Reminiscences of a Stockblogger (I don’t know his real name) has an excellent post on identifying what makes your edge in the marketplace. His performance has been excellent and his following paragraph resonates with me:
I think I have put up enough years of out-performance to tentatively conclude I have some sort of edge. Its still possible that I don’t; maybe I will blow up yet and these past years will prove to be a statistical aberration. But as times goes on those odds become less likely.
His performance is exceptional when you consider the number of positions he has in his portfolio – I run a much higher concentration than he does. It could be that my historical performance is simply a fluke.