The incorporation of informal care into economic evaluations of health care is troublesome. The debate focuses on the valuation of time spent on informal caregiving, while time measurement, a related and may be even a more important issue, tends to be neglected. Valid time measurement is a necessary condition for the valuation of informal care. In this paper, two methods of time measurement are compared and evaluated: the diary, which is considered the gold standard, and the recall method, which is applied more often.
