This study addresses the need to accurately assess social emotional learning from a quantitative perspective. As school districts evaluate the allocation of educational resources, data is used to inform those decisions. Social emotional learning (SEL) is gaining prevalence in the field of education. However, an accurate way to measure that learning is lagging behind. The goal of this study is to answer the question: What foundational elements are necessary for the development of a measurement instrument designed to address quantitatively student progress and mastery regarding social emotional learning in the music classroom? The focus has been narrowed down to the content area of music. The Arts Education & Social Emotional Learning Framework will be the lens through which these foundation elements are applied with emphasis on music performing ensembles. The Arts Education & Social Emotional Learning Framework is a powerful resource for educators seeking guidance on where the five Collaborative for Academic, Social, and Emotional Learning (CASEL) areas of competence intersect with the National Core Arts Standards for music. A model example of an assessment will be provided along with recommendations for how educators can build assessments on their own. [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.]