The "Elementary and Secondary Education Act of 1965" ("ESEA") is the nation's key policy driver for elementary and secondary education, shaping federal, state and district efforts to promote effective school systems and improve educational outcomes, particularly for students in high-poverty schools. The most recent reauthorization of "ESEA" (the "No Child Left Behind Act of 2001," or "NCLB") called for landmark changes. This report explores the early implementation of state-differentiated recognition, accountability and support systems under the U.S. Department of Education's "ESEA" flexibility initiative, announced in September 2011. "ESEA" flexibility offers states flexibility with regard to how states set annual measurable objectives (AMOs), whether or not they continue to calculate adequate yearly progress (AYP), designate low-performing schools and districts, implement interventions, use section 1003(a) funds, determine transferability of "ESEA" funds and implement improvement plans for highly qualified teachers. The findings are based on telephone interviews conducted with a sample of state, district and school-level officials in late 2013 and early 2014, and a review of relevant policy documents that were available on state and local education agency websites during this same time period. Participants in the state and district sample included officials from 12 state education agencies with approved "ESEA" flexibility requests and 22 districts located within these 12 states. The school-level sample drew from the state and district sample and participants included principals of 25 Title I schools located within a subset of 12 districts and six states. Although the state, district and school samples were diverse, the states, districts and schools were not randomly selected and are not representative of the larger population of 35 states whose "ESEA" flexibility requests had been approved at the time of this study and the districts and schools within these states. Thus, the findings presented in this report are not generalizable. The purpose of this study was to explore state and district processes, successes and challenges, as well as school-level experiences associated with the early implementation of the accountability provisions of "ESEA" flexibility. [For the results in brief, see ED613361.]