Just How Wise Is the Sage of Omaha?

In fact, this is a question that people have been asking about the Warren Buffett of financial markets.  After all, someone has to be the outlier in the distribution: how do we know that it is skill, rather than luck, which has landed Warren Buffett in his current enviable position? For years, people have been arguing about whether Buffett actually beats the markets through sheer financial acument, or whether he's simply the guy at the far right-hand side of the probability distribution--a coin flipper who looks, through accident of fate, like a stock-picking genius.