The problem addressed in this study was that there is a lower amount of young underrepresented minorities (URMs)--African American/Black and Latino/Hispanic students--proficient in science, technology, engineering and mathematics (STEM) who are prepared to enter STEM professions compared to their Asian and Caucasian/White (non-URMs) peers; specifically minority's high school youth who are largely in low-socioeconomic-status (SES) groups of which lack student proficiency and self-efficacy in STEM advanced academic placement (AAP) courses. A stratified, random sampling of data were used. The causal-comparative quasi-experimental design method used a secondary analysis of the outcome variables collected by the Department of Education's survey tool, education data analysis tool (EDAT), during a national longitudinal study utilizing a multivariate analysis of variance (MANOVA). The research question addressed the difference in self-efficacy and STEM education outcomes between URMs and non-URMs. Three themes emerged: college readiness, self-efficacy, and resource scarcity. A significant finding was one's science self-efficacy is linked to STEM outcomes as an identified gap in academic performance. Research findings can guide future policies for STEM reaching youth by pivoting on demographic and self-efficacy variables. The study found that a students' success in STEM AAP courses was linked to self-efficacy level, specifically for URMs who came from majority low-SES areas. The statistical results of the multivariate regression analyses and findings provide a viable solution for targeting a pipeline of diverse talent through STEM education for the next generation workforce. Recommendations include practical application for STEM program assessment, and further research studies for shaping policy for STEM education and outreach initiatives that pipeline the next generation national security defense workforce in government, industry and academia. [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.]