In 2001, Illinois began administering the ACT (American College Testing) test to all 11th graders in Illinois public schools as part of the Prairie State Achievement Exam (PSAE). For the first time, ACT scores and background information were available for most public-school students who would be completing high school one year later, rather than just those who elected to take the test because they were expecting to apply to a postsecondary institution that asked for ACT scores. The authors refer to this cohort of public high school graduates as the Illinois Class of 2002. In this study, they use a unique dataset combining student ACT scores and background information with postsecondary enrollment and completion information from the National Student Clearinghouse (NSC), Illinois Community College Board (ICCB), and the Illinois Shared Enrollment and Graduation (ISEG) to track the Illinois Class of 2002 on their journeys into higher education throughout the country. The goal of this longitudinal project is to understand students' transitions from high school to college and their persistence and attainment over time. They plan to follow the cohort for six years, through the 2007-08 academic year. Overall, findings reveal that students with higher income parents were more likely to complete baccalaureate degrees, while students with lower income parents were more likely to earn certificates or associate degrees. (Contains 16 figures and 1 table.)