There is a wealth of literature on people who participate in community instrumental ensembles. Studies exist regarding demographics, educational level, socio-economic status, music education experience, and musical self-identities of community music participants. Far less study focuses on young adults who were successful in high school programs but chose not to continue playing in a community instrumental ensemble group after the end of formal schooling. Traditional assumptions about their reasons—job and family for example—need to be examined. Attribution Theory, which provides a means of analyzing motivation for choices as well as perceived attributions for success or failure, was the theoretical framework of this research, with focus group interviews as the main procedural methodology. The geographic area of the study was limited to the greater Los Angeles area of southern California. Music education literature is replete with references to building skills and values for lifelong participation in music, whether in performance, in listening, or in engaging with music in other ways. This study will offer insight into why many young adults who were once in high school music choose not to continue in instrumental music performance beyond their high school years. I anticipate that this research may lead to better understanding of issues in young adult stages of life as they relate to choices about non-participation in community instrumental ensembles. This research suggests ways in which school music education can facilitate lifelong engagement with music, and will suggest how community ensembles might make changes that will broaden participation by a greater number of young adults after they leave school.