CPRE released its evaluation of one of the most ambitious and well-documented expansions of a U.S. instructional curriculum. The rigorous independent evaluation of the Investing in Innovation (i3) scale-up of Reading Recovery, a literacy intervention for struggling first graders, was a collaboration between CPRE and the Center for Research on Education and Social Policy (CRESP) at the University of Delaware. The CPRE/CRESP evaluation revealed that students who participated in Reading Recovery significantly outperformed students in the control group on measures of overall reading, reading comprehension, and decoding. These effects were similarly large for English language learners and students attending rural schools, which were the student subgroups of priority interest for the i3 scale-up grant program. The study included an in-depth analysis of program implementation. Key findings focus on the contextual factors of the school and teachers that support the program’s success and the components of instructional strength in Reading Recovery.