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Fold Equity Function

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02-12-2018 , 04:48 PM

statmanhal

Pooh-Bah

Join Date: Jan 2009 Posts: 4,987

I’m developing an analytical EV model for an all-in or river bet that includes a fold equity function. I believe such a function should have a ‘lazy S’ shape. Low fold equity for small bets, then a fairly rapid rise, leveling off to approach 100% as the bet size increases.

Recognizing that a lot depends on circumstances, here are values that I used for betting against tight, average and loose players. The general equation is

fe = 1 - 1/(1+exp(A*Bet/Pot-4)), where A determines the curve steepness.

Fold Equity Function

Bet/Pot	Tight	Avg.	Loose
0.10	0.03	0.02	0.02
0.30	0.06	0.04	0.04
0.50	0.11	0.08	0.05
0.75	0.25	0.15	0.09
1.00	0.48	0.27	0.15
1.25	0.71	0.44	0.25
1.50	0.86	0.62	0.37
1.75	0.94	0.78	0.51
2.00	0.98	0.88	0.65
3.00	1.00	0.99	0.95

Any comments?

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02-12-2018 , 07:55 PM

AllTheCheese

Carpal \'Tunnel

Join Date: Nov 2007 Posts: 11,898

Just commenting on the output, but it seems way too stationy. If people are folding only ~8% of the time to half pot otr, they are getting value owned. They'd have to be continuing with busted draws.

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02-13-2018 , 12:07 AM

statmanhal

Pooh-Bah

Join Date: Jan 2009 Posts: 4,987

Thanks for the comment.

Any idea of what you would use for fold equity for a half pot river bet with no other info other than an average player ?

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02-13-2018 , 03:20 AM

AllTheCheese

Carpal \'Tunnel

Join Date: Nov 2007 Posts: 11,898

That would be hard for me but possibly easy for others. I stopped playing online poker as a serious pursuit after BF and have since lost all my hand histories. But I would imagine anybody with a million+ tracked hands can give you a good idea how often different sizing takes it down.

My guess for half pot would be ~35%, but I'm not sure. I picked that number because my instinct says it can't be less than 20% or more than 50%.

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02-13-2018 , 11:03 AM

robert_utk

Not From the UK

Join Date: Jan 2005 Posts: 4,822

The complication is the player pool modeling. What stakes? What sites? Super cool and interesting though! Ultimately the equation could be informed by a priori and use classical or modern bayesian methods to generate a perfect bet size for any particular opponent

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