[vangale]

OT but can be filed under "Falsehoods programmers believe about Social Security Numbers": SSN's are unique per person.

A friend of mine worked on a shareholder database for AT&T back in 70/80's and discovered this when they tried to make their SSN column unique.

[walshemj]

Why does AT&T need to store SSN's at BT improper use of NI numbers was a gross misconduct case.

[toast0]

AT&T issues dividends to shareholders. Dividends are taxable, and must be reported to the IRS with the shareholders' tax ID.

Now, AT&T also asks for account holders' tax ids, which the use to pull credit reports, and to report on credit activity.

[KekDemaga]

Multiple accounts belonging to a single person, or the same SS number for different people?

[vangale]

Same SS for multiple living people. It's also kind of amazing that the AT&T shareholder database was large enough to have dupes.

[mywittyname]

Doesn't the birthday paradox/pigeonhole principle apply here? If we assume that there are 1,000,000,000 unique values, then the square root of a billion (31,622) is all you need for a 50% chance of collision.

[smudgymcscmudge]

That's only if SSNs are randomly assigned. They aren't.

The issue is people are giving AT&T incorrect SSNs.

[selectodude]

Post-2011 they started making them random.

[specialist]

Name + DOB + SSN are mostly unique. No guarantees.

[undersuit]

Throw in Place of Birth and cross your fingers.

[dredmorbius]

I'd addressed that a week or few back regards account security questions. A big problem is that there are only so many place names in any country, and of those, a relatively small set with birthing centres.

There are 248 birthing centers in the United States, and only about 1% of all births occur outside of one (typically a BC is at a hospital).

https://www.cdc.gov/nchs/data/databriefs/db144.htm

[TheCoelacanth]

I think you are reading that wrong. There are 248 freestanding birthing centers that are not attached to hospitals. 0.4% of births occur in birthing centers. 0.9% occur at home. 98.6% of births occur in hospitals. There are >5000 hospitals in the US.

[dredmorbius]

A survey or count of maternity words, or labour & maternity centres, or ... whatever else they're called now ... is rather hard to come by.

This long HuffPo piece profiling the problem ... manages to specifically fail to answer that question, though it does note that "more than half of all rural counties in this country are now without a single local hospital where women can get prenatal care and deliver babies."

https://outline.com/JPgKaS

This list suggests there are 1627 rural counties in the US. So at least 814 of them lack a birthing facility (hospital, clinic, etc.) of some stripe.

http://files.consumerfinance.gov/f/201410_cfpb_final-list-ru...

There are 3,142 counties total in the US.

https://en.m.wikipedia.org/wiki/List_of_United_States_counti...

[dredmorbius]

Ah, that could very well be the case, as the number sounded somewhat absurdly low. I was trusting in the source, and definitions weren't particularly clear.

I'm not sure every "hospital" itself has a maternity ward, given my familiarity with several specifically in outlying areas (many are not much more than glorified first-aid stations, without permanent resident physician staff -- that happens to be how I'm principally aware of them).

But we're down to something on the order of 2500 - 5000 facilties, now, which remains a pretty low count.

[C4K3]

Doesn't the SSN already encode the general area where it was issued (usually place of birth?)

https://www.ssn-check.org/decode/

[dredmorbius]

It did, by office (through 1972) or ZIP Code (through 2011), but not any longer.

If you are on HN and have a randomly-assigned Area Number on your SSN, you are, however, precocious.