I have been watching some of the WSOP-Europe. One of the announcers has the habit of saying a player "picks up more equity" when the turn card gives the player more outs.
For example, suppose Hero gets it all-in with Ts 8s vs Villain's Ah Ad on a Js 5c 2s flop (this example is purely made up and may not make any sense poker-wise).
Then the graphics on the top of the screen will show that Hero has 9 immediate outs (the 9 remaining spades). In terms of equity, Hero has around 38% equity on the flop due to back-door draws (and the possibility of losing with a flush to a full house).
Now suppose the 7c hits the turn. Hero now has 12 outs (9 remaining spades plus 3 non-spade nines). The esteemed commentator gushes that Hero has picked up more equity! Of course, the graphics on the screen show that in fact Hero's equity has fallen to 27%.
The "negative effect" of missing on the turn is greater than the "positive effect" of Hero picking up a few more additional outs.
Okay, besides pointing out the daffy commentator, what's the purpose of this thread? I thought I would try to derive the formula for how many additional outs a "missed" turn would have to give Hero for Hero's equity to actually increase.
I simplified the derivation as follows. I assumed that Hero has X outs on the flop (ignoring any back-door draws). I then assumed that Hero misses the turn but picks up an additional Z outs. Then I solved for Z in terms of X in order for Hero's equity to increase.
If I plowed through the algebra correctly, I find that:
Z > X * (44-X) / 45
Here's a table of these values.
Outs on Flop | Reqd Addl Outs on Turn for Equity to Increase | |
---|
7 | 5.76 | |
8 | 6.40 | |
9 | 7.00 | |
10 | 7.56 | |
11 | 8.07 | |
12 | 8.53 | |
13 | 8.96 | |
14 | 9.33 | |
15 | 9.67 | |
You can see that it requires a hell of a lot of additional outs to make up for missing on the turn. Poker experts can weigh in on this, but I would hazard a guess to say that it is a rare occurrence.
By the way, the formula above looks like it might have a "nice" explanation. I will write it again here:
Z > X * (44-X) / 45
Of course in a heads-up situation, the turn comes from a virtual deck of 45 cards and the river comes from a virtual deck of 44 cards. Remember Hero has X outs on the flop.
Does anyone have any thoughts on this formula or anything else related to this topic??
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Last edited by whosnext; 10-29-2019 at 02:59 PM.