Meeting Science, Technology, Engineering, and Mathematics (STEM) workforce demands require students to have positive attitudes and persist through the STEM pipeline. There is limited research on reliable and valid instruments that measures non-cognitive skills towards all STEM fields. Tools that have been developed have mostly used traditional scale development process of literature review on current instruments, expert and target group consultations, and peer review to develop and guide the conceptual domain. While this is a well-established and validated approach, it does not, however, build on the ideas of the various stakeholders (educators, researchers, professionals, students, and parents) that are involved at improving the STEM pipeline. Additionally, existing tools primarily use classical test theory (CTT) and factor analysis methods for validation. A structured methodology of Concept Mapping (Trochim, 1989a) was used in this study to develop the conceptual domain of attitudes and persistence via a participatory framework. This involved the STEM community from engagement to participation in research ranging from consultation, to involvement, and to collaboration, to develop the attitude and persistence towards STEM (APT-STEM) instrument. The instrument was validated across the quantitative psychometric frameworks of CTT, item response theory (IRT), and Rasch measurement theory (RMT). The entire study employed the exploratory quantitative priority sequential mixed methods design. In the first concept mapping phase, a total of 190 different STEM stakeholders built an item pool of 699 attitude ideas and 674 persistence ideas. With the use of nested and parallel sampling of a subset of the initial stakeholder group, these ideas went through a structured and rigorous qualitative and quantitative analysis. The resulting concept maps organized the stakeholder's conceptualization of the attitude and persistence constructs. Using qualitative and psychometric techniques, a total of 30 items were selected and refined to form the APT-STEM instrument. In the second quantitative phase of validation, APT-STEM was administered to 556 grade 5-12 students from different STEM programs who were a representative sample of the student stakeholder group. The data was analyzed using the psychometric frameworks with IRT and RMT contributing to more diagnostic details about the instrument compared to CTT. The instrument thus developed has items that were different from existing instruments. Stakeholder's conceptualized responsibility, making sacrifices, and continued practice as characteristics of a persistent student who would do well in STEM. Some attitudes that stakeholders conceived as essential were going above and beyond the classroom in pursuit of STEM learning and a belief that STEM helps develop critical thinking skills. Implications for this study include STEM programs at the middle and high school level using this instrument to assess the efficacy of the STEM education programs that change the attitudes and develop persistence towards learning and doing STEM and triggering conversations in classrooms focused on STEM careers and collaborations with STEM professionals. [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.]