After carefully vetting and selecting a new curriculum, a school district rolls it out enthusiastically, hoping it will improve students’ math scores. District leaders dedicate time and effort to the professional learning to support the program. Yet despite planning for these changes and investing in teachers’ knowledge of the curriculum, what happens in each classroom varies widely. Some teachers skip the professional learning sessions and never look at the materials. Some incorporate a few of the curriculum components but struggle with the pacing, so they don’t get through the lessons fully. Others diligently attempt to keep up with the pacing guide, but without pausing to thoroughly reflect on how it’s going, there’s no way to know if students are mastering the content. “No one would