Definition of ICM
ICM stands for "Independent Chip Model". Although we would need a book to talk about ICM in detail, here are some basics. ICM is a topic that is only covered in tournament poker (including sit'n'gos). CMI is calculated with your current chip count in a tournament, the total number of chips in play, the number of players remaining in the tournament and the total money of the paid spots. The result of the MCI calculation will be a cash amount that is the value assigned to your stack at a particular time. When another hand is played, the CMI will have changed.
A critique of the MHI
The ICM is a good tool to determine the value of your stack at any given time in a tournament or sit'n'go. For example, if there are 3 players left in a tournament and the 3 players are of equal strength, we can request an ICM calculation to find out the value of our stack. If all 3 players accept the amount offered, the tournament will be stopped right away and the players will pocket the money that corresponds to the value of their stack. The main criticism of the ICM is that this method of calculation does not take into account the talent of the players. If two players have the same stack, their stacks will have the same value according to the ICM, but in reality, the better player will have a stack that should be more expensive than that of his less qualified rival.