Too many of our nation's youth have failed to complete high school. Determining why so many of our nation's students fail to graduate is a complex, multi-faceted problem and beyond the scope of any one study. The study presented herein utilized a thirteen-step mixed methods model developed by Leech and Onwuegbuzie (2007) to demonstrate within a large urban Rocky Mountain school district, the existence of a significant relationship between high school algebra performance and high school completion and to provide one suggested framework by which to explain the nature of this relationship. Quantitative analysis showed that a failing grade in a student's first high school algebra course is not only a significant predictor of failure to graduate high school but was more liable, than several other predictors, to forecast which students are more likely to leave high school before earning a diploma within four years. However, quantitative examination revealed only the existence of a significant relationship between these two variables. It fell short of providing any elucidation as to why performance in high school algebra can be considered as a predictor of failure to graduate high school. Qualitative analysis, using the tradition of phenomenology (Moustaskas, 1994), was employed to expand on the quantitative analysis and offer a hypothesis from a student-centered perspective as to why this relationship may exist. Several students, who have returned to school after dropping out or who have been in high school for more than four years, were interviewed about their individual experiences in high school algebra classes and the greater high school environment. The qualitative analysis results did not conclusively agree with the quantitative results, and failed to conclusively point to high school algebra as the overwhelming reason for high school dropout. Nonetheless the interviews revealed that the students perceived numerous negative sources of self-efficacy and expectancies that, when combined with the uniqueness of the high school algebra experience, increased the likelihood of failing to graduate high school. [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.]