Calculating +EV/-EV calls

[nincomepoop]

Let's say we ignore poker for a moment, and only base our call off percentages.

River card hits, pot is $18, villain bets $8, making the pot $26. If we call, the pot is laying us (26:8)=3.25:1. Meaning we need to be ahead of villain ~30% of the time to make this call +EV. (8/26=.307). Am I on the right track here?

[Copernicus]

close...its 8/34, or a little less than 25% of the time.

Make it a bit simpler and say odds are exactly 24:8 (ie 3:1). Then in 24 games you lose $1, but in 8 games you win $3, so you are breakeven in 32 games, not 24 as you were proposing when you say you need about 30% chance.

BTW, dont feel bad, I forget who it was but one of the young pros who had a high (winning?) WPT finish in 2004 was making the same mistake you were (even after his tourney wins), and admitted it in a blog.

[jackaaron]

[ QUOTE ]
close...its 8/34, or a little less than 25% of the time.

Make it a bit simpler and say odds are exactly 24:8 (ie 3:1). Then in 24 games you lose $1, but in 8 games you win $3, so you are breakeven in 32 games, not 24 as you were proposing when you say you need about 30% chance.

BTW, dont feel bad, I forget who it was but one of the young pros who had a high (winning?) WPT finish in 2004 was making the same mistake you were (even after his tourney wins), and admitted it in a blog.

[/ QUOTE ]

This is a different way of looking at it? I'm obviously missing something.

For example, when I have a draw to a flush, and the pot has t100, and it's t20 for me to call, obviously this is +EV.

However, the approach suggested above is different.

Is this an example of what you're talking about?

I have AK, and the flop is K 4 7 all of different suits.

Maybe this line of thinking in this post is 'different' than the way I'm expressing it. When the OP says, "Meaning we need to be ahead of villain ~30% of the time to make this call +EV. (8/26=.307). Am I on the right track here?" Maybe he's not talking about drawing to a better hand, and so I'm misunderstanding him.

For example, let's say he has AK, and the flop is K 4 6 all of different suits.

Villian bets 150, and the pot is now at 300...are you and the OP suggesting that I don't call the 150 unless I think I'm ahead 66 percent of the time?

[AaronBrown]

The original question is speaking about uncertainty about what the other player has, rather than uncertainty about what card will be dealt. The math for EV is the same (although the full analysis is quite different). If 9 of the 46 remaining cards win for me, or if I judge there's a 9/46 chance that the other player's hand is worse than mine, the EV calculation is the same.

In your example, if you call a $150 bet with $300 in the pot (i.e. the pot will be $450 after you call), you are +EV if your chance of winning is greater than 1 in 3. You win $300 once and lose $150 twice to break event. But the decision to fold, call or raise depends on more than just EV.

[absoludicrous]

Good explanation Mr. Brown.

Essentially what OP is saying is that if he's being asked to call a bet in which the pot is laying him $450:150 on his call, or 3:1. He has to make the winning hand at least 33% of the time to break even. If you can't make that winning hand 33% of the time to break even, it's not a +EV call.

For example,

You have a 9 out flush draw. On the turn there is $300 in the pot, your opponent bets $150, making the pot $450. So if you call you're getting 450:150 on your call. In other words 3:1. There are 9 possible out of the 46 remaining cards. So 9/46 = 20%. We'll make the flush 20% of the time on the river, from a pot odds point of view, we need to improve at least 33% of the time in order to make this a +EV call. We only make the flush about 20% of the time so the call is -EV.