From http://www.paulgraham.com/notnot.html :

"We have some evidence to support this. Several of the most successful startups we've funded told us later that they only decided to apply at the last moment. Some decided only hours before the deadline."

But copying that would be particularly cargo-cult-ish. The point there is that great people were uncertain, not that uncertain people were great. The thing to copy is the greatness, not the uncertainty. :-)

"Cargo Cult Software Engineering" should be required reading for all nerds:

http://stevemcconnell.com/ieeesoftware/eic10.htm

I applied early, so there are exceptions :)

I would agree this is difficult to quantify. It came from a casual conversation with YC folks.

that is funny kkkk Matt Marron first advice was: "Apply early. I’m guessing something like 75% of their applications are submitted in the last few days. That’s usually how those sorts of things work. Doing it earlier can only help get you a little more consideration time."

I could see that the best people put thought into the application process, begin writing early and hold off on actually submitting until close to the deadline.

-- I agree with this I think that preparation is an important thing.