The CIIQ 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). Clarifications have been introduced to improve internal consistency and reduce respondent burden, without altering the underlying estimands or conceptual definitions. Specifically, in the CIIQ 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 2.0 are therefore directly comparable with those estimated using earlier versions of the instrument.

Please note that the Stata, SAS, and R analysis procedures have also been updated following the release of the CIIQ 2.0. Using these updated procedures, all analyses and cost calculations (as outlined below) are performed automatically, ensuring consistent and reproducible estimation of caregiver indirect (productivity) and informal care costs.

Steps to calculate caregiver informal care costs using the CIIQ version 2.0

Step 1: Calculate total number of hours of informal care

The first step is to calculate the total number of hours of informal care per week. These data are collected in Questions 9–12, which record the total time spent providing informal care across four activity categories. Importantly, these questions capture total informal care time regardless of whether the caregiver was financially compensated or not.

To obtain the annual number of hours of informal care, weekly hours are multiplied by 52, assuming that care is provided throughout the year. Total informal care time may optionally be capped to allow for a minimum amount of time required for basic needs (e.g., eating, sleeping, and personal hygiene), typically assumed to be 6 hours 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, as reported in Question 13. These data capture the number of hours for which the caregiver received financial compensation for providing informal care.

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 derived by subtracting the total number of paid informal care hours (Question 13) from the total informal care hours reported in Questions 9–12. Paid informal care hours are subtracted proportionally across the four informal care activity categories (Questions 9–12), under the assumption that paid and unpaid care are distributed similarly across activities.

To obtain the annual number of hours of unpaid informal care, the weekly unpaid informal care hours are multiplied by 52, assuming that informal care is provided throughout the year.

Step 4: Valuation and estimation

The fourth and final step is to value the estimated paid and unpaid hours of informal care. The proxy good method and the opportunity cost method represent alternative valuation approaches and should not be applied simultaneously.

Proxy good method

Using the proxy good method, the cost of informal care is calculated by valuing annual unpaid informal care hours using the cost of an appropriate market substitute (e.g., a home care worker wage). Paid informal care hours are valued using the cost of employment.

Opportunity cost method

Using the opportunity cost method, the cost of informal care is calculated by valuing annual unpaid informal care hours using an opportunity cost of leisure time (e.g., a proportion of the national mean gross wage). Paid informal care hours are valued using the cost of employment.

Steps to calculate caregiver indirect (productivity) costs using the CIIQ version 2.0

Step 1: Calculate total work hours

The first step to estimate caregiver indirect (productivity) costs is to calculate the total number of work hours per week using data recorded in Question 2.

Step 2: Calculate productivity losses due to absenteeism and presenteeism

The second step is to estimate productivity losses arising from absenteeism and reduced productivity while working. Absenteeism is measured as the number of hours missed from work during the last week (Question 6). Hours missed from work are capped at contracted weekly work hours (Question 2). Presenteeism is estimated by transforming the reported loss in productivity from Question 7 into a proportion representing percent work impairment, which is multiplied by the number of hours actually worked during the week, calculated as contracted weekly work hours (Question 2) minus hours missed from work (Question 6). These components represent distinct forms of productivity loss and are retained separately for subsequent aggregation.

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 calculation applies only to caregivers who report having reduced their working hours due to the disease/condition of the relative (i.e., “Yes” on Question 4). The loss of work hours is calculated as the difference between previous weekly work hours (recorded in Question 5) and current contracted weekly work hours (recorded in Question 2). This loss represents an additional component of productivity loss attributable to reduced working hours and is retained separately for subsequent aggregation.

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 not currently employed (i.e., “No” on Question 1). This calculation applies only to caregivers who report having stopped working because of the disease/condition of the relative (i.e., “Yes” on Question 8). The loss of work hours is calculated using the number of previous weekly work hours recorded in Question 8. This loss represents an additional component of productivity loss attributable to stopping work completely and is retained separately for subsequent aggregation.

Step 5: Extrapolation

The fifth step is to extrapolate the weekly productivity loss estimates, derived from the applicable components described in Steps 2–4, to annual values using external data on the country‑specific mean number of work weeks per year. In the absence of country‑specific data, a value of 48 working weeks per year is commonly used.

Step 6: Valuation and estimation

The sixth and final step is to value the estimated annual productivity losses. The proxy good method and the opportunity cost method represent alternative valuation approaches and should not be applied simultaneously.

Proxy good method

Under the proxy good method, informal care is regarded as productive work. In practice, the overlap between informal care and lost work hours is calculated by assuming that a specified proportion of weekly informal care time occurs during potential working time. By default, full overlap may be assumed (i.e. all informal care time is eligible to replace lost work hours), while alternative assumptions such as 5/7 may be applied in sensitivity analyses to reflect caregiving distributed evenly across the week. The annual value of productivity losses is obtained by valuing the estimated annual productivity losses using the cost of employment. The value of informal care that temporally overlaps with and replaces lost work hours (calculated separately) is subtracted from the total value of productivity losses. This adjustment applies to productivity losses due to absenteeism, reduced working hours, and stopping work completely. Productivity losses due to reduced productivity while working (presenteeism, calculated in Step 2 based on Question 7) are not adjusted, as they occur during hours actually worked and therefore do not represent the same time as informal caregiving hours. Indirect costs are bounded at zero.

Opportunity cost method

Under the opportunity cost method, informal care is not regarded as productive work. The annual value of productivity losses is obtained by valuing the estimated annual productivity losses using the cost of employment. The value of informal care is therefore not subtracted from the total value of productivity losses. Productivity losses due to absenteeism and reduced productivity while working are included in full.