Saturday, December 15, 2007

Sit And Goes, ICM and The Size Of Mistakes...

Thinking about one of my favourite poker-related topics today - the size of mistakes.

Nobody plays 'perfect poker' right? The number of unknown variables and individual differences make decision making an inexact science - even in the 'solved' end game of SNGs.

Well, if we accept that everyone makes mistakes then logically it follows that the players making money over time are making less and / or smaller mistakes than their opponents.... Slanksky and Miller referred to this as 'Winning the Battle Of Mistakes' (in relation to cash games).

A competant SNG player needs a good idea of the correct situations and hand strengths required to push or fold at the bubble... without this then money is being leaked. It follows here that your actions are primarily dictated by the calling and pushing ranges of your opponents and the dynamic between the stack sizes at the table (presence of a micro-stack being the 'biggy').

Today I'd like to look at the ranges question. Say something goes wrong with this estimation process... we assign an opponent an incorrect range. Is there a useful way to adapt our play to ensure that any mistake we make due to this is smaller rather than larger??

A couple of examples: Equal stacks and high blinds at the bubble, folded to you in the small blind... you have rags but see your opponent as tight / cautious - lets say you have 8-2 suited and put your opponent on 66+ A10s+ AJo+ to call.... with even stacks of 5000 chips and 300 / 600 blinds you have a clear shove here... it is worth 1.5% of the prize pool!

Ok, so lets imagine you made a mistake!

Instead of 6%(ish) of hands your opponent is actually sitting ready to call you with a healthy 18% of hands!! Thats 3 times as many.... well, your push now gets thin - down to 0.1% of the prize pool - but still has a positive expectation.

Now we can reverse roles, the small blind pushes into you, and you estimate his range incorrectly... you are in the BB with A-10 off suit, seeing your opponent as a competant player you 'know' that he will be pushing 100% of hands in this situation (since in theory at least you 'can not call' without a monster).

You call - your expectation is 1% of the prize pool and that is plently enough to show a profit over time!

But wait, what if you got it wrong... those pushes by the small blind were in fact due to a strong run of cards, instead of an ICM expert knowing that he can push 100% the SB is in fact a fish who would fold 66% of hands here (or complete with them (euch!!)). Note the error is the same size as before (we over-estimated by 2/3rds).... now your error is much bigger... in fact this comes in at -1.3$ of the prize pool in $ev terms.

Kind of a long way of getting there - but here is the thought for today.... if you are going to make a mistake in push / fold poker at the bubble of a SNG then make it a 'pushing' one and not a 'calling' one.... the smaller your mistakes the more money you'll win over time!

GL at those tables, Mark


Anonymous said...

Interesting blog but the bigger mistake is not knowing whether or not you're playing against a fish.If in doubt treat him as a fish and tighten up your pushing and calling range.

Mark said...

Fair point... it is your own responsibility at the end of the day to assess opponents.

When playing 6+ tables, partticularly at the $20 level and below it is a safe bet to assume your opponents are fish until you have evidence to suggest otherwise!

Cheers, Mark