Classroom observation has changed dramatically in recent years. Trivial checklists have given way to research-based rubrics that describe important aspects of teaching and, for each aspect, explain the difference between more and less effective practice. Instead of asking if the lesson objective was posted, these new instruments typically ask to what extent the objective was clear to students, how well the teacher connected the objective to students’ prior knowledge, and to what extent the teacher reinforced the objective throughout the lesson. This clarity around what to look for in a lesson has tremendous potential. It makes it possible for different observers to reach the same conclusions about how well a lesson demonstrates a set of practices that matter to student learning. This is essential for