I was reading and participating in a thread that got kind of long so I stopped reading things. But I just wanted to clarify some things about EV that some people may be misunderstanding.
EV - Expected Value
Expected value is a simple math function that is used in poker to determine the value of making a certain given action. In the world of poker, this is usually a bet, call, or fold. (Not always)
The two most important forms of EV in SnG Tournament poker are chip EV (cEV) and money EV ($EV).
cEV - Chip EV
Chip EV measures how many chips you will win or lose, on average, if you make a certain play. We use this as SnG players to make most of our decision during the game. Why? Because making a correct Chip EV decision will usually be +$EV. But, not always!
$EV - Money EV
Money EV is a little more complicated. Money $EV is calculated using a more complicated formula (which I have no idea how it works) called Independant Chip Modeling. Independant Chip Modeling (ICM) is used when the chips we are playing with are not real money. In that case we assign every chip it's own real money value, according to how many players are remaining, the distribution of the stack sizes, and the way the tournament prizepool is awarded.
How can a +cEV decision be -$EV, or vice versa?
This happens because of the uniqueness of the tournament format. Only certain places get paid and in certain circumstances it becomes wrong to make +cEV or -cEV plays because of the way the tournament is structured.
Taking or passing on +EV (cEV or $EV) plays.
We almost always want to take a +EV opportunity when we have one, and that is obvious. But when should we avoid +EV situations? Well, as I discussed earlier, it is easy to find situations where it is correct to pass up a +cEV decision. Usually this is the case because due to the structures of the tournament, making that play is actually -$EV at the same time that it is +cEV. We are all about the $EV here.
Is it ever correct to pass up a +EV play?
Sometimes it is correct to sacrifice an immediate +$EV action. That happens when one could make a +$EV play that eliminates or alters one or more variables at a poker table that had been allowing one to exploit his table for +$EV. In this case you are sacrificing future $EV for immediate $EV, and sometimes it could be correct to not make the play because you plan on making more in future $EV than you would in immediate $EV.
Other things..
Sometimes the only thing you can do is make a -EV decision. In this case, you need to choose the decision which offers a less -EV. (This happens often when you are in the Big Blind or in Early Position with an extremely short stack).
You can never be forced to make a +EV decision in poker. There is always a neutral EV and/or a -EV decision available to you.
There can be more than one and even many +EV or -EV plays to select from when choosing what your action is.
