As part of its College Readiness System, ACT offers the PLAN[R] program as a way for tenth-grade students to review their progress toward college readiness while there is still time to make necessary interventions. PLAN contains four tests--English, Mathematics, Reading, and Science. These tests are designed to measure students' curriculum-related knowledge and the complex cognitive skills important for future education and careers. Scores range from 1 to 32. ACT examined the relationships between students' scores on PLAN and their scores on selected AP Exams. In this study, ACT developed new score linkages for AP courses that align in curricular content with the four PLAN tests and updated the linkages found in earlier studies. Results from this study show that PLAN test scores are good predictors of success in AP courses, as defined by receiving a score of 3 or higher (or 4 or higher) on the appropriate AP Exam. The PLAN/AP linkages identified in this study can be used by schools and educators to (1) provide inquiring students and their parents with information regarding their likelihood of success on an AP Exam; (2) identify students who should take additional preparatory coursework prior to taking an AP course; and (3) determine the number of students who might be eligible for an upcoming AP course. (Contains 1 table.)