[danieltillett]

Do you have any evidence that the hit rate would be close to zero if you invested in founders with just a concept?

[pjlegato]

Yes. Y Combinator, which (very unusually) funds people with no track records and just a concept, has had only two really big successes (AirBnB and DropBox) in 11+ years and close to a thousand companies in the program.

http://yclist.com/