Science, Technology, Engineering and Mathematics (STEM) outreach programs are one of the many tools currently utilized to grow the appreciation of STEM in young minds. The hope behind these outreach efforts is to ensure a future workforce of Scientist and Engineers. A great bolstering of the ranks is needed due to the continuous decline in the number of students choosing to take on these important disciplines. This work lays out a series of research efforts which apply Systems Engineering tools and philosophies to enhance and optimize the STEM outreach system for K-12 students. Based on these investigations and their findings, a deeper understating of how students' progress along the STEM career pipeline is achieved. Further, findings are presented in this work which are based on efforts to use existing Science and Engineering professionals' reflections on past career choices to gain this insight. From these reflections an increased understanding of students mindsets shifts towards STEM is presented. Findings include patterns of career selection, including evidence of rapid career adoption at lower grades. From this work the development of the STEM career pipeline system is established and recommendations are provided to aid organizations in providing STEM outreach, thus optimizing the overall STEM Outreach eco-systems and the STEM career pipeline. [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.]