It's unclear whether he's getting better than random results. You're assuming the consequent.
It's well-known that the most successful startup in a group of startups is likely to earn more in profit than all the rest combined. We're here on HN talking about PG because YC has been the most successful of all incubators. However, there's always going to be one incubator that significantly outperforms all the others as a result of the distribution of startup success.
I don't know enough about how well PG's investments have done to make informed judgments, but only a very select few people are likely to have that info. I suspect those people have also done their due diligence to figure out if YC is a value-add compared to other incubators (it should be possible to do this without a convoluted double blind experiment), but anyone who's not them really can't say for sure that that's the case.
It's well-known that the most successful startup in a group of startups is likely to earn more in profit than all the rest combined. We're here on HN talking about PG because YC has been the most successful of all incubators. However, there's always going to be one incubator that significantly outperforms all the others as a result of the distribution of startup success.
I don't know enough about how well PG's investments have done to make informed judgments, but only a very select few people are likely to have that info. I suspect those people have also done their due diligence to figure out if YC is a value-add compared to other incubators (it should be possible to do this without a convoluted double blind experiment), but anyone who's not them really can't say for sure that that's the case.