Abstract
I develop a general equilibrium life cycle model with an intensive and extensive margin of labor supply and endogenous human capital accumulation. I use the model to assess the effects of changes to various features of social security on labor supply outcomes. Of particular interest are changes to the scale of the program and to the relevant eligibility rules. I find that the cross-country differences in social security programs account for at least 79% of the differences in employment rates of people aged 55-64 and 17-31% of the differences in aggregate hours worked between the US and continental Europe.