“…However, conditional on a smooth age trend, the binary instrument indicating whether having reached certain specific age is unlikely to have an impact on people's voluntary work provision except through the channel of their retirement. Retirement induced by social security incentives is exogenous and has been used widely in the extant literature (Bonsang et al, 2012;Stancanelli and Van Soest, 2012;Eibich, 2015;Zhu and He, 2015;Kampfen and Maurer, 2016;Zhu, 2016;Atalay et al, , 2020Fischer and Muller, 2020;Frimmel and Pruckner, 2020;Nguyen et al, 2020).…”