Earnings Inequality and Mobility in the United States: Evidence from Social Security Data since 1937
利用1937年以来的社会保障纵向微观数据，分析了美国年度收入不平等呈U型变化，短期流动性稳定，长期流动性上升主要由女性推动，而高收入群体流动性未缓解收入集中度上升。
This paper uses Social Security Administration longitudinal earnings micro data since 1937 to analyze the evolution of inequality and mobility in the United States. Annual earnings inequality is U-shaped, decreasing sharply up to 1953 and increasing steadily afterward. Short-term earnings mobility measures are stable over the full period except for a temporary surge during World War II. Virtually all of the increase in the variance in annual (log) earnings since 1970 is due to increase in the variance of permanent earnings (as opposed to transitory earnings). Mobility at the top of the earnings distribution is stable and has not mitigated the dramatic increase in annual earnings concentration since the 1970s. Long-term mobility among all workers has increased since the 1950s but has slightly declined among men. The decrease in the gender earnings gap and the resulting substantial increase in upward mobility over a lifetime for women are the driving force behind the increase in long-term mobility among all workers. (c) 2010 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology..