Trying to become more mathy. Is this the right way to calc EV?

[idrinkmilk]

I only go by feel when I play, but I think that I'd like to improve now. I'd like to start by learning how to calculate EV. Is this the correct way to do it:
[ QUOTE ]

EV = Equity * (Effective Pot - Rake) - Hero Invested


[/ QUOTE ]

And a follow-up question. How should I think before I decision when I have already been forced to make a bet. Like when I am first in from the small blind. Is it like this?
[ QUOTE ]

EV = Equity * (Effective Pot - Rake) - (Hero Invested - Earlier Forced Bets)


[/ QUOTE ]

And in either of the formulas, if EV > 0 then I shouldn't fold.

Is that the way to do it? I feel like a new man [img]/images/graemlins/smile.gif[/img]

[idrinkmilk]

Can both formulas be combined to:
[ QUOTE ]

EV = Equity * (Effective Pot - Rake) - (Current hero bet)


[/ QUOTE ]
where what the hero has already in front of him when the betting gets back to him is only seen as part of the pot.

Is this correct?

[aflaba]

Please people, just drop me a "yay" or "nay" so I know whether I have the basics right

[AaronBrown]

Your formula is wrong for strategic reasons, not mathematical ones. Any calculation of EV that includes past information, like how much you put in the pot or how much of it was forced, has to be wrong. EV is always forward-looking, and always relative.

For example, there's $3,000 in the pot when the river card is dealt. The one other remaining player bets $1,500. If you fold you get nothing. It doesn't matter how much of the $3,000 you contributed. If you like, you could say "if I fold I lose $1,000;" then you subtract $1,000 from the EV of every other option and end up with the same decision. So it's best to make folding your zero point, and compute EV relative to that.

If you call the bet, you get $6,000 times your chance of winning, minus $1,500. If you raise, it's more complicated.

The value of EV as a poker concept is not the precise calculation, since you almost never know your precise chance of winning, nor what the other player will do. The value is it focuses your attention on the future, and the relative value of decisions. Without EV, people worry about what they invested in the past, and the absolute gain and loss on the hand. Both of those are irrelevant, and thinking about them will distract your mind from the important decision.

[pococurante]

Here are two examples.

You have AA preflop. You bet, opponent goes all in for $50, you call. Opponent shows JJ. There is now $100 in the pot, you will win 80% of the time, so your EV is $80.

You have AA. You bet $10, opponent calls. The flop is A85 with two spades. You bet $20, opponent goes all in for $20 more. You are certain that he has a flush draw.

If you call, the pot will be $100 and you'll be 65% to win, so your EV is $65. If you play this hand a million times, your average winnings will be $65.

Ignoring the money that you already put in provides numbers that are useless. In the flush draw situation, your original formula would be (65% x $50) = $37.50. The number 37.5 has nothing to do with anything in this hand.