“…However, as numerous studies have found, such as Lleras-Muney (2005), Meara, Richards, and Cutler (2008), Bound et al (2015), and Chetty et al (2016), mortality risk tends to decline with education and income. Taking the relationship between income and mortality as given, Sánchez-Romero and Prskawetz (2017), Bagchi (2019), and Bishnu, Guo, and Kumru (2019) each investigate how the progressivity of PAYG Social Security is impacted by differential mortality and show that the progressivity of PAYG systems is negatively impacted by mortality inequality. The general consensus from this literature is that mortality differentials have a significant impact on the economic efficiency of Social Security systems and therefore must be accounted for in the design of such programs.…”