ICM (Independent Chip Model)
Also called Independent Chip Model
ICM (Independent Chip Model) is a math model that estimates how much of a tournament's prize pool your chip stack is really worth, not just its chip count.
In a tournament, your chips don't convert to prize money one-for-one. This model takes everyone's stack sizes and the payout structure, then estimates each player's share of the prize pool by assuming your chance of finishing first equals the share of total chips you hold (lower-place odds are worked out from there). The big takeaway: chips you might lose are usually worth more than the chips you'd gain, so busting out costs you more than doubling up earns you.
It matters most when real money rides on simply surviving, like on the bubble (the spot just before players start getting paid) or near pay jumps at a final table. In those moments it can be correct to fold a hand you'd happily play in a cash game, because going broke is so costly. Big stacks can bully, since they risk chips without risking elimination, and medium stacks feel the most pressure, since they have a lot to lose by busting before the short stacks do.
As a beginner, you don't need to do the math at the table. Just remember the instinct: late in a tournament near the money, survival has extra value, so tighten up on close spots where losing would knock you out. Early on, when payouts are far away, this effect is small and you can play closer to normal.
Example
You're on the bubble with A-J offsuit and the chip leader, who covers you, shoves all-in. In a cash game this is often a fine call, but with an even shorter stack at the table about to bust and lock you a pay jump, the model says fold: busting now throws away that near-guaranteed payout, while calling and losing earns you nothing.