As the national education policy community prepares for the reauthorization of the No Child Left Behind Act of 2001 (NCLB), revamping the school improvement approach leveraged by accountability systems has risen to the top of the agenda. There is an emerging consensus that the school improvement process should be systemic, led by states and districts, based on detailed information about student and school performance, and tailored to meet the individual needs of students and schools. There is also recognition that success is dependent on increased capacity--including skill, knowledge, people, and resources--at the state and district levels to support, manage, and, where necessary, direct these efforts. In this context, the goal of federal policy should be to leverage and support a systemic approach for addressing the problems in the nation's lowest-performing high schools--at scale. This brief examines the current federal approach to addressing the lowest-performing high schools, explores lessons learned from emerging strategies at the state and local levels, and provides related recommendations for federal policy. (Contains 3 footnotes and 70 endnotes.)