# How much ChipEV we need for a +EV move on the bubble?

• Bronze
Joined: 08.07.2009
EDIT: another way of framing it is-> How do we translate chipEV into our Tournament EV? (on the bubble)

Ok that is really vague so I'll try and be more precise.

I've been calculating some stuff
blinds = 200/100, ante=50; on the bubble in an STT

We're in the BB, a guy in the SB raises 3x (to 600), the pot is 900. Our relative stacks are 3700. Therefore our stack to pot ratio (SPR) in this situ is 4.

When I wondered when a shove in this situation is profitable, I've come up with things like:

SB raises 47% but raise/calls only the top 5% of hands
Shove has massively positive chipEV when SPR=4 (it's positive up until SPR=20, where it gets closer to break-even)

if a guy raises 47% of hands but (reacting to our shove) calls only the top 5%, we can profitably (in terms of chipEV) shove any two. He will only call us 1 out of 9 times (the other 8 times we win 900 immediately), and even if we get called we have some equity, so chipEV in this spot [I'll skip the calculations] is massively positive up until SPR=20 where it starts to get break-even.

Guy raising 24% but calling only the top 5% of hands
Shove has positive chipEV when SPR=4 (it is positive until SPR goes to 12 - then it starts to be a close to break-even move)

if a guy raises 24% of hands but (reacting to our shove) calls only the top 5%, we can profitably (in terms of chipEV) shove any two. He will call us 1 out of 5 times (the other 4 times we win 900 immidiately), and even if we get called we have some equity, so chipEV in this spot [I'll skip the calculations] is massively positive up until SPR~12.

Bottom Line
The question I'm asking is how does the fact that we're on the Bubble affect that decision? We're risk averse, so we don't want to get into borderline spots (where chipEV is slightly positive). How much chipEV do we need in this spot to be able to say, ok, I've considered Bubble Risk Aversion, but the benefit from the shove is big enough for it to be a generally +EV move?

Cheers,
Matt
• 7 replies
• Bronze
Joined: 01.06.2006
Basically the procedure is allways the same:

1) you use ICM to give your chips a \$ Value.
Then you consider the different situations:

a) You fold = (if it has been an openfold) the \$ Value of your chips remains unchanged.
b) You call (or push and get called) and win = do the math for the probability that you will win.
b#2) You call (or push and get called) and lose = do the math for the probability that you lose.
b+b#2 = do the math against and reevaluate the \$ value.

Now; what is so special about the bubble? If you knock out someone on the bubble you are in the money. If you double up a short stack vs a medium/big stack you still are on the bubble (the bubble does not burst). Most of the time there will be a short stack on the bubble which is why all but the big stack must be much more risk averse.

On another note; pzhon often does mention his tool (icmexplorer.com) which shall allow you to figure out the bubble factor. Maybe this gives you a better feeling. I have never used it, so I cannot really comment about it.

Long story short: opposite to the first hand in a 9 man SNG where you need like 55% Equity to go broke (and therefore most likely will have to fold QQ) there is no mathematical rule for the bubble play.

Howsoever, there are some guidelines:

- As big stack you can push very wide vs medium stacks if there is a short stack, because doubleing up against you does not double their value.
- The big stack will get called looser from a sole short stack (because he needs to double up). Then again, the short stack has a bigger interest in doubleing up against a medium stack, since this does increase his chip value way better (he now probably is a medium stack and there is a new short stack, except for 4 medium stacks).
- As a medium stack you have more interest takeing out the short stack (because this makes the bubble burst) instead of doubleing up against the big stack (which puts your tournament life in danger).
• Bronze
Joined: 08.07.2009
Thanks for the reply that's a lot of effort you put in there.

I don't get this bit:
Originally posted by Th0m4sBC
Basically the procedure is allways the same:

1) you use ICM to give your chips a \$ Value.
How?
• Bronze
Joined: 01.06.2006
http://www.pokerstrategy.com/strategy/sng/175/1/

/e: you also might use tools like holdemresources.net
• Bronze
Joined: 08.07.2009
Originally posted by Th0m4sBC
http://www.pokerstrategy.com/strategy/sng/175/1/

/e: you also might use tools like holdemresources.net
I've read the article before but it isn't of much help regarding calculation of the percentages:

"(...)If this procedure is repeated many times, we can get the probability of each player obtaining a particular place by keeping track of how many times they win it."

and also had a look at HE Resources - ICM section is not yet ready, what I really need is an ICM calculator, which I've found here: http://www.icmpoker.com/Calculator.aspx

Thanks mate!!
Matt
• Bronze
Joined: 01.06.2006
Good to hear that you found a tool to do the math. !
• Bronze
Joined: 03.09.2008
use icmexplorer, it gives you the you chip equity and the equity needed after ICM, using a value called the risk premium.

Work out and remember risk premiums for different spots and you'll know how much more equity you need in different spots because of ICM considerations, very quickly
• Bronze
Joined: 08.07.2009
cheers guys, I started to use ICM Explorer to look at different spots, will soon develop a better understanding which in turn will hopefully get translated into ROI!!

Thanks again Th0m4sBC and elhh82