Saturday, May 2, 2009

ICM and SPR

Thanks to a separate comment by Laff, I'm very aware that I don't even understand the implications of Independent Chip Modeling or Stack to Pot Ratios, so at least there is lots of room for improvement.

If anyone out there (read, either of you) know of any good links for in depth explanations of the implications of these concepts, please feel free to leave the links as comments for me and anyone else that may be bored enough to stumble across this post in the future. Maybe my kids, eh?

5 comments:

James P McAteer said...

TBH I thought ICM had more relevance to SNGs. I think its too complicated to work out manually (i.e. in your head).

microstakes bankroll builder said...

icm, while primarly developed for sngos, is a concept that is also true for tournies, ESPECIALLY in the later stages, and thats why i mentioned it in your post where you had a decision with a9.

here are 2 examples:

a typical example of ICM v simple pot odds is ak v 22.

if you sit at a table with 9 others, all with the same chips, and you decide to go all in with your ak after the 22 raise, and the 22 calls, then it is a +EV decision from a chip point of view for both player, if you include the money already in the centre, but a -EV decision from a $$$ point of view.

the reason being that if you calculate everyones share of the $$ before the hand starts it is exactly 1/9 of the prize pool (assuming you are all equally skilled)

but if you win the flip, you do not get all the losers 1/9th, as that is distributed between you and the remaining 7 players, unevenly.

(note all this money would be shipped to you directly with the other 7 getting nothing if it was a cash game)

the other reason you should consider $EV over tEV is if you think you are a better player and have an edge in agression and thus $EV. an example is if you have a decent stack, and there is plenty of play left in the blind structure, and you have AK utg and raise. A player with a similar stack to yours(TAG or LAG is irrelevant in this instance) in the BB raises to commit half his stack.
basically your choice is all in or fold. Now many just auto shove but this is where $EV (your future share of the prize pool) needs to be considered. you are basically putting your tournie onto a coinflip (% of time he has Ax and is crushed is negated by % of time he has AA-KK and you are crushed). ICM does a mathmatical calculation where it takes that 50% and it puts that into your current share of the prize pool, taking account of you and everyone elses chips. (note this is not relevant if you will not be crippled if you lose, and was relevant to your a9 situation as it did indeed effect you later on i think)

it sounds complicated but its not once you get our head round it. its the fundamental difference between tournaments and ring games.

finally some pros will always go for the coinflips regardless of what i have said as they want to build monster stacks and are happy to bust trying. because they know once they have the moster stack it is v likely they are going to get at least final table, prob more. gus hansen is one. others play the opposite helmuth, matasow, smallball, they call it i think.

for your a9, there is no way you can do the ICM calc, you need a peice of paper and pen, but you can just use a few rules of thumb.
1. can i fold this and play on happily, or are the blinds creeping up and stack is dwindling
2. am i out of my depth, and i am happy for a coinflip/gamble for my tournie
3. can i steal or can i only play premium hands
note that pot odds are not really the issue.
if ever you watch EPT antonio esfandiari did exactly this thought process as he was within site of the final table last year at monte carlo and ended up folding ak. none of the books get into this topic, but it is fundamental. there are not many people who have mentioned ICM in a MTT format, but for what its worth, it really helped me (i started off playing small buyin sngs and mtts, succesfully, but after but wanted to play cash poker, as there is more skill, and thus more to learn). i am sure i havnt explained it all properly but i think i have the general points.

phew...... what a rant. i hope that helps

parttimebonuschaser said...

i think from memory sitngoplanet has some articles on ICM as well. Probably some tools too

TiocfaidhArLa said...

wow ... thx guys for all the feedback on ICM. It is something that I will think over and not get too scientific with live.

Your rules of thumb are very valid and intuitive and with respect to the A9, your spot on ...

1. could i have folded and played happily - Yes
2. out of my depth and happy with a coinflip - No
3. can i steal - Yes

In fact, my mistake in the PLO with KK99ss could have been avoided had I gone through this thought process. AQs you say, cash games, no problem, get it all in there.

I'm off to check out sitngoplanet et al. Thanks all.

The blindman said...

I wouldn't worry too much about ICM until you get close to the bubble. That is when your $EV and tEV can diverge markedly.

In extreme situations (e.g a qualifier with perfectly flat payout), it can become correct to laydown AA preflop.

Regarding your Q high flush hand, I think I probably would have called in that situation. The overbet looks too much like a bluff - Kc or Ac is going to make small value bets 90% of the time there (especially with 1 street still to come).

ICM is not enough of a factor to make me change my mind.