Tracy, most healthcare and insurance providers are moving away from SSN completely. I know that Blue Cross of CA completely reissued insurance cards mid-year last year to remove SSN in favor of their own ID. In deference to HIPAA, the healthcare industry is taking great pains to remove use of SSN.

And uniqueness is NOT guaranteed. (Yes, it drives the IRS and SSA nuts.) They've never made any bones about non-uniqueness, particularly dating from a time when the numbers were assigned regionally instead of centrally.


>I agree that an SSN should not be used as a PK, but it should be unique.