what is icm?

http://www.icmpoker.com/Calculator.aspx

not a very good example imo. Theyve given example where the 4 players each have the same chips. What's that going to show except they all get the same, lol. But thanks anyway for the reply

Sorry, I assumed you would know how to use a calculator.

You input the data yourself, it defaults to the standard bubble structure on a $10 stt, but basically you can alter it to any final table scenario by adjusting the payouts across the top, and the stack sizes in the vertical column.

Its pretty simple and quick to use, which I assume is why a lot of people refer to it when considering chopping in the late stages.

It's also quite handy when looking back over STT hand histories to check you are playing optimally.

ICM is not for chopping ..

I agree glub, as I stated I use it to ensure I'm playing optimal poker on the bubble of my sit and go's.

But surely it would also give players their exact equity at any given stage on the final table of an MTT ?

so chipfire, as youre obviously a good bloke, could you take me through the following hypothetical example - say there are 4 players left, chipstacks 60k, 40k, 25k, 15k, and the 4 prizes left are $10k, $7k, $5k and $3k, and the tournament rule is that $1k has to be set aside to play for in the interest of tournament integrity etc. Can you explain what each player gets under icm please?   

thx if you can be bothered

7640.33
6771.02
5786.03
4802.59

If you had to play for 1k then take roughly 300 off the top 2 stacks and 200 off the bottom two.

in the example given, the chip-chop equity would go:

$8142
$6428
$5143
$4285

be interesting to know how icm compares ....

thx for the reply but could you explain the formula please so i know how the figures are reached?

thx, sorry for being a bore....

LOL, it would make your brain expand to three times its normal size just thinking about it. Which is why you need a calculator or software incorporating it to run it. I believe it a series of mathematical equations which assume all players will play every hand optimally and never make an ev- decision. It's actually more migraine inducing than Nash Equilibrium.

Essentially it assumes that all players are of equal ability and will play every hand optimally. Most importantly it wont take blind sizes into account ( in your above example the blinds could be 20k/40k for instance )simply give you an approximation of what your chipstack is worth in monetary terms at any given stage of a game.

As glub states, it isn't really a tool designed for chopping tournaments, though I can see why some people might want to employ it that way, particularly the weaker players at the table.

ICM is based on the gamblers ruin equation where the probability of winning a tournament is in proportion to the chips held.  The complexity arises from the different payouts for different finishing positions. 

Imagine a tournament where there are two prizes 70% of the fund and 30% of the fund, three players remain with 500 chips, 300 chips and 200 chips.  An ICM model assumes that the players go allin until eliminated and have an equal chance of winning each hand.  So this table gives some idea of this process:

               
1000    0    0    0.33   
200    800    0    0.33   
400    0    600    0.17   
200    200    600       
        1000        0.056
    600    400        0.056
600        400        0.056


stack 1 (500) has won 33% of the time, is in second with various stacks 67% of the time, stack 2 (300) is eliminated 50% of the time on the first allin and a further 5.6% after a second allin (but gets a share of second prize, stack 3 is eliminated 66% of the time and moves on to a second allin the remaining time.

From the above every stack has either been eliminated or is heads-up where the probability of winning is in proportion to their chips. eg stack 1 wins 33% + .2 x 33% + .4 x 17% + .6 x 5.6% and is second .8 x 33% + .6 x 17% + .4 x 5.6%.  So ~ 50% chance of 1st and 39% chance of second, for overall equity of ~47% of the prize fund.

As you can see the simplest possible ICM situation is fairly complicated, so rather than full iteration some models work with approximations.

Thx dave for your v informative reply. It still seems a bit incongruous to me though, that when you think what level of complexity that a mathematical formula can solve, that there isn't a relatively simple formula that can solve what is basically a simple iterative process, even if it involves a square root or logarithmic element within.

Also, if chip-chop formula is perfectly fair, which in my opinion has to be so, I can't see how a method that gives different answers can be anything other than less fair ....

1000    0    0    0.33   
200    800    0    0.33   
400    0    600    0.17   
200    200    600       
        1000        0.056
    600    400        0.056
600        400        0.056

Nice 1.

Dec 20, 2011 -- 7:49PM, toilettennisplayer wrote:

Thx dave for your v informative reply. It still seems a bit incongruous to me though, that when you think what level of complexity that a mathematical formula can solve, that there isn't a relatively simple formula that can solve what is basically a simple iterative process, even if it involves a square root or logarithmic element within.Also, if chip-chop formula is perfectly fair, which in my opinion has to be so, I can't see how a method that gives different answers can be anything other than less fair ....

I'm not sure what chip-chop calc you are referring to.  I do know that some chip equity calcs can result in a value of greater than 1st prize for the a large chipstack, so that to me indicates that it is a flawed method.  ICM models are accurate in terms of providing the true value of a stack at any time.  As far as chopping is concerned, ICM is accurate assuming equal skill and ignoring situations like a 2 big stacks and two micro stacks, one of which is about to be blinded out.

As far as simple formulas are concerned, the actual gamblers ruin equation is quite simple, it is just the number of calculations required to accurately assess each players probability of finishing in a particular place and then the cash value of that.