The 2020 election brought about legislative change across the country. New and veteran policymakers need information about the schools in their state. What programs are the most cost effective and work best for students? How can states attract and retain great teachers? What information do parents need to ensure that their kids are on track to graduate? High-quality data is a critical tool to answer questions like these and help inform policy decisions. Likewise, everyone involved in a child's education needs timely, accurate data to provide insights and drive improvements for students. Data is a critical part of education policy conversations in every state--and this briefing book is meant to bring policymakers up to speed on 10 of the most pressing topics, with the following information: (1) a basic overview of the topic; (2) why it matters; (3) the "state of play" on the latest progress in that area; (4) recommendations to take action; and (5) additional resources to help build an understanding of data topics and policies. [For the 2017 edition of the Briefing Book, see ED586473.]