Over the past two decades, college and career readiness became a priority in K-12 education. While graduation rates have been rising, far too many high school graduates are not ready to succeed in college or a job. Employers note that freshly-minted employees too often need additional training to perform their roles, many are ineligible for military service because they fail to get adequate scores on the entrance exam, and first-year college students across the country must pay to take no-credit remedial classes on content they should have learned in high school.1 The U.S. economy depends on these graduates, so it is urgent that state boards of education figure out why so many students remain unprepared. Many states are ill equipped to do so. There is an astonishing lack of publicly reported data on student performance in grades K-12, and the information that is reported varies widely across states. The fact is that state policymakers cannot make good education policy and practice decisions--and ultimately cannot improve student performance--without basic information about how students are performing along the way. To fix this problem, state boards and state education agencies (SEAs) must know their starting point and be able to measure progress and change over time.