Wasted bet on the river?

[Nate tha' Great]

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Once in a great while you can isolate against SB with a draw and win unimproved when neither of you makes anything.

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SB will bet betting out with a draw here pretty often. When that's what SB does, raising is far and away the best play. If the players behind him want to cold call with a pair or something, that's fine because Hero has a shitload of equity against their hand. If they want to fold middle pair, that's even better, since Hero has radically increased his chance of winning the hand.

If SB has a better hand then Hero, raising is at worst a tiny mistake:

1) There's no guarantee that the players were going to overcall to begin with.
2) There's no guarantee that they *aren't* going to cold call two bets, and Hero gains immediate equity on the raise once one of them does.
3) If all of them fold, the raise likely buys the Hero a free card.
4) There is a small but material importance to the possibility of eliminating hands like J9, A9 or KT.

In other words, I think the EV calc looks something like this:

Case A. SB is betting out with a draw. Raising is hugely advantageous, possibly +1.0 BB.

Case B. SB is betting out with a made hand. Raising is slightly disadvantageous, possibly -0.1 BB.

A raise is in order.

[J.R.]

Fot whatever its worth I think that the type of player who is sophisticated enough to jam a draw is opting for the check-raise here, and I think this flop bet is most often a made hand looking for the pfr to raise and offer protection. Say what you will about party idiots, but this is my experience.

[StellarWind]

These raise-to-isolate/call-for-overcalls decisions with flush draws that include either ace-high or a small pair seem to come up a lot. I need to sit down sometime and do a complete EV computation for a couple of them. I think it would be very educational.

For now I've made a small start at considering the situation.

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2) There's no guarantee that they *aren't* going to cold call two bets, and Hero gains immediate equity on the raise once one of them does.

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This is not always true. Suppose we have a 40% chance of winning the hand and SB will always call the raise.

1. If both the players behind us coldcall we gain (4 * 40%) - 1 = 0.6 SB.

2. If one player coldcalls and one player was never calling we gain (3 * 40%) - 1 = 0.2 SB

3. If one player coldcalls and one player is forced out we lose (2 * 40%) - 1 = -0.2 SB

4. If one player was never calling and one is knocked out we lose (1 * 40%) - 1 = -0.6 SB.

5. If we knock out both overcallers we lose (0 * 40%) - 1 = -1.0 SB

6. If no one was ever calling we lose (2 * 40%) - 1 = -0.2 SB

In each case the computation is gain of raising compared to just calling. The overcalls we lose when we force players out count as negative bets. Once we knock a single player out the direct EV from the raise is always negative.

Knocking players out also reduces your implied odds when you make your flush, reduces the number of players available to share the drawing cost on the turn, and exposes you to a possible -EV 3-bet.

It's pretty obvious to me that raising a better hand is quite a bit more than a tiny mistake. I'm not ready to believe -0.1 BB or anything like it.

On course successfully isolating a drawing hand is a coup. About 1/3 of the time you will win the hand because of this. [The rest of the time you would have won anyway by making your hand or he makes at least a pair.] That gives you an extra 1/3 claim on a final pot worth about 7 BB. That's more than 2 BB.

It's interesting that it is a considerably bigger achievement to trap a dominated flush draw than a straight draw. The straight draw has more independent outs and a much better chance of winning when you don't improve.

[tolbiny]

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Suppose we have a 40% chance of winning the hand and SB will always call the raise.

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We hit the nut flush around 40% of the time, if we count our ace outs as pruly clean we hit an Ace/fulsh around 52.5% of the time.
Natually sometimes our A's will lose, and fairly rarely our flush will lose, but our J's are an out sometimes, and a backdoor straight sometimes, and our A high unimproved will win sometime meaning that i think your 40% estimate is far to low.
Also note that the fewer people who call the flop the more likely it is that our A/J/A high outs are good on the river.

If you take your estimate to 45% We win

1. If both the players behind us coldcall we gain (4 * 45%) - 1 = 0.8 SB

2. If one player coldcalls and one player was never calling we gain (3 * 45%) - 1 = 0.35 SB

3. If one player coldcalls and one player is forced out we lose (2 * 45%) - 1 = -0.1 SB

4. If one player was never calling and one is knocked out we lose (1 * 45%) - 1 = -0.55 SB.

5. If we knock out both overcallers we lose (0 * 45%) - 1 = -1.0 SB

6. If no one was ever calling we lose (2 * 45%) - 1 = -0.1 SB


But i really think we have closer to 50% equity here which would make Situation
1. 1sb gain
2. 0.5 sb gain
3. 0 sb neautral decision
4. -0.5 sb loss
5. -1.0 sb loss
6. 0.0 neautral decision.

Which makes it a good case for raiseing here.

[StellarWind]

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We hit the nut flush around 40% of the time, if we count our ace outs as pruly clean we hit an Ace/fulsh around 52.5% of the time.

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I don't know where your odds come from. You only make a flush 35% of the time. Making a pair of aces is only about 10% more. For a rough EV calculation I think a 40% chance of winning is fine.

Every player should know that 14 is the smallest number of outs that is favored to make by the river. We only have 12.

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Which makes it a good case for raiseing here.

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Raising:

1. Is -EV on the flop action including possible 3-bets by hands you need a flush to beat.

2. Significantly increases your chance of winning assuming SB often bets his good draws.

3. Greatly decreases the amount of money that others will put in the pot on the turn and river. This is due both to immediately knocking players out and frightening the ones that remain. Your flushes and even your pairs of aces will drag smaller pots.

4. Will buy you an occasional free card.

Drawing overall conclusions from EV computations that neglect #3 is unsound.