Table 2.

Steps to estimate caregiver informal care cost of illness using the Caregiver Indirect and Informal Care Cost Assessment Questionnaire

Step 1	Calculate total number of hours of paid informal care
	The first step to estimate caregiver informal care cost is to calculate the number of hours of paid informal care per week. These data are recorded in Question 9. To obtain the annual number of hours of paid informal care, the weekly data are multiplied by 52, assuming that the care is provided throughout the year
Step 2	Calculate total number of hours of unpaid informal care
	The second step is to calculate the total number of hours of unpaid informal care per week. These data are recorded in Question 10 through Question 13. To obtain the annual number of hours of unpaid informal care, the weekly data are multiplied by 52, assuming that the informal care is provided throughout the year. The calculated number of hours of unpaid informal care may be adjusted to allow for a minimum time for basic needs (e.g., eating, sleeping, and toileting) of 6 h per day
Step 3	Valuation and estimation
	Opportunity cost method The third and last step to calculate informal care cost is to multiply the calculated hours of unpaid informal care by the chosen opportunity cost of leisure time (e.g., 35% of the national mean gross wage according to the value of travel time savings [22]). Paid informal care (calculated in Step 1) is valued at the cost of employment Proxy good method The third and last step to calculate informal care cost is to multiply the calculated hours of unpaid informal care by the chosen market substitute costs. Paid informal care (calculated in Step 1) is valued at the cost of employment