In February 1988 the Board of Education of the San Diego City Schools (California) adopted a core curriculum for all district schools. The implementation of this policy was studied in 1990 and 1992, and again in this followup study. Part I of this report provides an analysis of student enrollment and achievement data from 24 selected sites and followup data on a separate longitudinal analysis of the course enrollment and academic progress of a cohort of 6,700 students (enrolled in the regular mathematics or advanced mathematics courses in 1988-89) graduating in spring 1994. Part II provides an analysis of interview and survey data from 377 students, 2,402 parents, and 540 teachers. The longitudinal study data focusing on mathematics achievement show that, for most students, course enrollment at grade 7 is somewhat predictive of mathematics enrollment and achievement patterns throughout high school. More students enrolled in the regular math course dropped out, earned lower grades, or fell short of graduation requirements. Enrollment and achievement data suggest that the core curriculum policy has not eradicated academic stratification in that African American and Hispanic students continue to be over-represented in courses intended for earlier grade levels. Overall study data suggest that programming students into core courses that are appropriate to their levels of preparation, motivation, and achievement is difficult to implement. Nevertheless, implementation of the policy, by most accounts, has ensured access to a common core curriculum and eliminated a number of previously identified barriers to disadvantaged students. (Contains 32 tables, 41 figures, and 17 references.) (SLD)