The Title I program, created in 1965, is the largest federal program supporting elementary and secondary education and is intended to help ensure that all children have the opportunity to obtain a high-quality education and reach proficiency on challenging state standards and assessments. The No Child Left Behind Act of 2001 (NCLB) expanded the assessment and accountability provisions in the law while also creating new provisions related to parental choice and teacher quality. The purpose of this report is to examine the implementation of key Title I provisions related to state assessments, accountability, school choice and supplemental educational services, and teacher quality, as well as examining trends in student achievement. The report synthesizes key findings from a variety of studies and data sources, including the National Longitudinal Study of No Child Left Behind and the Study of State Implementation of Accountability and Teacher Quality Under No Child Left Behind which are repeated cross-sectional surveys of states, districts, and schools, as well as state performance reports and the National Assessment of Educational Progress. The following are appended: (1) Descriptions of Major Data Sources Included in This Report; (2) Supplemental Exhibits; and (3) Standard Error Tables. (Contains 91 exhibits and 185 endnotes.).