​(Note from José Piñera. Martin Feldstein was my professor during my PhD. studies at Harvard, 1970-1974. His 1974 paper, "Social Security, Induced Retirement, and Aggregate Capital Accumulation", published in the Journal of Political Economy, helped me on my thinking on this key issue since it revolutionized how economists view retirement systems. He argued that Social Security depresses private saving because people rely on future government benefits instead of building their own wealth. Feldstein concluded that the U.S. Social Security system cut personal saving by about 50 percent. This reduction in saving limits the amount of money available for businesses to invest and grow the economy. Below his letter congratulating Chile’s Social Security privatization of 1980).