Teach For America (TFA) is a nonprofit organization that seeks to improve educational opportunities for disadvantaged students by recruiting and training teachers to work in low income schools, and then encouraging these teachers to assume leadership positions from which they can continue to work to reduce educational inequity. The program uses a rigorous screening process to select college graduates and professionals with strong academic backgrounds and leadership experience and asks them to commit to teach for two years in high-needs schools. These teachers, called corps members, typically have no formal training in education but participate in an intensive five-week training from TFA before beginning their first teaching job. TFA then provides them with ongoing training and support throughout their two-year commitment. TFA encourages teachers who complete their two-year commitment, known as TFA alumni, to continue working to improve educational opportunities for disadvantaged students, whether by remaining in the classroom or by assuming roles of educational leadership and advocacy. TFA was founded in 1989 and placed its first cohort of 384 corps members in classrooms in the 1990–1991 school year. Since that time, the program has launched several major expansion efforts, and in the 2010–2011 school year, TFA had approximately 8,200 first- and second-year corps members teaching in 40 urban and rural regions across the country.1 In 2010, TFA launched another major expansion effort, funded in part by a five-year Investing in Innovation (i3) Scale-Up grant of $50 million from the U.S. Department of Education’s Office of Innovation and Improvement.2 This was one of four i3 scale-up grants awarded in 2010. These scale-up grants were intended to fund expansion of programs with rigorous evidence of prior effectiveness in improving student achievement. Through the i3 scaleup project, TFA planned to increase the size of its teacher corps by more than 80 percent by September 2014, with the goal of placing 13,500 first- and second-year corps members in classrooms by the 2014–2015 school year, and expanding from 40 to between 52 and 54 regions across the country, and accounting for approximately 20 percent of new hires in high-poverty schools in these regions (Teach For America 2010). TFA has contracted with Mathematica Policy Research to conduct a rigorous, independent evaluation of the i3 scale-up project’s effectiveness, a requirement for all i3 scale-up grantees. This evaluation includes an analysis of the scale-up’s implementation as well as an analysis of the impact of elementary school TFA teachers recruited and selected in the first and second years of the scale-up. This report presents findings from the implementation analysis; the impact findings are presented in a separate report (Clark et al. 2015). This implementation analysis examines the implementation of the i3 grant during the first and second years of the scale-up. TFA initiated the scale-up in 2010 and began to conduct program activities under the i3 grant, including the recruitment, selection, and placement of future cohorts of corps members. Because TFA recruits and selects corps members in the spring before its teachers begin teaching, the first cohort of teachers selected and recruited under the grant began teaching in the 2011–2012 school year, and the second cohort began teaching in the 2012–2013 school year. The implementation analysis examines key features of the scale-up for these first two scale-up cohorts.