The study investigates criteria chosen by music students for peer and self assessment of both the rehearsal process and performance outcome of their rock groups. The student-chosen criteria and their explanations of these criteria were analysed in relation to Birkett's skills taxonomy of "soft" and "hard" skills. In the rehearsal process, students placed an emphasis on "soft" skill issues, and in the performance outcome, on "hard" skill issues. For students and staff, challenges raised include understanding how and whether to assess "soft" skills; that there is a continuum of "soft" and "hard" skills rather than a binary; and ensuring clear understanding of criteria terms.