While a subset of the costs of morbidity such as loss of working capacity or the cost of hospitalisation can be reliably measured on the basis of available data, other notions such as disability-adjusted life years (DALY) or the value of a life year lost (VOLY), a composite of the economic cost of morbidity and of mortality, are more fragile. There is also the risk of doubly penalising people exposed to social costs, e.g. air pollution, by treating their subsequent deaths as less valuable, as a DALY method yields a lower value on reductions in mortality risk for older populations with lower quality of life. These are ongoing issues where current economic research on costs of morbidity still needs to converge on a widely accepted metric for morbidity that would be comparable to the VSL established for measuring the social costs of increased mortality risk in the context of full cost accounting.