Calculating EV?

[dacium]

I have a problem with my program (again) ;-P

It can do both mathematically exact calculations and simulations. The problem is I am not getting EV= -0.5% but i am get EV= -2.5%.

I am using following rules:
6 Deck, DAS, Split once only, One card to split aces, Dealer stand on S17, 3:2 Blackjack. Loose original bets only to a blackjack. No surrender. Double 9-11 hard only.

I am not sure I am computing EV correctly, how exactually is it calculated?

I am doing: EV = (won - lost) / (total bets made)

My program is doing:
((1.5*BJ) + (2*DoubleWin) + Win)) - ((2*DoubleLoss) + (Loss) + (Bust))
divided by:
BJ + (2*DoubleWin) + Win + (2*DoubleLoss) + (Loss) + (Bust) + (Push) + (DoublePush)

I can't see where the error is. My basic stategy that the program is following is:
Double 11 vs 10 or below
Double 10 vs 9 or below
Double 9 vs 6 - 3
Hit hard 16 or below against 7 or above
Hit hard 12 against 2 or 3
Hit soft 17 and below, hit soft 18 against 9 10 A

Splits:
2 against 7 or below
3 against 7 or below
4 against 5 or 6 only
5's never
6 against 6 or below
7 against 7 or below
8 always
9 against all except Ace Ten Seven
Tens never
Aces always

I was expecting these rules to be about 0.5% to 0.6% but im getting about 2.5%

 

[dacium]

I fixed one mistake, I am now getting a EV of -1.19%

 

[dacium]

Is this value likely the correct one? Like when they say 0.5% house edge, do they really mean 49.5% of the time you get your money back, so the actuall EV on $1 is only 99% not 99.5%?

So this 1.1% is probably correct in that you will get back 98.9% of the money you bet?

 

[Sonny]

My program is doing:
((1.5*BJ) + (2*DoubleWin) + Win)) - ((2*DoubleLoss) + (Loss) + (Bust))
divided by:
BJ + (2*DoubleWin) + Win + (2*DoubleLoss) + (Loss) + (Bust) + (Push) + (DoublePush)

Are you looking for the IBA (Initial Bet Advantage) or TBA (Total Bet Advantage)? The formula above is for TBA, but most EV calculations use the IBA which would be:

(Win-Loss) / Number of Hands Played

So just switch your program to:

divided by:
BJ + DoubleWin + Win + DoubleLoss + Loss + Bust + Push + DoublePush

Also, make sure that you are not "double counting" any hands. Does a blackjack increment the "BJ" and "Win" variables? Does a player bust increment both the "Bust" and "Loss" variable?

Alternatively, if you know the BASIC programming language you can hack this open source program:

http://www.blackjackforumonline.com/content/SimSimp_Beta.htm

The new version uses XBasic but I still have a copy of the old "QBasic" version if anyone needs it.

-Sonny-

 

[MGP]

I have a problem with my program (again) ;-P

It can do both mathematically exact calculations and simulations. The problem is I am not getting EV= -0.5% but i am get EV= -2.5%.

The CD/CDZ- EV is -0.551996675529408%
The CD/CDP EV, which I assume is what you're calculating is the same with these rules.

The former uses the same strategy for a given hand pre- and post-split, while the latter determines the CD strategy post split based on the removal of the paircards.

I am not sure I am computing EV correctly, how exactually is it calculated?

I am doing: EV = (won - lost) / (total bets made)

There isn't a right or wrong way to calculate it but the convention is to use the net gain based on the initial bet.

So for regular hit/stand we simply do (win-lose). For doubles you do 2x(win-lose). You shouldn't include pushes in the EV calculation because the EV for a push is 0. I initially did that too btw.

Good luck and enjoy

I've been working on my program for way too long now but finally see an end in sight.

MGP

 

[dacium]

Taking out pushes just makes the EV worse, as you loose more money on an average hand, because there are less hands.

Does that CD/CDZ value mean that If I bet $1 i expect 99.5c back? Or does that mean the house edge is 50% + 0.5%, which means I only expect 99c back?

 

[MGP]

Does that CD/CDZ value mean that If I bet $1 i expect 99.5c back?

That's correct. If you're EV were -1% then you'd get 99c for every dollar.

Taking out pushes just makes the EV worse, as you lose more money on an average hand, because there are less hands.

When calculating EV based on the initial bet including pushes makes no difference.