"Music is both a creative and a performing art" (Hallam, 2006, p. 70). Many musicians and music educators maintain that composing and performing, although related, are essentially different aspects of musical activity. In the professional musical sphere, composition and performance are almost invariably separated; academic studies have treated them discretely; GCSE and "A" level specifications assess them distinctly, and many music teachers assess them in the classroom as if they were separate disciplines. It is common practice for students in the lower secondary school in England to work in a more integrated way, however (Philpott, 2001; Major, 2008), composing, performing to the class, and appraising each others' work. Recently produced assessment guidelines for secondary school music teachers in England (NAME, 2011) encourage this more integrated view, accepting the assumption made by Swanwick and Franca (1999, p. 12) that "musical understanding is a broad conceptual dimension" by considering composing and performing as inter-linked ways of demonstrating and communicating musicality. This study sets out to investigate the links between composing and performing in the secondary school classroom, through peer-rating, teacher rating and students' self-report attitudinal questionnaires, analysing these using a multi-trait, multi-method technique.