States and districts have launched unprecedented efforts in recent years to build new feedback and evaluation systems that support teacher growth and development. These systems depend on trustworthy information about teaching effectiveness--information that recognizes the complexity of teaching and is trusted by both teachers and administrators.…

Research has long been clear that teachers matter more to student learning than any other in-school factor. Improving the quality of teaching is critical to student success. Yet only recently have many states and districts begun to take seriously the importance of evaluating teacher performance and providing teachers with the feedback they need to…