Verbooy, K., Hoefman, R., van Exel, J. and Brouwer, W. (2018). Time is money: Investigating the value of leisure time and unpaid work Value in Health, 21(12):1428--1436.

Objectives Lost unpaid work and leisure time of patients due to ill health often are not included in economic evaluations, even in those taking a societal perspective. This study investigated the monetary value of unpaid work and leisure time to enable the inclusion of patient time in economic evaluations. Methods A contingent valuation study was performed to derive monetary values of unpaid work and leisure time. Data were collected with an online survey among a representative sample of people 18 years and older in the Netherlands in terms of age, sex, and educational level in January 2014 (n = 316). Willingness-to-accept (WTA) and willingness-to-pay (WTP) values were analyzed with a two-part model. First, a logistic regression model investigated the willingness to trade in the WTA/WTP tasks. Second, a log-transformed ordinary least squares regression model analyzed the level of positive WTA and WTP values. Results The average WTA value for unpaid work was €15.83, and the average WTA value for leisure time was €15.86. The mean WTP value for leisure time was €9.37 when traded against unpaid work, and €9.56 when traded against paid work. Differences in monetary values of unpaid work and leisure time were partly explained by respondents{\textquoteright} income, educational level, age, and household composition. Conclusions Researchers can adhere to the societal perspective by also including the value of hours of lost unpaid work and leisure time in economic evaluations. As a first indication of its value, we suggest applying the WTA value of €16.