In recent years, research and practice focused on academics and students working in partnership to co-design learning and teaching in higher education has increased [Deeley and Bovill 2017. 'Staff student partnership in assessment: enhancing assessment literacy through democratic practices.' "Assessment & Evaluation in Higher Education" 42 (3): 463-477. doi:10.1080/02602938.2015.1126551]. Student generation of content has been advocated as a means of fostering deep learning and high levels of students engagement, leading to enhanced conceptual understanding [Draper 2009. 'Catalytic Assessment: Understanding how MCQs and EVS can Foster Deep Learning.' "British Journal of Educational Technology" 40 (2): 285-293.]. However, within the discourse exploring staff-student co-creation, some concerns have been raised about whether students ought to, or indeed can, meaningfully act as partners in assessment [Cook-Sather, Bovill, and Felten 2014. "Engaging Students as Partners in Learning and Teaching." San Francisco, CA: Jossey Bass.]. This paper describes the introduction of a co-creation assignment into an undergraduate tax module. Students' and instructors' perceptions of several aspects of the assignment were examined, facilitating the cataloguing and elucidation of the tensions involved in assessment co-creation. The paper suggests techniques to manage these challenges effectively, thereby providing a case study for others with an interest in implementing assessment co-creation within their own disciplinary context.