[dsacco]

I think the fact that they're phenomenal is pretty clear, but I think a more important question is how reliable the returns are. They might be reliable, but that doesn't seem obvious to me from the comments in this thread, and it's still not clear to me that YC is capable of catapulting an arbitrary company in their set to wild success ("kingmaking") or that they're capable of repeating those successes over the long term.

[austenallred]

They have consistently pumped out many of the top companies in Silicon Valley for over 10 years now. Most of the companies are newer, as always, and I don’t think YC would claim they can pick any random company and make them successful, but if YC isn’t a “kingmaker” then there’s no such thing in Silicon Valley.

[DoreenMichele]

It was found that 90 percent of the small businesses fail within one year.

http://smb-trends.com/2011/02/smb-failure-rate-us/

Out of 1280 YC companies, only 139 are listed as dead. Without pulling out a calculator to determine an exact figure, that roughly flips that figure from 90% failure rate to a near 90% success rate. And actually it is worse than that because the 90% failure rate is in the first year and the near 90% success rate for YC is an "all time" figure for the history of YC.

http://yclist.com