NBER Publications by Jae Song

This paper uses Social Security Administration longitudinal earnings micro data since 1937 to analyze the evolution of inequality and mobility in the United States. Earnings inequality follows a U-shape pattern, decreasing sharply up to 1953 and increasing steadily afterwards. We find that short-term and long-term (rank based) mobility among all workers has been quite stable since 1950 (after a temporary surge during World War II). Therefore, the pattern of annual earnings inequality is very close to the pattern of inequality of longer term earnings. Mobility at the top has also been very stable and has not mitigated the dramatic increase in annual earnings concentration since the 1970s. However, the stability in long-term earnings mobility among all workers masks substantial heterogeneity...

The Social Security Amendments of 1983 reduced the generosity of Social Security retired worker benefits in the U.S. by increasing the program's full retirement age from 65 to 67 and increasing the penalty for claiming benefits at the early retirement age of 62. These changes were phased in gradually, so that individuals born in or before 1937 were unaffected and those born in 1960 or later were fully affected. No corresponding changes were made to the program's disabled worker benefits, and thus the relative generosity of Social Security Disability Insurance (SSDI) benefits increased. In this paper, we investigate the effect of the Amendments on SSDI enrollment by exploiting variation across birth cohorts in the policy-induced reduction in the present value of retired worker benefits. ...