The National Board for Professional Teaching Standards (NBPTS) welcomes the efforts of federal, state, and local policymakers to find new ways to ensure an accomplished teacher for every student in America. The National Board has advanced this mission since its inception in 1987. Today, that mission is carried out by the tens of thousands of National Board Certified Teachers (NBCTs) nationwide--each of whom completed the National Board's rigorous assessment process to demonstrate his or her competence in their teaching field. To further everyone's understanding of how teachers are assessed in a new era of school improvement, NBPTS extended an invitation to several leaders in education evaluation, research, and policy. NBPTS asked them to participate in a series of conversations, share their collective knowledge, and then recommend how the National Board can strengthen its own work in this area while also continuing to be a leading source of information for the field. The result of this important and thoughtful work is summarized in this white paper. This paper also includes several compelling recommendations that the National Board will consider in its future work. [For "Student Learning, Student Achievement: How Do Teachers Measure up?", see ED517574.]