The difficulty in separating skill and luck is unconsciously illustrated by the author himself in his basketball example. We're asked to consider how much of a 'hot hand' is attributable to chance, and how much to skill. But what is chance in this context? Clearly he doesn't mean the likelihood of a ball launched in an arbitrary trajectory finding its way to the basket. More likely, he means the shooting average of an average basketball player in the type of game being observed (pickup game, college, etc). Clearly skill contributes to such a baseline average.<p>With basketball we have a skill that can easily be measured for nearly anyone: we just have them toss a basketball a few dozen times and we have a good gauge of how skillful they are compared to others. But what about, say, a venture capitalist? The game that they are supposed to be skilled at has so much overhead that very few are ever played, and not all those that want to play can (you've got to have a lot of money to even sit at the table). It's quite possible that success as a VC is entirely attributable to luck, with no contribution from skill at all. For these kinds of activities we have no way to generate a meaningful statistical baseline. We can only engage in a thought experiment: if hypothetically the success in question was actually due solely to chance, would the world we see look any different?