Assessment is central to learning. It is also central to the cost of providing higher education. Choosing how much and what forms of assessment are questions not only of good teaching but of good policy. Measuring the amount of assessment set in each course provides a basis on which to determine equitable and appropriate workloads for students and staff across disciplines and institutions and to use institutional budgets and staff time to best effect. It is, however, more difficult than it might at first appear to select metrics appropriate to this task. This article considers the advantages and disadvantages of four options. It also suggests the potential value of ratios and proposes that further consideration be given to removing the distinction commonly found in student workload formulae between time spent on learning out of class and that spent on assessment.