why do we have a social security number
Social Security number The original purpose of this number was to track individuals' accounts within the Social Security program. It has since come to be used as an identifier for individuals within the United States, although rare errors occur where duplicates do exist. As numbers are now assigned by the central issuing office of the SSA, it is unlikely that duplication will ever occur again. A few duplications did occur when prenumbered cards were sent out to regional SSA offices and (originally) Post Offices.