OBJECTIVES : The cost of productivity losses is one of the essential factor in an economic evaluation from societal perspective. Many instruments have been developed to measure health-related productivity losses directly from patients. The objective of this study was to identify and compare the productivity loss instruments valuing absenteeism, presenteeism, and unpaid work.

METHODS : We identified relevant instruments using three steps of search strategies. First, we searched review articles related to the instruments of productivity loss using combinations of keywords (productivity, loss, cost, review, questionnaire, and instrument) in Google Scholar during 1990-2019. Second, we selected three large reviews through the title/abstract screening. Finally, we identified and reviewed four instruments measuring and valuing productivity losses of absenteeism, presenteeism and unpaid work. We compared the characteristics (including format of questionnaire, recall period, target population, and measurement/valuation of productivity losses) of each instrument.

RESULTS : Four instruments (Work Productivity and Activity Impairment, WPAI; Health and Labour Questionnaire, HLQ; Valuation of Lost Productivity Questionnaire, VOLP; iMTA Productivity Cost Questionnaire, iPCQ) consisted of different formats and recall periods (1 week for WPAI, 2 weeks for HLQ, 4 weeks for iPCQ. 3 months for absenteeism of VOLP and 1 week for presenteeism/unpaid work of VOLP). All of those targeted general population. Those employed different approaches (human capital approach and friction cost approach) to measure the cost of productivity losses. Three instruments (HLQ, VOLP, and iPCQ) can measure the cost of the three main factors of productivity losses (absenteeism, presenteeism and unpaid work), while WPAI can only measure the cost of absenteeism and presenteeism.

CONCLUSIONS : There is no consensus on what is the best instrument to measure and monetarize the health-related productivity losses. When measuring the cost of productivity losses in an economic evaluation, researchers should consider the characteristics of each instrument.