Risk of Ruin help

#1
Hello I had a question about my RoR. I have $4000 set aside for blackjack only as my "bankroll". I have a job so if i lose this money it can be replaced. I understand that according to many sources I am overbeting my bankroll so I would like to know my chances of losing the entire amount. I play in atlantic city and use the Hi-lo count. I stand behind the 8 deckers S17 DAS and wait for a count greater than tc+2 than jump in with one hand $200 bets until the count drops or the shoe is finished. So far I have only broken even with this tactic. Can someone please tell me my ROR? again if I lose this money it can be replaced but I would like to tell the MRS my odds of losing the 4k thank you -steve s
 

Jeff25

Well-Known Member
#2
So you flat bet 1 hand of $200 at t2 and higher. Your ROR with a $4000 BR is 65.3%, assuming 75% pen. If you jump in at t3, its 55.1%. If you were to play two hands of $100 at t2, its 53.7%.
 
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Sonny

Well-Known Member
#3
You'll earn about $35 per 100 hands and your lifetime RoR is around 66%. The odds are definitely against you. However, if you are able to suppliment your bankroll each month with some extra cash from another source then your RoR will drop. Also, dropping your bets after a significant loss will help.

-Sonny-
 

SPX

Well-Known Member
#4
So you're essentially a flat bettor who only bets in advantageous situations. As you know, $4000 / $200 bets renders a TOTAL bankroll of only 20 units.

In my opinion, if you're flat betting then this is sufficient as a SESSION bankroll but definitely not as your whole bankroll. If I were you, I would step things down a notch. I would make each session bankroll 20 units and then have 10 individual session bankrolls set aside for a total of 200 units.

However, this would drop your bet down to $20 a hand and I suspect that you're going to feel like this bet level isn't sufficient to get your blood pumping. Still, at the VERY LEAST I would drop down to $100 a hand because I've dropped 20 units in half an hour before.


EDIT: I should point out that I am speaking as a basic strategist and not a counter, but I chimed in since you don't use a bet ramp. If my advice here is incorrect, the more experienced posters here can feel free to correct me.
 
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#5
Good information - is there anyway you could figure out my ROR if 100% of my winnings went into my $4,000 bankroll assuming I win 1,000 now my bank would be 5k and so on
 

Sonny

Well-Known Member
#6
stevess75 said:
Good information - is there anyway you could figure out my ROR if 100% of my winnings went into my $4,000 bankroll assuming I win 1,000 now my bank would be 5k and so on
The RoR formulas assume that all of your winnings get reinvested into your bankroll. If you sepnd the money instead of putting it back into your bankroll then your RoR is 100%.

-Sonny-
 

Ferretnparrot

Well-Known Member
#8
Jeff25 said:
So you flat bet 1 hand of $200 at t2 and higher. Your ROR with a $4000 BR is 65.3%, assuming 75% pen. If you jump in at t3, its 55.1%. If you were to play two hands of $100 at t2, its 53.7%.
Does anybody have the actual formula that produces these numbers?
I would like to look at it to try and see why these numbers are above 50%
I still refuse to accept that with a fixed betting unit reletive to your bank (Fixed as in it does not change EVER) you can destroy it more than 50% of the time while simultaniously expecting to have more wins than losses in all of the trials combined.
 
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#9
Ferretnparrot said:
I still refuse to accept that with a fixed betting unit reletive to your bank you can destroy it more than 50% of the time while simultaniously expecting to have more wins than losses in all of the trials combined.
Another rude awakening. zg
 

Ferretnparrot

Well-Known Member
#10
zengrifter said:
Another rude awakening. zg
what? im really totally dumbfounded here, i just dont see how you can statistically lose more often than win WHILE simultaniously expectign to win more oftan than lose in the sum of all the trials, does anybody else not see that cause its totaly a valid contradiction.

I know im not crazy
 

Sonny

Well-Known Member
#11
Ferretnparrot said:
i just dont see how you can statistically lose more often than win WHILE simultaniously expectign to win more oftan than lose in the sum of all the trials…
Because in the short-term the variance can be wild. If you don’t have enough money to make it through the short-term then you will not be able to play long enough to reach the long-term. Basically, if you go broke during a negative swing then you will never see a corresponding positive swing (if there is one). If you do not have enough money to cover a small negative swing, which happens very frequently, then you probably won't last long. The fact that you have a long-term advantage doesn't do you any good if you never make it to the long-term results.

Ferretnparrot said:
Does anybody have the actual formula that produces these numbers?
I use the following formula:

RoR = ((1-EV/SD)/(1+EV/SD))^(Bankroll/SD)

Schlesinger has a very detailed explanation of this in his chapter on risk of ruin. His chapter on Trip RoR (as well as my previous example) also discusses how you can have an overall RoR > 50%.

-Sonny-
 

moo321

Well-Known Member
#12
Jeff25 said:
So you flat bet 1 hand of $200 at t2 and higher. Your ROR with a $4000 BR is 65.3%, assuming 75% pen. If you jump in at t3, its 55.1%. If you were to play two hands of $100 at t2, its 53.7%.
You have insufficient data to give a risk of ruin number. Your 65.3 % number is meaningless, because you haven't even defined the time frame.

If you have 100 units, and wong at +3 and flat-bet, your risk vs. chance of doubling is 5%. You're definitely overbetting your bankroll.
 

moo321

Well-Known Member
#13
Ferretnparrot said:
what? im really totally dumbfounded here, i just dont see how you can statistically lose more often than win WHILE simultaniously expectign to win more oftan than lose in the sum of all the trials, does anybody else not see that cause its totaly a valid contradiction.

I know im not crazy
You're right, everyone else is wrong. It looks like most of the people are plugging numbers into some software or formula and giving arbitrary risk of ruin numbers. It's been discussed in other threads, and I don't know why it persists.
 

Sonny

Well-Known Member
#14
moo321 said:
You have insufficient data to give a risk of ruin number. Your 65.3 % number is meaningless, because you haven't even defined the time frame.
The numbers are for lifetime RoR.

moo321 said:
If you have 100 units, and wong at +3 and flat-bet, your risk vs. chance of doubling is 5%. You're definitely overbetting your bankroll.
I don’t get anywhere near 5% at all. I get a 60% chance of doubling his 20-unit bankroll before going broke. That leaves a 40% chance of losing it all before doubling it. Note that he is still very likely to go broke after doubling his bankroll so this short-term RoR may not be as meaningful. Looking at the lifetime RoR will give a better idea of what he is up against.

-Sonny-
 
#15
Sonny said:
You'll earn about $35 per 100 hands and your lifetime RoR is around 66%. The odds are definitely against you. However, if you are able to suppliment your bankroll each month with some extra cash from another source then your RoR will drop. Also, dropping your bets after a significant loss will help.

-Sonny-
I dont understand how 66% can be possible. I know that I am overbetting my bankroll. The odds of me to double my bankroll before going broke has to be over 50% (common sense in my head). If your telling me that my bankroll of 4k will go broke 50% of the time before doubling twice that would make sense to me. Assuming that it would double twice my bank would be at 16k I should almost be close to "home free" with a ror probably under 10%.
 

Sonny

Well-Known Member
#18
stevess75 said:
sonny- what in your formulas would be enough bank in order to have an acceptable lifetime ror for my $200 bets?
It all depends on how much risk you are willing to take. Here are a few ballpark figures:

Code:
[U]RoR[/U]    [U]Odds of Busting[/U]    [U]Bankroll[/U]
20%	1-in-5		  $17,500
10%	1-in-10		  $25,000
5%	1-in-20		  $32,500
You can lower these numbers by adjusting your bets as your bankroll changes. You can also lower your RoR a lot by spreading more aggressively and playing a stronger game.

-Sonny-
 

Ferretnparrot

Well-Known Member
#19
I understand now if you call it a "lifetime ror" im am guessing its compared to going to infinity, a probibility of tapping out could possibly and very easily exceed 50%

Iv always viewed ror as compared to doubling and that in my mind is the default reference of ror, perhaps when we talk about ror we should specify what kinda by typing LROR or TROR or DROR

but i think its also safe to say that if you have a 65% chance of losing $4,000 and a 35% chance of having unlimited money for life, its a pretty awsome buisness plan so long as a 4000 dollar loss wont cause you to lose your home.
 
#20
Here We Go Again

When any of you make statements contradicting the long established ror equations you are contradicting many in the blackjack field who have well established reputations. Griffin, Schlesinger, Snyder and Wong among others.

Optimal betting means optimal, nothing else is as good. Certainly overbetting is not optimal. Overbetting is far worse then underbetting because when you go broke you can't play.

Lifetime ror numbers are appropriate for the short term. The variance is so high in the short term that you need a total bankroll.

Here is something to think about. For a long weekend trip you will need something along the lines of half of your bank.
 
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