This study explores the differences in student achievement on state standardized tests between experiential learning and direct learning instructional methodologies. Specifically, the study compares student performances in Expeditionary Learning schools, which is a Comprehensive School Reform model that utilizes experiential learning, to their counterparts or peer schools that utilize traditional instructional methodology. This study employs a quasi-experimental quantitative design. Student test scores and individual answer responses on the New York State Regents Living Environment, Earth Science and Chemistry science exams from the June 2012 and June 2013 administration were analyzed for both the Experiential Learning and the Traditional Learning groups. Descriptive as well as inferential statistical analyses were performed on the data to determine the differences in students' mean scores on various attributes of the test, as well as differences in achievement levels for various sub-groups of the sample. The study found that the Experiential Learning group had statistically significant greater mean scores in overall performance on Living Environment, Earth Science and Chemistry exams than the Traditional Learning group. The study also found that students in the Experiential Learning group outperformed their peers on critical thinking questions on all [three] science exams combined, as well as on the Earth Science laboratory practicum exam. Additionally, the study found that English Language Learners (ELL's) and students with an Individual Education Plan (IEP) in the Experiential Learning group significantly outperformed their counterparts in the Traditional Learning group. This study concludes that Experiential Learning should be leveraged as a comprehensive school reform model to increase students' overall performance on state standardized science examinations. This study also concludes that Experiential Learning should be capitalized upon to increase student development of critical thinking skills, as well as for students with special academic needs. Finally, this study provides further evidence that district and school leaders should strongly consider Experiential Learning, as a comprehensive school reform model, a viable option to enable student achievement. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]