Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

87% of the U.S. Population are uniquely identified by {DOB, gender, zip}

latanyasweeney.org

Post reply on HN
Print view View original

71–80 of 102 posts

Re: 87% of the U.S. Population are uniquely identified by {DOB, gender, zip}

#71

Post by gwern »

jerf wrote: post #41
mikey_p wrote: post #2

While I find this fascinating, I'm sure this is old news to people in the business, like the people that run the grocery/chain store savings programs. What I'd be really interested to see is why this works, and what it tells us about distribution of population by zip code. I'd imagine the places where this doesn't work as well, are the most densely populated zip codes, where the likely hood of duplicates on the given…

Simple information theory; in a world of 6 billion people, 33 bits serves to uniquely identify anyone. 33 bits is a really low bar. It works because it can't hardly help but to work, sort of like the birthday paradox. In the US with approx 312 million (wikipedia) that's approximately 28.2 bits. It doesn't tell us much about zip code distribution because zip codes are chosen to have approx the same number of people in…

> Simple information theory; in a world of 6 billion people, 33 bits serves to uniquely identify anyone. 33 bits is a really low bar. It works because it can't hardly help but to work, sort of like the birthday paradox. In the US with approx 312 million (wikipedia) that's approximately 28.2 bits.

It's a powerful idea. I wrote a whole essay analyzing the anime _Death Note_ using the 33 bits idea (http://www.gwern.net/Death%20Note%20Anonymity) and I'm sure that's not even the tip of the iceberg.

Re: 87% of the U.S. Population are uniquely identified by {DOB, gender, zip}

#72

Post by zeratul »

nkassis wrote: post #66
tlb wrote: post #64

Earlier quoted context omitted.

But if you poll the database every day to see when age increases, you can get DOB.

Well... if the records are released I don't think they should change. Someone record at 50 isn't the same as at 60. Unless these are live datasets.

Correct you would not be able to guess the date of birth - the date of visit is removed.

Re: 87% of the U.S. Population are uniquely identified by {DOB, gender, zip}

#73

Post by jeffreymcmanus »

steve-howard wrote: post #60
jeffreymcmanus wrote: post #45

True unique identifiers are immutable. At least two of those three things can be changed.

Gender is a bit of a stretch, if technically changeable. I don't know much on the subject but I would wager that the proportion of people who have changed gender is not statistically significant enough to change the 87% figure.

Identifiers are either immutable or they're not. They can't be sorta-kinda immutable.

Re: 87% of the U.S. Population are uniquely identified by {DOB, gender, zip}

#75

Post by EwanG »

Then there are those of us who have unique enough names that you can pretty much look us up and find there's only two in the whole US (and we're related). Having been a DBA at one point, it's always fun to tell folks that "really, if you just search for my name I guarantee you'll find me faster". Heck in most cases a search in a system that separates first and last names will let me be found with just my first name. If it weren't for that lousy Welsh actor, that would work on Google also (although full name turns me up as most of the front page).

My point is that this shouldn't be THAT surprising. I suspect full name and gender would uniquely identify a fair portion of the US as well. We're not as homogenous as some societies and I think this proves it...

Re: 87% of the U.S. Population are uniquely identified by {DOB, gender, zip}

#79

Post by mdda »

Zimahl wrote: post #18
kingkilr wrote: post #7

There were no other males, born on october 8th 1990, in Lakeview, Chicago. I'm a little flabbergasted, to be frank.

October 8th is an odd date. Since it's my birthday as well (long before 1990 though) I have taken note that I run across very few with that birthday, let alone early October birthdays. Is it statistically a low-birth month? I'd love to know. On a side note, Happy 21st Birthday in just over a month!

October 8th? It seems like a decent % of people share your birthday (me among them). Certainly feels like a weird to me. How many thousand people read a page (given that it has a moderate up-vote)?

Re: 87% of the U.S. Population are uniquely identified by {DOB, gender, zip}

#80

Post by geboyr »

jeffreymcmanus wrote: post #45

True unique identifiers are immutable. At least two of those three things can be changed.

Do we know if she took into account population migration / movement? Looking at the description it doesn't look like it, but I'd be really curious to see how that affects the stat. Or how the stat changes if the zip code is tied to the person's DOB. In that scenario it probably drops a lot, because (I'm assuming) most people are born in a hospital, and there isn't a hospital in every zip code. So to my first comment on population movement, maybe that's actually a representation of the effect of population migration / movement. Cool.
Post reply on HN