PDA

View Full Version : Equity miscaluation?



Cafeman31
02-03-2011, 03:17 PM
I think there might be a small logic problem when HM calculates Equity % and I was all in preflop against 2 others who didn't go all in until the flop. Example:-

No-Limit Hold'em, $0.02 BB (8 handed) - Hold'em Manager (http://poker-tools.flopturnriver.com/Hand-Converter.php) Converter Tool from FlopTurnRiver.com (http://www.flopturnriver.com)

Cafeman31 (SB) ($2.31)
BB ($2)
UTG ($1.76)
UTG+1 ($4.28)
MP1 ($2)
MP2 ($4.92)
CO ($2.21)
Button ($4.11)

Preflop: Cafeman31 is SB with Khttp://www.flopturnriver.com/pokerforum/images/smilies/diamond.gif, Khttp://www.flopturnriver.com/pokerforum/images/smilies/spade.gif
1 fold, UTG+1 bets $0.60, 1 fold, MP2 raises $1.34, 2 folds, Cafeman31 raises $2.30 (All-In), 1 fold, UTG+1 calls $1.71, MP2 calls $0.97

Flop: ($6.97) 5http://www.flopturnriver.com/pokerforum/images/smilies/diamond.gif, Khttp://www.flopturnriver.com/pokerforum/images/smilies/heart.gif, Qhttp://www.flopturnriver.com/pokerforum/images/smilies/club.gif (3 players, 1 all-in)
UTG+1 bets $1.97 (All-In), MP2 calls $1.97

Turn: ($10.91) 7http://www.flopturnriver.com/pokerforum/images/smilies/heart.gif (3 players, 2 all-in)

River: ($10.91) 10http://www.flopturnriver.com/pokerforum/images/smilies/club.gif (3 players, 2 all-in)

Total pot: $10.91

UTG+1 had 78c and MP2 had AsAc.

Lucky me! :)

BUT, the Equity % is showing up as 83.7% in HM for this hand. However, when I went all in (preflop) it's more like 17% (using pokerstove). 87% is correct from the flop however.

My point being, surely if I went all in preflop, the equity I had in the hand should be calculated from there and not from the flop.

What do you reckon?

Patvs
02-03-2011, 07:26 PM
Allin preflop AA vs KK vs 78s you'd only have 17% equity.

But your hand is a unique situation, since you were allin preflop, but the betting between two opponents continued on a later street.

For this reason, HoldemManager calculates you as being allin on the flop when you had already hit your set.
That may sound illogical. But the reason is, often one opponent makes the other opponent to fold. When that happens, no one actually knows what the holecards are of that opponent. (he may have had the best hand preflop)

Classic example:
Shortstack goes allin preflop with a 22. JJ calls. ATs calls.
Flop comes AK2. ATs bets. JJ folds.
22 wins the hand.


So HoldemManager ignores the preflop allin in any such situation. Otherwise it would lead to biased results if it would only calculate preflop EV when all the holecards are known, but would ignore it when one of the opponents folds.

Cafeman31
02-04-2011, 05:03 AM
So HoldemManager ignores the preflop allin in any such situation. Otherwise it would lead to biased results

I think I understand what you're saying, but surely it's just swapping one kind of bias for another kind. I mean, surely we can't argue that my equity in the pot when I went all in was as much as HEM seems to be suggesting. I mean, now I know how it works it out I can take that into account on a hand by hand basis, but when I look at the graph and include EV, imo it's giving me a false impression. I suppose this stuff averages out over many hands to be accurate though... thanks for your answer.

Patvs
02-04-2011, 01:43 PM
The EV "problem":
A: If a player has 0 outs, or
B: the allin situation takes place on the river there is NO EV DIFFERENCE.
C: If a shortstack goes allin preflop, and is called by two bigstacks. And the two bigstacks continue to bet on the flop, turn or river, this situation is treated as situation B. (EV = 0)
Fozzy: "You can't calculate all-in equity if you don't know the hands you are up against."
D: If you commit 99% of your stack with the best hand, but your last 1% goes allin with the worst hand, the $EV Difference will be calculated by your entire stack.

Why "EV by street" (which people who often see situation D want) is a bad thing:

Example:
- you have AA, you raise to 80% of your stack, donkey calls, flop comes K83 rainbow.
- you then go all-in, no matter the flop, because you're committed.
- out of 100 times, 88 times donkey folds.
- 12 times donkeys calls with a set (33/88/KK).
What shall EV by street wrongly do? It shall do no computations for the 88 times where donkey folded--> "no more calculation".
What shall EV by street do the 12 times where donkey calls with a set? "Show that donkey sucked out and that you got unlucky".

So although you ran obviously really good by having donkey folding 88 times out of 100. EV by street focuses on the 12 times where donkey hit his set and tells that you're running below EV.
This is a well-known gambler fallacy. And this is why "EV by street" is biased.

Note: Tristanblue writes "it's precisely because EV by street does nothing to your adjusted-graph on these cases where the opponent folded that it is wrong".

But what if your opponent never folds? Suppose there are two players A and B.
Player A has AA, B has KK. (both have $100 stacks). They commit half their stack preflop and the flop comes AK6. Player B (KK has 1 "out") to win the hand.
If I would play this hand I would always make sure I'm allin on the turn.
However Player X always commits the rest of his stack on the flop and turn *except for one dollar*. And he commits on the river.
Of course, 4% of the time, the rivercard is the case King. Player X's EV Diff is always 0. (because he goes allin on the river)
My EV Diff (I go allin on the turn) is -$4 (96 out of 100 times) and +$96 (4 out of 100 times)
So our EV graph actually looks exactly the same after 100 of these hands.
(-4 * 96 + 96 * 4 = also equals 0!) So the EV outcome (in the long-term) is the same no matter how you play the hand. And no matter which type of EV calculation you use.


--

Your hand is similar to the last example.
Both EV calculations will have the same long-term result.
But EV by street isn't possible (since you often just don't get to see all the players holecards) So we use All-in EV instead.

You're right that gives a false impression for this one hand (for example in the EV graph), but the long-term results are accurate.

Alternative (EV by street), the results for this one hand would show the correct EV. But for many hands it wouldn't be able to calculate anything, leading to false long-term results.

Cafeman31
02-04-2011, 02:09 PM
Thanks for taking the time to give that more detailed explanation; I think I'm now up to speed.