Summary

Under the current Social Security benefit formula, retired workers receive benefits that equal about 50 percent of pre-retirement earnings for a low-wage worker but only about 30 percent for a relatively high-wage worker. Factors other than earnings also influence the distribution of benefits, including the program's provisions for disabled workers, spouses, children, and survivors. Changes in the program over time also affect the distribution of benefits across generations. Social Security faces a long-term structural financing shortfall. Program changes to address that shortfall could alter the way Social Security's benefits and revenues are distributed across the population and affect the income security of millions of Americans. To gain a better understanding of the distributional effects of potential program changes, the Chairman and Ranking Minority Member of the Senate Special Committee on Aging asked us to address (1) how to define and describe "progressivity," that is, the distribution of benefits and taxes with respect to earnings level, when assessing the current Social Security system or proposed changes to it; (2) what factors influence the distributional effects of the current Social Security program; and (3) what would be the distributional effects of various reform proposals, compared with alternative solvent baselines for the current system.

Two distinct perspectives on Social Security's goals suggest different approaches to measuring "progressivity," or the distribution of benefits and taxes with respect to earnings level. Both perspectives provide valuable insights. An adequacy perspective focuses on benefit levels and how well they maintain pre-entitlement living standards. An equity perspective focuses on rates of return and other measures relating lifetime benefits to contributions. Both perspectives examine how their measures are distributed across earnings levels. However, equity measures take all benefits and taxes into account, which is difficult for reform proposals that rely on general revenue transfers because it is unclear who pays for those general revenues. The Social Security program's distributional effects reflect both program features and demographic patterns among its recipients. In addition to the benefit formula, disability benefits favor lower earners because disabled workers are more likely to be lower lifetime earners. In contrast, household patterns reduce the system's tilt toward lower earners, for example, when lower earners have high-earner spouses. The advantage for lower earners is also diminished by the fact that they may not live as long as higher earners and therefore would get benefits for fewer years on average. Proposals to alter the Social Security program would have different distributional effects, depending on their design. Model 2 of the President's Commission to Strengthen Social Security proposes new individual accounts, certain benefit reductions for all beneficiaries, and certain benefit enhancements for selected low earners and survivors. According to our simulations, the combined effect could result in lower earners receiving a greater share of all benefits than promised or funded under the current system if all workers invest in the same portfolio.