Since President Obama took office, Congress has appropriated more than $4 billion to help turn around the nation's lowest-performing schools. States were awarded nearly $3.5 billion in School Improvement Grant funds in 2010 to turn around their persistently lowest achieving schools. School districts then applied to state for the funds this spring. When school districts applied, they were required to indicate that they would implement one of the following four models in their persistently lowest achieving schools: Turnaround Model: Replace the principal, screen existing school staff, and rehire no more than half the teachers; adopt a new governance structure; and improve the school through curriculum reform, professional development, extending learning time, and other strategies. Restart Model: Convert a school or close it and re-open it as a charter school or under an education management organization. School Closure: Close the school and send the students to higher-achieving schools in the district. Transformation Model: Replace the principal and improve the school through comprehensive curriculum reform, professional development, extending learning time, and other strategies.