Social insurance for the elderly is judged responsible for the widely observed trend towards early retirement. In a world of laissez-faire or in a first-best setting, there would be no such trend. However, when first-best instruments are not available, because health and productivity are not...

This paper studies the role of social insurance as a redistributive mechanism in the presence of an optimal (linear or general) income tax. It considers a second-best setting with two unobservable individual characteristics: ability, measured by the wage rate, and risk, measured by the...