daily confronted with the challenge of reconciling classroom practice, current research in the field, and educational policy. …