Advanced Placement courses and exams are seen as marks of distinction for high school students, but it remains unclear how participation in AP affects student performance at the post-secondary level -- a problematic situation given that "open enrollment" policies have vastly increased the numbers of students participating in AP. Data were collected (N=93) to compare post-secondary history-course grades and overall GPA among students who 1) completed an AP history course and earned college credit on the exam, 2) completed the course but failed to earn credit on the exam, or 3) did not participate in the course or exam. Students who earned credit on the exam outperformed students who did not participate in AP, but students who failed to earn credit on the exam performed similarly as those who did not participate in AP, whereas test-takers who received credit did not differ from ones who did not. Similarly, students who earned college credit on the AP exam did not differ from those who failed to earn credit. In overall college GPA, the groups did not differ, although AP exam scores were significantly and positively associated with college GPA. Among students who took the exam, it was found that those who had higher scores on the AP exam would have been expected to have a significantly higher score in their post-secondary course. Results as such are mixed for open-enrollment policies, suggesting that the benefits of AP for college students were evident largely among students who performed well on the exam, and likely exclude students who failed to earn college credit (and in years past may have opted not to participate in AP). [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]