Birth location =/= mailing address zipcode. Babies are usually born in hospitals, and thus parents from many areas concentrate in one specific building. When you re-distribute these births out to their respective homes around the county, the zip code becomes much more important.

I used my mailing address zipcode, without even realizing it wasn't my birth zipcode :)

Where are you searching for your zip code and birth date? I couldn't find anything on the Data Privacy Lab site. :\

In towns like mine, however, 40,000 people share the same zip code with the hospital. I'm sure there are quite a few more town like mine throughout the US.

Okay, well let's do the math:

US pop in 2000: 280,000,000 — US births in 2000: 4,000,000 — US births per day: 10,958 — Fraction of US pop that 40,000 represents: 0.0001428 — Number of births per day for the 40,000: 1.56

That seems inline with the conclusion of the paper. See any mistakes?

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 is actually in the top 100 of birthdates by frequency of births, according to the best data table I have seen on the subject.

http://www.nytimes.com/2006/12/19/business/20leonhardt-table...

Of course February 29th is dead last in frequency. Most early October birthdays are above the median in frequency.

Note the group of high rankings from 8-Sep, tailing off in early October - all those NYE babies ;)

also interesting is looking at the next lowest frequency dates-- all of them are clustered around major holidays:

365 12 25

364 1 1

363 12 24

362 1 2

361 7 4

360 12 26

359 11 28

358 11 27

357 11 26

356 1 3

355 10 31

354 12 23

353 11 25

352 11 24

Not sure if this is the (whole) reason, but obviously no one is going to have a scheduled induction or C-section on a holiday.

These days it doesn't surprise me, it seems like doctors are willing to induce at the drop of the hat these days. So why not to keep their holiday clear.

Interesting probabilities on x random people sharing the same birthday:

http://en.wikipedia.org/wiki/Birthday_problem

As another October 8th birthdate with the opposite impression of how many October kids there are, I had to look this up.

8.62% of all live births in the US during 2006 occurred during October [1]. No single month deviated significantly from it's expected percentage.

[1] http://data.un.org/Data.aspx?d=POP&f=tableCode:55

I guess people be fuckin' all of the damn time.

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)?

That was my dad's bd. His best friend was also born in the day.

I too am having some problems digesting this. I think we are missing something.