Nonmusical factors affect the Virginia Band and Orchestra Directors Association (VBODA) concert performances and subsequent assessment results; namely, school size, ethnicity, and socioeconomic status. A comparison of ratings given by individual trained evaluators demonstrates interrater reliability. A comparison of final ratings given at different assessment locations and times reflects the reliability of ratings. However, administrators and evaluators must consider nonmusical factors to report instrumental music performance results accurately. Predictor variables included SES, school size, and minority percentage. Outcome variables included overall band rating and band performance literature difficulty. Using an MLR design, the researcher compared data from the 2019 VBODA Concert Assessment (sixteen districts) and Virginia Department of Education (school size, ethnicity, and free and reduced lunch). This quantitative research will improve the Concert Band Assessment, adjudicator training, in-service music teacher development, preservice music teacher training, and equity concerns for underserved populations. [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.]