In this report, the authors look at the freshman year course performance of Chicago Public Schools (CPS) students who receive special education services and ask whether grades, course failures, absences, and on-track status are useful for identifying students who are at risk of dropping out. They also examine how academic behaviors, such as attendance and study habits, affect course failures and grades of students with disabilities. Consistent with the original "What Matters" report, most of the analyses in this report are based on information about the cohort of CPS students who were first-time freshmen in 2004. When reporting graduation rates, the authors use information about the cohort of CPS students who were first-time freshmen in 2001. They report four major findings: (1) Students with speech/language disabilities and students with physical/sensory disabilities perform similarly to students without identified disabilities in their freshman year courses. Students with emotional disturbances and students who entered high school two or more years below grade level had the lowest level of course performance of any group they studied; (2) Freshman year course performance is a strong predictor of five-year graduation rates for students with disabilities and students who entered high school two or more years below grade level; (3) Higher absence rates are an important factor explaining why students with disabilities fail more classes and have lower grades than students without identified disabilities; and (4) Students with learning disabilities and students with mild cognitive disabilities do not benefit as much from rigorous study habits as students without identified disabilities. Appended are: (1) Study Samples; (2) Special Education Categories; (3) Statistical Models; and (4) Sample Attrition in Statistical Models. (Contains 6 tables, 20 figures, and 33 endnotes.)