The industry, as expected, claims they do. As a University of Chicago product, I am generally skeptical of claims that hedge funds, on average, produce alpha. It is certainly possible that the extra returns (if there are any) are due to increased risk. From the NYT:
Based on Mr. Malkiel’s studies and other academic work, hedge fund investors should probably assume that reported industrywide returns are really as much as four percentage points lower, which makes hedge fund managers look much less special. This problem of voluntary reporting adds to what is known as survivorship bias, by which poorly performing funds that shut down drop out of the index.
It is still tough to say what this ultimately proves, but it seems clear that until more transparency is adopted in the industry, one should be skeptical of the claim that hedge funds, on average, produce higher risk adjusted returns than alternative investments.
I am not sure how I feel about the skills of individual managers. It is true that some managers might produce superior returns consistently due to their investing skill, but it is hard to know for sure. For mutual funds at least, Eugene Fama has found that just by luck alone, there should be more successful managers than exist today. But the jury is out on hedge fund managers. Of course, if you are a hedge fund manager collecting your 2/20 fees, transparency is the last thing you want. That is what regulation is for though.
Full Disclosure: If someone was willing to give me a chunk of money with a 2/20 fee structure to try to produce alpha, I would give it my best shot. Of course, I am arrogant so I think I could do it, but people always overestimate their own abilities.