This chapter reviews the theoretical and empirical issues dealing with Social Security pensions. The first part of the chapter discusses pure pay-as-you-go plans. It considers the effects of introducing such a plan on the present value of consumption, the optimal level of benefits in such plans, and the empirical research on the effects of pay-as-you-go pension systems on labor supply and saving. The second part of the chapter discusses the transition to investment-based systems, analyzing the effect on the present value of consumption of such a transition and considering such issues as the distributional effects and risk associated with such systems.
