Well, this week off has been really useful in terms of learning about poker. One of the leaks that Leak Buster picked up on was playing flush draws passively on the turn. I'm pretty sure I did the implied odds calculations a long time ago, but for some reason over the two or three years since I've picked up the habit of playing flush draws passively on the turn "hoping to hit and WIN" - a very fishy mentality. So I went back over the maths on a piece of paper and it really has hit home how much implied odds are needed to play a flush draw passively on the turn just in the hope of hitting it on the river.
Implied Odds on The Turn
I shan't go over too many calculations (indeed I may have got some of this wrong, please correct if so) but the EV of your call is:
EV = P(x)*(current pot + future profit) - (1 - P(x))*(bet to call)
[P(x) is the probability we win on the river or in other words the equity of our draw in this case]
If we set EV = 0 and rearrange for future profit we get:
future profit = {(1 - P(x))*(bet to call) - P(x)*(current pot)}/P(x)
This equation tells us what the break even future profit should be in order to justify a call.
Right you don't need to know that formula I just wanted to demonstrate where I'm getting my results from. I have used a couple of examples in pokerazor and I think my calculations are pretty close but again, my maths isn't that good so correct me if you find any errors.
If we must call a half pot sized bet on the turn and assuming we have 20% equity with our flush draw then:
future profit = {0.8*(0.5) - 0.2}/0.2 = 1
That is, we need to win - on average - the current pot size in future profit to justify calling using the immediate odds.
Example
We have AhKd on Qh7h4h2d and we know for certain (somehow) that villain has a set from the flop. Our equity according to stove is 0.18 but let's assume it's 0.2 which is close enough. Villain bets $7.5 into a pot of $15 and has $7.5 remaining. This is a situation where I've called in the past but calling is not correct because we can only win $7.5 on the river. Villain would need $15 behind and always call it off when our draw comes in to make this a break even turn call. I can think of some situations where we might call in this instance (assuming villain has $15+ behind on the river) but we'd need to be sure he is calling almost all of the time when our draw gets there.
If we must call a pot sized bet on the turn:
future profit = {0.8 - 0.2}/0.2 = 3
So now, we need to win 3 times the current pot size on average to make calling correct. I can't ever see a situation where this is going to be close to being true. Thinking of our example before, when villain bets $15 into the $15 turn pot we need him to pay us off on average $45 on the river which would be a pot sized river bet. We'd have to be damn sure he has a strong hand and also that he never folds on scary boards to even merely break even in this spot, and to profit we'd need to over bet and always get called. Sounds pretty thin, huh?
So I'm going to try really hard from now on to make these hands semi bluffs rather than passive draws. If I have the betting initiative then I can at least double barrel with these hands; if I meet aggression at any point after the flop then the best play is most often going to be to fold.
Most unmade hands on the turn are going to have pretty shitty equity so it's probably very sensible at the micro limits to be turn barreling in just a few good situations and folding the rest of the time. I currently c-bet around 65% of the time and turn barrel 45%. These numbers actually seem pretty reasonable to me so I don't think I'm far off. Hopefully my improved play with draws will get me an extra buy-in or two per 100k hands. GL
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