Tertiary assessment policy and practice address multiple purposes that can both complement and contradict one another. This mixed-method study employing both quantitative and qualitative data builds on the results of a large-scale survey of academic staff and student conceptions of assessment with a follow-up analysis of staff comments, systematic review of institutional policy documents and individual interviews with senior academic managers. Institutional policy patterns are evaluated in light of issues emerging from the survey data as well as the international research literature. Based on the findings, the article concludes with recommendations for the design of quality policy and practice guidelines to ensure that tertiary assessment is manageable, valid, equitable and has the integrity required by stakeholders in higher education institutions.