Bob Stoll: the man who shook up Vegas (2007)

For starters, I don't see any difference between Bob Stoll's publishing his handicapping analyses and Wall Street analysts publishing their analyses. Well, I actually see one difference: Bob Stoll is probably more trustworthy than a Wall Street analyst.

It's tempting to think of investing as tossing coins, i.e., as random experiments. If that were the case, then, yes, after 20 years of consistent results there would still be a small chance that such success were due to luck.

However, investing is not tossing coins. The market changes all the time, so, in fact, one is not playing the same random experiment over and over again. One is playing different random experiments each day, and each day is pretty much unique.

Let us not get carried away by probability and statistics here. Probability is a way of dealing with uncertainty. Lacking information, one assumes a priori that the probability that the coin toss will he heads / tails is 0.5, but that's just a model, it's not the real world.

If you toss the coin using a mechanical device that applies always the same force to the coin, and that is rigidly attached to a table, for instance, then you don't have a random experiment. You have a reproducible experiment. Knowing the force applied to the coin, and the geometry of the problem, you can solve Newton's equations and fluid dynamics equations to predict how the coin will land. There's still uncertainty and error, but I doubt the probabilities will still be 50% heads and 50% tails if you toss the coin always the same way using the mechanical device. Stanford professor Persi Diaconis wrote a beautiful paper on it years ago...

So, if coin tossing in the real world is not even a true random experiment, how can investing be?????

I used to be a trader. Let me tell you. Trading is not coin tossing. Trading is basically legalized piracy. It requires skill. So does investing.