Originally Posted by mcatdog

ICM might have some weaknesses. For example, it assumes that everyone's chance of finishing 1st is proportional to the size of their stack. Sometimes this isn't the case, because one player is likely to have a lot of good situations to keep picking up pots. Meanwhile another player is unlikely to win any pots unless he gets dealt a monster. The situation in taipan's hand is a good example, because the chip leader is probably going to keep pwning the bubble until one of the short stacks calls him, and taipan will keep getting blinded down until that happens (or he gets AA and calls). So, while ICM says the villain has about a 40% chance to win and the hero has about a 30% chance to win, in reality the villain's chances are better than that and taipan's chances are lower.

How does this impact our play in an actual SnG? Well, if we're the big stack and we're pwning a bubble, we should be less likely to call a push from a short stack, because SnGPT is going to under-estimate the equity we'll have if we fold (because it doesn't count the chips we'll pick up by continuing to pwn the bubble). Conversely, if we're the second stack and we're getting pwned, SnGPT is going to over-estimate the equity of a fold. Therefore, we should be calling with more hands than SnGPT says we should call with.

How big of a difference does this make? I don't have a clue, but my feeling is that calling with a hand like 99 (which is borderline according to SnGPT) might be good because of the above considerations, but AK is such a horrible call according to SnGPT that it's probably still bad.

This is something I've been meaning to post for awhile but I just never got around to articulating my thoughts about it.

Originally Posted by Slim Pickens on 2+2

* The error in an ICM-calculated prize pool equity, relative to it's magnitude, gets large when the chip stack involved becomes much smaller than the big blind. This error isn't particularly important to the equity of the big stacks at the table, but it can be important in cases where there are multiple short stacks on the bubble.
* The ICM doesn't account for position, and any attempt to correct it is basically an empirical parameter fit. If position is somehow important in a situation, it won't be reflected in the ICM-calculated prize pool equity. A pair of 2 BB stacks on a 4-handed bubble will probably have different actual values depending on who is going to hit the blinds first.
* If there is a large skill differential, the ICM won't capture it. For example, there are times when a shorter stack can be played much more skillfully than a larger stack because a short stack and a rebuy ticket allows a skilled player to bluff/semi-bluff a lot more hands.