The CIIQ version 2.0 retains the original conceptual framework for measuring caregiver indirect (productivity) and informal care costs as separate components from a societal perspective, as described in Landfeldt et al. (2018). However, clarifications have been introduced to improve internal consistency and reduce respondent burden. Specifically, in the CIIQ version 2.0, total informal care time is recorded first, and paid informal care is subsequently identified as a subset, with separation handled analytically. The underlying conceptual framework, valuation methods, and data requirements remain unchanged. Estimates derived using the CIIQ version 2.0 can still be directly compared with those estimated using earlier versions of the instrument.

Please note that the analysis procedures have also been updated following the release of the CIIQ version 2.0:

• SAS CIIQ v2.0 procedures

• R CIIQ v2.0 procedures

• Stata CIIQ v2.0 procedures

Caregiver indirect (productivity) costs

Step 1: Calculate total work hours including paid informal care

The first step to estimate caregiver indirect (productivity) costs is to calculate the total number of work hours per week, including hours that the caregivers are paid to care for their relative, using data recorded in Question 2 and Question 14.

Step 2: Calculate the loss of work hours while working

The second step is to estimate the loss of work hours while working (for caregivers who are employed). For this calculation, the recorded loss in productivity from Question 7 is transformed to a proportion representing percent work impairment/loss. This estimate is then multiplied by the number of work hours per week (recorded in Question 2) adjusted for the number of hours missed from work (recorded in Question 6). The calculated loss is then added to the number of hours missed from work (recorded in Question 6), which represents the total loss of work hours for caregivers employed full-time.

Step 3: Calculate the loss of work hours for caregivers employed part-time

The third step is to calculate the loss of work hours for caregivers who are employed part-time (i.e., No on Question 3). This should only comprise hours for caregivers who state that they reduced their working hours because of the disease/condition of the relative (i.e., Yes on Question 4). To calculate the loss of work hours, total work hours (calculated in Step 1) are subtracted from previous work hours (recorded in Question 5). This loss is then added to the number of hours missed while working (calculated in Step 2).

Step 4: Calculate the loss of work hours for caregivers not employed

The fourth step is to estimate the loss of work hours for caregivers who are unemployed (i.e., No on Question 1). This calculation should only comprise caregivers who state that they stopped working because of the disease/condition of the relative (i.e., Yes on Question 8). To calculate the loss of work hours, the number of hours of paid informal care recorded in Question 9 is subtracted from previous work hours recorded in Question 8.

Step 5: Extrapolation

The fifth step is to extrapolate the weekly data to annual estimates using external data on the country-specific mean number of work weeks per year.

Step 6: Valuation and estimation

The sixth and final step is to multiply the estimated total annual loss of work hours with the cost of employment. Using the proxy good method, the value of informal care (calculated in Table 2) must be subtracted from the total value of lost work hours (excluding costs associated with loss of work hours owing to lost productivity while working calculated in Step 2).

Caregiver informal care costs

Step 1: Calculate total number of hours of informal care

The first step to estimate caregiver informal care cost is to calculate the total number of hours of informal care per week. These data are recorded in Question 10 through Question 13 and comprise the total time spent providing informal care, stratified by activity category. This total includes both unpaid informal care and care for which the caregiver was financially compensated. To obtain the annual number of hours of informal care, the weekly data are multiplied by 52, assuming that the care is provided throughout the year. The calculated number of hours of 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 2: Calculate total number of hours of paid informal care

The second step is to calculate the total number of hours of paid informal care per week. These data are recorded in Question 14. The total number of hours of paid informal care per week are used to derive unpaid informal care hours in Step 3.

Step 3: Calculate total number of hours of unpaid informal care

The third step is to calculate the total number of hours of unpaid informal care per week. Unpaid informal care hours are calculated as the difference between total informal care hours and paid informal care hours. Paid informal care hours are subtracted proportionally across the four informal care activity categories recorded in Questions 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.

Step 4: Valuation and estimation

Opportunity cost method

The fourth 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). Paid informal care is valued at the cost of employment.

Proxy good method

The fourth 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 is valued at the cost of employment.