Should you insure good hands?

NightStalker

Well-Known Member
#4
your calculations may also include more details

Since insurance pays 2:1. If probability of success is greater than 1/3, odds are in favor. But Insurance is related to your hands when it comes to variance, which is missing in that document.

If dealer has a ten in the hole, you are going to lose your main bet. If dealer doesn't has a ten, then there is a good chance that you will win on your 20.
Insuring good hands lowers your variance which may be the best strategy based on your affordable risk and marginal counts.

PS: I would not bet my whole bankroll on 1% edge, because of high variance.
 
#5
On The Street

NightStalker said:
PS: I would not bet my whole bankroll on 1% edge, because of high variance.
Theory:
If you only bet .5% of your bank on a 1% advantage while I bet 1% of my bank on a 1% advantage I will be far richer then you, more then twice.

Real World:
We are not sure of our advantage. We are only human and can make errors in counting or indice usage etc. So perhaps only bet .5% to .75% of bank on a 1% advantage.

:joker::whip:
 

FLASH1296

Well-Known Member
#6
There is much to be said re: taking insurance (for variance-reduction purposes)
against a BJ (or even a hand of 20) by respected sources, e.g. J. Grosjean.

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blackchipjim

Well-Known Member
#7
Math impaired

I didn't know that taking insurance when the count warrants it was a matter of wether you had a good hand or not. Correct me please but it was my understanding that if the count warrants inusurance you took it because it was a different bet then your original one. I didn't bother with looking at the math pdf. reply because I'm math impaired.
 

Cardcounter

Well-Known Member
#8
No

Don't insure a 20 what did you just use to get that 20? Probably two ten value cards these are the cards that the dealer needs to get to have blackjack and beat you. Since 2 of the tens are in your hand the dealer gets a lower percentage of blackjacks. Remember that insurance is not a bet on your hand it is a bet on the dealers. Don't insure unless you are counting 10's and the is less than a 2 to 1 ratio of 10's to other cards.
 

SleightOfHand

Well-Known Member
#9
FLASH1296 said:
There is much to be said re: taking insurance (for variance-reduction purposes)
against a BJ (or even a hand of 20) by respected sources, e.g. J. Grosjean.

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Don't worry assume_R, ill be bringing my copy of ECAA :)
 

assume_R

Well-Known Member
#10
Flash, I wanted to take into account variance too but wasn't sure how to do it. It is my guess that depending on the variance of the hand in question, it might be worth it for certain good hands based on EV/Var. Need to comb over some more math :)

Blackchipjim, the whole conclusion I made was that if you disregard variance (and only take into account EV), then insurance is only dependent on the dealer's hand. The EV of your hand cancels out. It is what I wanted to explore, or prove, to myself.

Sleight, excellent! Can't wait to take a look at it.
 

FLASH1296

Well-Known Member
#11
When looking at Risk Aversion vis a vis variance reduction — look at it this way:
Let’s say you have a hand where you have a small advantage. The opportunity
to split or double is present. You have an advantage so you need to press that advantage
by doubling your bet. So far so good. Now lets imagine that you
have a nice little advantage — lets say 2%. So you double.

Now lets look at that hand again. IF the hand matchup is to your advantage, then it is
always MORE advantageous (in terms of winning the hand) to refrain from doubling.
We can hit, retaining the right to draw further cards.
What if by doubling (a one card draw) ?
Your advantage drops from 2% to 1.25% ? So … If you double you gain 1.25% of two units,
which is more (by 0.5%) than 2.0% of one unit. SO … Why not double ?
Because you are risking twice as much for a modest increase in profit.

Now where/when/how does this make sense.

The answer resides within your Risk of Ruin.

If your risk is high (whatever that means to you), e.g.> 13%,
every time you have extra money at risk, your bankroll may
get seriously dented. You may soon have to resize your betting ramp.

If your risk of ruin is very low, e.g. < 1.0% than this issue of “money at risk” is hardly even an issue at all.

In my experience training Card Counters, (as “lone wolf“ players),
R I S K should be the paramount concern, when all too often it isn’t.
 

SleightOfHand

Well-Known Member
#12
FLASH1296 said:
When looking at Risk Aversion vis a vis variance reduction — look at it this way:
Let’s say you have a hand where you have a small advantage. The opportunity
to split or double is present. You have an advantage so you need to press that advantage
by doubling your bet. So far so good. Now lets imagine that you
have a nice little advantage — lets say 2%. So you double.

Now lets look at that hand again. IF the hand matchup is to your advantage, then it is
always MORE advantageous (in terms of winning the hand) to refrain from doubling.
We can hit, retaining the right to draw further cards.
What if by doubling (a one card draw) ?
Your advantage drops from 2% to 1.25% ? So … If you double you gain 1.5% of two units,
which is more (by 0.5%) than 2.0% of one unit. SO … Why not double ?
Because you are risking twice as much for a modest increase in profit.

Now where/when/how does this make sense.

The answer resides within your Risk of Ruin.

If your risk is high (whatever that means to you), e.g.> 13%,
every time you have extra money at risk, your bankroll may
get seriously dented. You may soon have to resize your betting ramp.

If your risk of ruin is very low, e.g. < 1.0% than this issue of “money at risk” is hardly even an issue at all.

In my experience training Card Counters, (as “lone wolf“ players),
R I S K should be the paramount concern, when all too often it isn’t.
I agree with FLASH about the RoR involved with doubles/splits, which is why I always prefer using RA indeces, which take into account the CE (which some of you know is my preferred method of comparison) of the play rather than the EV. Because CE is adjusted depending on my personal RoR, I can feel more comfortable making higher variance plays.

As for taking insurance when the count doesn't call for it, I would only do this on a BJ, A9, maybe A8 when the TC is very close to the index, where close is dependent on my hand total, but is in the order of a 1/4 to 1/8 TC away (level 2). Remember that always taking even money still is a -EV play and may or may not have a necessary cost, even though the overall cost may not be very significant. Why give up EV if you don't have to? Sure, there may be some "cover" making this move, but not all ploppies take even money. So why are we?
 

assume_R

Well-Known Member
#13
Makes sense.

So how do you decide that threshold, of how much +EV you'd need to double that bet and bet more money on the table? I guess a more generalized question would be specifically how does one generate risk averse indices? And as a corollary could you say that RA indices are somewhat dependent on your bankroll then? Because I was always under the impression there is a "hard threshold" for what a risk-averse index is (maybe pertaining to C.E.??) which isn't dependent on your bankroll.

And pertaining to some comments on my original post, a question could be what should one take into account when deciding whether or not to insure a good hand (such as a blackjack) if one wants to take into account variance reduction? Is it EV/Var or something else such as how much $$ you have on the table versus your bankroll?
 

SleightOfHand

Well-Known Member
#14
assume_R said:
Makes sense.

So how do you decide that threshold, of how much +EV you'd need to double that bet and bet more money on the table? I guess a more generalized question would be specifically how does one generate risk averse indices? And as a corollary could you say that RA indices are somewhat dependent on your bankroll then? Because I was always under the impression there is a "hard threshold" for what a risk-averse index is (maybe pertaining to C.E.??) which isn't dependent on your bankroll.

And pertaining to some comments on my original post, a question could be what should one take into account when deciding whether or not to insure a good hand (such as a blackjack) if one wants to take into account variance reduction? Is it EV/Var or something else such as how much $$ you have on the table versus your bankroll?
RA plays are ALL about CE. Instead of making the most +EV play, you make the most +CE play.
 

Sucker

Well-Known Member
#15
FLASH1296 said:
Your advantage drops from 2% to 1.25% ? So … If you double you gain 1.5% of two units,
which is more (by 0.5%) than 2.0% of one unit. SO … Why not double ?
Because you are risking twice as much for a modest increase in profit.
This is a gamblers' fallacy. You are NOT risking two bets. The first bet was already risked; before the hand started. When this situation arises, your decision is NOW whether or not to risk ONE (more) bet in order to gain 0.5%.

This is the whole reason why betting full Kelly is incorrect in blackjack. If you can't afford to make the proper plays, you're overbetting your BR. It's as simple as that. Besides; any time you decide to forego making the mathematically correct play, you're lowering your OVERALL advantage, and thereby INCREASING your variance in the long term. Plan ahead. Size your bets correctly and you won't have this problem to begin with.

Jimmy Piersall said it best: "Fear strikes out!".
 

assume_R

Well-Known Member
#17
Sucker said:
This is the whole reason why betting full Kelly is incorrect in blackjack. If you can't afford to make the proper plays, you're overbetting your BR. It's as simple as that.
Can you elaborate what you mean by betting full Kelly is incorrect? Is it because full kelly gives you a 13.5% RoR?

Also, are you implying not to use RA indices and to only use EV maximizing indices? Because if you're not, my bad. If you are implying that, I believe it was qfit who said that RA indices means that since your variance is lower, your optimal bet (based on EV/Var) is higher, thus allowing you to increase your overall SCORE. And if I'm not mistaken, flash was referring to using RA information for deciding whether or not to double in his example.
 

Nynefingers

Well-Known Member
#18
Sucker said:
This is the whole reason why betting full Kelly is incorrect in blackjack.
I believe what you said here and what you meant are not the same, although correct me if I'm wrong. I think what you mean is you should not bet, for example, 2% of your BR on a 2% edge. If that's what you mean, then I don't think that's what Kelly betting would suggest that you do. Kelly betting incorporates the variance of the bet into the optimal bet calculation, hence the advice to bet 73% (I think...going by memory on the %) of your edge. I see this concept misstated frequently. People often say something like "the optimal bet is .75 Kelly, and full Kelly is overbetting", etc. I think these statements stem from a misunderstanding of exactly what Kelly betting means. Of course, I'm no authority on the subject myself. Sucker, if you were referring to another factor that makes traditional Kelly betting suboptimal, I'd be interested to hear your thoughts.
 

psyduck

Well-Known Member
#19
Interesting discussion!

I think if one hesitates to double and/or split when his max bet is out, it only means one thing - the max bet is too large for his bank. My understanding is that doubling down and splitting contribute a lot to our win and we have to use them to the full extent.
 

assume_R

Well-Known Member
#20
psyduck said:
Interesting discussion!

I think if one hesitates to double and/or split when his max bet is out, it only means one thing - the max bet is too large for his bank. My understanding is that doubling down and splitting contribute a lot to our win and we have to use them to the full extent.
Hmm what I would say is that the question isn't whether or not to double/split when a max bet is out, but rather to wait for one more true count. For example, the EV-maximizing index for 9v2 for zen is TC +7 but the RA index is +8.

Also I'd be interested in bringing this around, and/or discussing my original post regarding taking insurance to reduce variance, of which I haven't seen any consensus on how to introduce variance into the calculations.
 
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