You Are Spreading Too Much

#1
Since the dawn of card counting, blackjack players have been told that they must spread their bets in order to make any serious amount of money off their play. The only restriction has been the unknown, subjective, arbitrary, and post hoc limits imposed by casino management. Don Schlesinger has discovered that smaller spreads in backcounting simulations do not give up much versus larger ones in terms of SCORE, but a stronger observation results from use of certainty equivalent (CE) as the measure of risk-adjusted winnings.

It turns out that if optimal CE is used as the standard, the departure from canon is even more dramatic. I have used Norm Wattenberger’s CVCX site to note the results of his sims with six-deck games, and there is a point beyond which spreading one’s bets actually REDUCES risk-adjusted expectation.

As an example, let’s pick a semi-safe, prevalent six-deck game currently available at various minimums up and down the strip. It is particularly identified with one of the largest casino chains, appearing at several of their properties. Better games exist, but this one is common enough and safe enough that it can serve as a bread-and-butter game for shoe players and teams. We will disguise it by calling it the Moderately Good Money game. The rules are S17, DAS, LSR, 4.5/6.

According to Wattenberger’s data, the CE with the HiLo + I18 + F4 is maximized when the spread is 1-25 (with backcounting, of course). If you spread less than this, you give up some bucks in exchange for camo, but if you spread more than this, you are actually decreasing your CE!

The gain for tamer spreads can be expressed as a percentage of the maximum:

Spread CE CE/max
2 $25.54 0.890827
3 $26.87 0.937217
4 $27.40 0.955703
5 $27.70 0.966167
6 $28.11 0.980467
8 $28.48 0.993373
10 $28.65 0.999302
12 $28.66 0.999651
15 $28.66 0.999651
20 $28.66 0.999651

Wonging in was at +2 for spreads of 2 to 4 and at +1 for larger spreads; these values were of course chosen to optimize CE. Note that for a spread of 1-12, the player gives up only one cent versus the CE, establishing that this spread for the game in question is a lot more efficient than was perhaps realized previously. The 99% mark is achieved with a spread of 8 (and perhaps 7, which I was too lazy to check, although linear extrapolation implies 7 would be inadequate). If you have been swept up by the current emphasis on change in American political discourse, use a 1-5 spread: you will give up only 97c, less than a dollar, versus the theoretical maximum.

The pattern of a spread that maximizes CE persists in one-deck and two-deck games. However, the spreads that maximize CE tend to be in the hundreds for playable pitch games and are of less interest as a practical matter. I investigated the 1d, H17, NDAS, 0.6/1 game and the 2d, H17, DAS, 1.4/6 game on Wattenberger’s page and found that the CE-optimal spreads were between 200 and 400 in each case.

I haven’t bothered to check yet to see if anyone else has “discovered” this tendency, so if I’m inventing the telephone for the second time, so be it. Regardless of how “original” my insight is, however, shoe players who have taken pride on having such a good “act” that they can spread 1-100 or more can stop working on their act now: they’ve overdone it.
 

bj bob

Well-Known Member
#3
Very interesting!

So, if I'm reading your list correctly. It would seem that a 1:6 spread would get you virtually all the way to the "sweet spot" as long as you're playing all TC 2+. If so, that should have massive ramifications on RoR and BR requirements.
 

EasyRhino

Well-Known Member
#4
Why do I feel like I walked into a middle of a debate, where I don't know what the topic is?

If your point is, that when backcounting, a large spread isn't necessary between small and big bets, then I'd agree. As long as you're betting zero in neutral/negative counts, then you don't have to worry too much.

And, once in positive counts, the goal is to bet proportionally to your advantage. So, for instance, a 4% advantage bet would be 8x as much as a 0.5% advantage bet. A 0.5% advantage occurs somewhere around +1 or +2. A 4% advantage occurs at or around TC+9, (so it's not too bloody likely.) So in this rather aggressive case, you're looking at an 8x spread.

It would seem to me that a bigger spread would be merely "forcing" bet changes where they are neither needed or justified?

Of course, if you're playing negative hands, the goal would still be to bet as close to zero as possible.
 

bj bob

Well-Known Member
#5
EasyRhino said:
Why do I feel like I walked into a middle of a debate, where I don't know what the topic is?

If your point is, that when backcounting, a large spread isn't necessary between small and big bets, then I'd agree. As long as you're betting zero in neutral/negative counts, then you don't have to worry too much.


It would seem to me that a bigger spread would be merely "forcing" bet changes where they are neither needed or justified?

Of course, if you're playing negative hands, the goal would still be to bet as close to zero as possible.
I don't think there's really any controversy here, it's just that Mr. "O" has pretty much pin pointed optimum spreads in that Wonging situation.
The more interesting stat was his analysis of the optimal spreads for pitch games. Just think, Easy! A 200 spread on SD. I bet you're drooling all over your kitchen table right now while booking your flight to the High Sierra.:grin:
 

EasyRhino

Well-Known Member
#6
Mr. O, I'm assuming that the figures for pitch games assume that there is no backcounting? In which case, I'd agree that a near-infinite spread would be preferable, until one gets the inevitable boot.
 

sagefr0g

Well-Known Member
#7
OMendoza said:
Since the dawn of card counting, blackjack players have been told that they must spread their bets in order to make any serious amount of money off their play. The only restriction has been the unknown, subjective, arbitrary, and post hoc limits imposed by casino management. Don Schlesinger has discovered that smaller spreads in backcounting simulations do not give up much versus larger ones in terms of SCORE, but a stronger observation results from use of certainty equivalent (CE) as the measure of risk-adjusted winnings.
.....................................................................
.........., however, shoe players who have taken pride on having such a good “act” that they can spread 1-100 or more can stop working on their act now: they’ve overdone it.
some day i'm gonna have to learn more about this SCORE and CE stuff.
but anyway regarding getting by with a lesser spread i think your not referring to play all. just curious if there is a similar tapering off of gains realized by larger spreads for play all as well.
 

jack.jackson

Well-Known Member
#8
UAPC vs RAPC vs RoR(play-all)

It would be Interesting to see how the Uston APC and RAPC'71 would fare in sims, with 1-4 spread in a double deck game vs 6decks. Then see how the difference compares to a 1-24 spread. In my opinion the UAPC, would win with the 1-4 in both the 2D and 6D games. But as soon as you change the spreads to 1-24 the RAPC would win both. The difference has to do with the high PE of the UAPC(.692) and the high BC for the RAPC (.997)
 
#9
EasyRhino said:
Mr. O, I'm assuming that the figures for pitch games assume that there is no backcounting? In which case, I'd agree that a near-infinite spread would be preferable, until one gets the inevitable boot.
The pitch game figures are for playing hands with TC of +0 or better. Technically, I suppose, the player would be wonging in if he left a shoe on a negative count and then returned if a nonnegative count emerged later. I think that that is how Norm Wattenberger had it set up. I would like to see a sim where if a player wonged out he had to stay gone, i.e. started over with a new shoe instead of effectively hanging around trying to wong back in. Still, the data are stimulating as is.
 
#10
sagefr0g said:
some day i'm gonna have to learn more about this SCORE and CE stuff.
but anyway regarding getting by with a lesser spread i think your not referring to play all. just curious if there is a similar tapering off of gains realized by larger spreads for play all as well.
Looks like it. I extracted some more data from the 1d, 2d, and 6d games I examined earlier. These are play-all spreads.


1d
Spread CE
2 $9.61
4 $34.48
8 $59.36
16 $77.32
32 $88.56
64 $94.96
128 $97.36
256 $98.27
512 $98.66
1024 $57.40

2d
Spread CE
2 $1.53
4 $14.26
8 $31.05
16 $44.74
32 $54.01
64 $59.54
128 $62.74
256 $64.57
512 $65.20
1024 $24.26

6d
Spread CE
2 $0.12
4 $4.64
8 $11.77
16 $18.00
32 $22.31
64 $24.87
128 $26.33
256 $24.73
512 $25.90
1024 -$33.95

That little bimodal bump in the 6d data worries me. I have been proceeding under the assumption that any local maximum would also be an absolute maximum. Guess not. However, the old-fashioned view of the function as monotone increasing is severely battered by the data here and in my previous, don't-play-all, scenario, which I think is enough of a discovery to show the whole project in retrospect to have been time well spent.
 

sagefr0g

Well-Known Member
#11
OMendoza said:
Looks like it. I extracted some more data from the 1d, 2d, and 6d games I examined earlier. These are play-all spreads.
..........
lol foregive me for unceremoniously but respectfully temporarily dotting out you data. but i will look it over and try and understand it. i do appreciate your response. just wanted to offer up a thought or a question regarding the perhaps unfounded assumption that spreading higher and higher may or may not be a stairway to heaven.
it's as far as i know at least pragmatically true that over betting at least along the lines of exceeding twice one's optimal bet leads to disaster. but that is probably just an aside issue. maybe, who knows an issue that carrys with it other things going on behind our backs that who knows may become more important as a bet spread increases. lol i dunno. but certainly the idea of ever increasing a spread involves certain pragmatic issues.
all that not withstanding i suspect other things do happen as we say push the envelope with a bet spread relative to our bankroll. i think this is evidenced by my disasterous nerve wrenching practice session contest with jack the ghostrider jackson wherein we are saddled a 1:10 spread on a $5000 bankroll yeilding a circa 24.6% ROR :eek: . http://www.blackjackinfo.com/bb/showpost.php?p=77490&postcount=34
again that's just a pragmatic thing but it does make one wonder if other hidden things are going on as a spread increases that don't bode well for the player. things like maybe the standard deviation becoming a larger issue to where there are more chances to sink the ship or it takes longer and many more hands to overcome the chances of fate. lol
 

bj bob

Well-Known Member
#12
Several thoughts and observations

Firstly, I would like to be able to visually perceptualize these concepts. Would it be possible to take these results and provide an overlaping graph i.e. 1D, 2Dand 6D which would display the precise points at which the "meat" of the max value can be achieved? Such a graph would also illustrate the non-linear rate of gain vs. spread points.
Secondly, As to the Wong in @TC+2, it seems to me that a specific specialized betting sequence can be formulated for this particular deck/ shoe "atmosohere" which not only would optimize the advantage viz.a viz. the TC but also compress the effective bet spread so as to appear completely innocuous to surveillance. In other words, the 6D(+2TC) betting pattern would loosley mimic that of an ineffective shoe spread or one resembling a play-all 2D spread.
 
#13
The Floor is Higher Then the Ceiling

When backcounting If you bet optimally then the spread is not that great. At each TC you have an optimal bet. Very high advantages are rare so we are placing very large bets rarely. Since you are betting only positive hands or close to that then the spread is reduced.

When playing all the spread widens because one is playing negative hands which can be a deep floor where you want to bet as little as possible. The positve hand bets are not as high as when backcounting. This acts as a limiting factor on the spread when betting optimally.

If betting optimally and with the rareity of high advantages the ceiling is not unlimited. Also, in the real world there may be table limits that limit the bets to the heavens.
 

EasyRhino

Well-Known Member
#14
If the single/double deck numbers assume playing TC +0 and higher, then that would still include a decent number of hands with a negative expectation. Which is, I think, why the "infinite" bet spread still looks appealing. Playing only hands TC +1 or higher would probably make a difference.
 

Kasi

Well-Known Member
#15
sagefr0g said:
that's just a pragmatic thing but it does make one wonder if other hidden things are going on as a spread increases that don't bode well for the player. things like maybe the standard deviation becoming a larger issue to where there are more chances to sink the ship or it takes longer and many more hands to overcome the chances of fate. lol
I don't really understand it all either but I think any different fixed spread with defined entry points might have it's own optimal points. I guess that point being when the ratio of variance vs EV is lowest?

So the reason back-counting is better than spreading is that, although stan dev has increased it hasn't increased as much as the EV.
 
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