Could it be the military started something that was taken up by other institution?
I think it has more to do with computer systems databases
Your SS# is only yours(Hah), it's really only the last 4 digits.
The college I work for it is also the student ID, creating file problems for our alien students. Your only number is not correct for all those who are or have gone through process of becoming a citizen.
I had to get them for Girls as soon as they were born so the state could keep track of some my student aid stuff. Next year I will do a search on all 3 of our numbers for social security earned, to make sure mine is still fixed & there has none.
In the early 80's the IRS figured out that SS administration had issued my origanal # to 5 women of assorted ages, in different areas of the US. Our first,last & middle names, birth day & month were the same. At least the first one sort of made sense even our fathers first & last names were the same(both very common)
It's made me slightly paranoid about SSA information, not that I expect there to be any money for me or the girls to collect when were of age.
CJ
