CIES 2018 Presentation, given by Ben Piper. The Tusome national literacy program has been implemented in each of Kenya’s more than 22,000 public primary schools and 1500 low cost private schools in the slums since 2015. In addition to showing the comparisons between before and after Tusome’s implementation, this presentation will examine Tusome implementation data to reveal key characteristics of the scale-up framework that Tusome was designed to respond to. In particular, we share the extent of classroom utilization of the Tusome materials, the size of the classroom observational structures that Tusome tried to revitalize, and the responses of the community to the Tusome intervention. The findings suggest that Tusome had a substantial impact on literacy outcomes in both Kiswahili and English, in both Grade 1 and 2, in both public and low cost private settings, and in both urban and rural settings. This means that the program’s effect meant that nearly 1 million more children were able to be considered readers by the midterm intervention.