The iMTA Productivity Cost Questionnaire: A Standardized Instrument for Measuring and Valuing Health-Related Productivity Losses.

Background: Productivity losses often contribute significantly to the total costs in economic evaluations adopting a societal perspective. Currently, no consensus exists on the measurement and valuation of productivity losses.

Objective: We aimed to develop a standardized instrument for measuring and valuing productivity losses.

Methods: A group of researchers with extensive experience in measuring and valuing productivity losses designed an instrument suitable for self-completion, building on preknowledge and evidence on validity. The instrument was designed to cover all domains of productivity losses, thus allowing quantification and valuation of all productivity losses. A feasibility study was performed to check the questionnaire's consistency and intelligibility.

Results: The iMTA Productivity Cost Questionnaire (iPCQ) includes three modules measuring productivity losses of paid work due to 1) absenteeism and 2) presenteeism and productivity losses related to 3) unpaid work. Questions for measuring absenteeism and presenteeism were derived from existing validated questionnaires. Because validated measures of losses of unpaid work are scarce, the questions of this module were newly developed. To enhance the instrument's feasibility, simple language was used. The feasibility study included 195 respondents (response rate 80%) older than 18 years. Seven percent (n = 13) identified problems while filling in the iPCQ, including problems with the questionnaire's instructions and routing (n = 6) and wording (n = 2). Five respondents experienced difficulties in estimating the time that would be needed for other people to make up for lost unpaid work.

Conclusions: Most modules of the iPCQ are based on validated questions derived from previously available instruments. The instrument is understandable for most of the general public.