In 2008, New York City's Center for Economic Opportunity (CEO) launched the Young Adult Literacy (YAL) program to improve the academic and work-readiness skills of youth who are not in school, do not have a job, and have very low literacy skills. The YAL program targets 16- to 24-year-old young adults who read at the fourth-through eighth-grade levels, and serves them until they are academically ready to enter a program that prepares them for a high school equivalency (HSE) certificate. In the summer of 2013, MDRC conducted an implementation study of five YAL sites in order to explore factors that facilitate or challenge successful program implementation. This report presents the findings, which are largely based on an analysis of qualitative data from staff interviews, participant focus groups, and observations of classrooms and internships, as well as a review of program participation data. The following are appended: (1) Glossary of Widely Used Terms and Acronyms; (2) Supplementary Tables on the Common Core State Standards and Balanced Literacy; and (3) Side-by-Side Comparison of Program Implementation at the Study Sites.