The Advanced Placement (AP) program offers a platform to enact wide-scale reform in our nation's science classrooms, including populations traditionally underserved in science. Research shows that students who pass AP exams are more likely to succeed in college science courses and pursue a career in science. While the number of students participating in this program is growing, the success rate remains relatively low, especially for AP Environmental Science (APES). A critical question for AP educators, and all teachers, is: what can we learn from student responses that can be used to improve instruction, learning, and success in this discipline, for all students? The data for this study consisted of item-level responses from 20,000 randomly selected students who took the 2008 APES exam. Each question was coded to a content area attribute defined by the College Board (e.g., population, land/water use), a crosscutting science concept defined by the Next Generation Science Standards (e.g., patterns, cause/effect), and a level of Bloom's Taxonomy (remember, understand, apply). Results from a cluster analysis on responses from students who passed with a score of a 3, and students who failed with a score of a 2, were matched to socio-economic and demographic data. Further significance testing was also conducted on these findings. The results identified distinct response patterns among groups of passing and failing students. While students achieved the same final score, they did so by excelling in different questions representing various reasoning and skill levels. Some students passed with a low score on quantitative and higher-reasoning questions coded as Bloom's level of "apply." Furthermore, there were significant differences among gender and student achievement on the APES exam overall, and in this attribute domain of apply. The methods utilized identified domains where students needed support, which can be used by many stakeholders to improve success rates on this and similar exams. Teaching higher-level reasoning skills and addressing the gender gap may lead to greater success on this exam. Recommendations for curriculum, teaching, and policy, supported by these findings, are discussed in hopes to increase success in this course for students of all backgrounds and gender. [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.]