This is a study of the development and validation of a rubric to enhance performer feedback for undergraduate vocal solo performance. In the literature, assessment of vocal performance is under-represented, and the value of feedback from the assessment of musical performances, from the point of view of the performer, is nonexistent. The research questions guiding this study were 1) What are the appropriate performance criteria, learning outcomes, and meaningful descriptors for various levels of proficiency for undergraduate solo vocal performance? and 2) How do students perceive their use of the feedback from the solo vocal performance rubric to improve future performances? The three groups of stakeholders of the project were voice professors from the research institution who assisted in the development of the rubric; students from the research institution who provided performance excerpts and shared their perceptions about the quality of the feedback; and voice professors from outside the research institution who used the rubric to assess the student performances. Mixed-methods participatory action research was the method used to conduct the study. Interviews with five experts aided the development of a criteria-specific rubric, which defined performance criteria, learning outcomes, and meaningful descriptors for various levels of proficiency for undergraduate students of singing. The rubric was distributed, along with 20 recordings comprised of 14 students, two professionals, and four repeated student performances, to voice professors who used the rubric to score the performances and provided feedback about the instrument as well as the process. Results of scoring were shared with student performers and interviews conducted about usefulness of the feedback. Seven themes emerged from the research analysis: a) levels of proficiency, b) performance criteria, c) descriptors, d) numerical scoring, e) comments, f) recording method, and g) song selection relative to the skill level of the singers. Results of the study determined that the rubric was statistically reliable, and the students received valuable feedback that validated their own self-perceptions and assisted them in long- and short-term goal setting. Practitioners may benefit from further research that explores the validity of the rubric when assigning a grade, assessing live performances, and including additional repertoire. [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.]