Part of the third-largest school district in the nation, 77 percent of Chicago's nearly 427,000 public school students are poor, as defined by eligibility for participation in free or reduced-cost lunch programs. Many are members of minorities; many have limited proficiency in English. To make a successful transition to college--even to graduate from high school--many young people in the Chicago school system face hurdles unimaginable in the nearby suburbs. The Chicago Public School system (CPS) wants to increase the college readiness of the city's students. Its goal is to increase the numbers of students who take a rigorous curriculum and set their sights on getting into the most challenging college for which they are qualified. The CPS also wants to improve high school graduation rates and college attendance rates, and to provide a basis for curricular interventions to improve student performance. This paper describes how CPS was able to monitor the effectiveness of its curriculum and improve its college readiness through the implementation of EXPLORE[R], PLAN[R], and the ACT programs.