[영문]A fundamental element of the debate over Social Security reform is which set of principles should describe the role of the program over the next century. One possibility, which we refer to as qqqquot;collectivist principles,qqqquot; emphasizes the economic efficiency gains that flow from a social insurance program designed to pool various risks across all workers in the economy. A second possibility, which we label qqqquot;individualist principles,qqqquot; points to potential efficiency gains from reducing the degree of government intervention and increasing individual self?determination.