In 2005, the U.S. Department of Education's Office of Elementary and Secondary Education issued a request for proposals (RFP) for programs to improve adolescent literacy. The Department's stated goal was to improve the performance of struggling adolescent readers and help build a strong scientific research base around specific strategies to help struggling readers. In response to the RFP, the Chicago Public Schools (CPS) proposed the Chicago Striving Readers (SR) program. This five-year program aims to transform teaching and learning through a seamless, aligned approach to literacy instruction for grades 6-8 across 31 schools. The Chicago Striving Readers program uses a tiered approach to working with adolescent readers. At the start of the school year, students are classified into three groups: those meeting or exceeding state performance standards for their grade (Tier 1), struggling readers who could reach grade level with focused support in the classroom (Tier 2); and struggling readers who require long-term intensive support and customized instruction (Tier 3). All three tiers receive the benefits of a whole-school ("blended"4) intervention. Tiers 2 and 3 benefit from both whole-school and targeted interventions, and Tier 3 students benefit from the whole-school, targeted, and intensive interventions. This report describes the evaluation of the fourth year of implementation of the five-year Chicago Striving Readers program. The fourth year evaluation involved 29 treatment schools (16 from Cohort 1 and 13 from Cohort 2) and 30 control schools (15 per cohort).