What is the precise definition of this concept? I know that it is meant to capture the idea that if many ep/mp players fold preflop, that that somehow increases the likelyhood of the lp/blind players having high cards. The argument (if I understand Caro correctly) is that people tend to play high cards, so that when many ep/mp players fold, that indicates that in their hands there are less high cards than average, from which it follows that the rest of the deck can be assumed to be slightly richer in high cards.

The bunching factor will, of course, be most visible when you stipulate that any player will play any high card. But with more realistic assumptions, I'm not sure whether there is any significant (meaning: large enough to be taken into account) change in probabilities.

Surely, when the first eight players fold it is unlikely that any of them had two cards Q or higher. But it is very well possible that four of them had an Ax hand (where x was too weak to make it playable) and the other four had Kx. Some in ep might even have KQ, AJ hands that they mucked.

Of course, this is not a very likely situation, but the main point is that even though people fold, it does not imply that they didn't have a high card.

Is there a rigorous quantitative proof? I would imagine that you would start by stipulating starting hand requirements for all positions and then prove that once the first eight players fold, there is a significant increase of the chance that, say, the BB holds a high card.

Anyone know of a situation in which the bunching factor would really swing a decision the other way?

Just wondering,

Pieter