300BB downswings are not normal. PERIOD!

[Turning Stone Pro]

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Fing yawn. Boring old debate. 300bb swings happen even when you're playing great. Period. End of arguement. next case.

Here we go again though.

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I agree with BK. This thread sucks, its been gone over so many times. Just takes up space. Let's get on to important business.

TSP

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You're more likely to have a 300 BB downswing than go broke with a 300 BB bankroll.

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Huh?

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To go broke with a 300 BB bankroll, you will almost always have to have a downswing >300 BBs. Example: If you win 20 BB when you start, you have to go on a 320 BB downswing to go broke. OTOH, you can never go broke with a downswing < 300 BBs.

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Here is another example that illustrates how likely a 300BB downswing is. Lets say I have a 5% risk of ruin with a 300BB bankroll.

Let also assume that every time I win 100BB, I cash out and round my bankroll down to 300BB.

Each time I do this I start out with a 5% risk of ruin. What happens if I do this 30 times?

The chance of my not going broke each time is .95, so the chance that I don't go broke in all 30 trials is .95 to the 30th power which equals .21.

So there is a 79% chance that I will go broke (and experience a downswing of 300BB or more) during one of the 30 trials. Wow, that is depressing.

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First, as I understand it, the ROR with a 300BB bankroll if based on the assumption of never cashing out.

That aside, even if it did not, your example is not correct. What you have done is artificially inflate the number of "trials" by indexing it to something totally unrelated to variance--in this case a cashout at 100BBs. You might as well say that the player should cash out any surplus at the end of any 24 hour period when they are over 300BB, or every time the buffet serves mussels, or based on the phase of the moon. It still doesn't affect variance or the ROR.

To make this point clear, you could just as easily say "Hey what if you cashed out 1+ BB every single time you were at 301+ BB". Then you'd have an absurdly high number of "trials" in a very short period of time, and by your logic the player would be virtually guaranteed to go broke extremely quickly. Clearly, something has gone wrong. One cannot use artificial benchmarks like a cashout to calculate one's chances of losing 300BB over a certain period of time.

The 5% rule is, imho, quite unclear as it has been stated on here and elsewhere. Everyone's risk of ruin is different. It depends on SD, true winrate (which we can never really know), and a host of other factors. I am not fully familiar with the math behind it (though now I think I will become familiar with it), but it seems the 300BB/5% rule gets tossed around here rather indiscriminately sometimes, and the math/logic in the discussions of it is often pretty sketchy.

For what it's worth, I agree with the OP. A 300 BB downswing should be an extremely rare occurance for a good player (particularly one with a low variance, low SD style), and many of the "downswings" I see posted on here are probably the result of the snowballing of bad luck, bad play, and the resultant bad image causing opponents to take more shots/play better.

[SoBeDude]

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Well, the real question is: if 100 winning players tell me that they had a 300BB downswing, how many of them are experiencing a normal occurence?

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Who the [censored] cares?! This question and the answer to it hold absolutely ZERO relevance re: statistics and 300 BB downswings. If you really think that any information pertaining to this subject can be gleaned from this, "the REAL question", you should just shut up. You've shown pretty clearly in this thread that you don't know [censored] about what you're talking about, which would be fine if you would submit that this theory of yours is just a thought in your head and not something that can be backed up by statistics.

GoT

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It's a tragic shame, that 2+2 doesn't require their representatives in these forums to conduct themselves with a modicum of civility.

-Scott

[SoBeDude]

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This is seriously incorrect.

The ROR is not cumulative, starting every time you cash out.

By your gorilla math, If I have 300BBs and have a 5% ROR, I then make 20 BBs and cash them out, I suddenly have a 10% ROR!??

Do you see how silly this is now?

The ROR is calculated NOT as a 1-shot deal, but as a long term player, trying to maintain a 300BB Roll.

Nice how you add your statements as fact though, and add to the general confusion of the typical reader.

-Scott

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Scott,

Nice cute and smug retort of yours there.

However, you are wrong. He is right. The risk of ruin has not increased. In his example, he has cashed out a lot of money. So, when he goes broke in one on the trials, he is not "ruined" as he still has money. However, he did go through a 300bb downswing, which is the topic of this thread. BTW, I did not check his math, so that may or may not be right, but his approach is sound to illustrate the point (300bb downswing is signficantly more common than RoR given 300bb roll).

Of course, with the abysmal level of math and logic knowledge often displayed on this forum, poor game selection, overestimation of expected edge in certain situations, and a number of other factors, the chances of the average poster here having a 300bb+ downswing are sky-high.

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I disagree (with the first part of your response). regardless of what he's taken out in winnings, his ROR doesn't increase algepraically over time. This is ludicrious.

AND, in the second part, do you realize you just supported Rigo's position? All those factors you mentioned are legit reasons for having a 300 BB downswing, but are contrary to the premise that they occur all the time to solid players.

Nicely done.

-Scott

[SoBeDude]

Nicely put.

-Scott

[SmileyEH]

Well here's some non handwavy math (or at least I think it is). These graphs assume an SD of 18.

Chance of a -2SD downswing = 2.3%
Chance of a -3SD downswing = 0.135%



Essentially the OP is right. A 300BB downswing is very very rare. For a 1BB/100 winner we're talking every million hands or so. And a 2BB/100 winner should over several lifetimes worth of play never have one.

-SmileyEH

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My understanding is that the Math that produces the 300 BB figure assumes a player whose result for each session are produced by a single bell curve, with a mean and standard deviation. This assumption is ridiculous (I don't fault those who have worked with it, since it simplifies a lot of calculations).

Has anyone heard of a Markov model? Suppose a Dr. Jekyll and Mr. Hyde each play and track their results as one. Dr. Jekyll is a small winning player and Mr. Hyde is a big losing player. 80% of the sessions are played by Dr. Jekyll. What's the chance of a 300 BB downswing now? Not the same as before, you need separate computations. I think this is something like what happens during a 100 BB downswing. A better hypothesis is that Mr. Hyde has been playing, not that random variance has occurred.

(of course, this assumes 2 personalities. there can be 3, or 4, or more...)

[SoBeDude]

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My understanding is that the Math that produces the 300 BB figure assumes a player whose result for each session are produced by a single bell curve, with a mean and standard deviation. This assumption is ridiculous (I don't fault those who have worked with it, since it simplifies a lot of calculations).

Has anyone heard of a Markov model? Suppose a Dr. Jekyll and Mr. Hyde each play and track their results as one. Dr. Jekyll is a small winning player and Mr. Hyde is a big losing player. 80% of the sessions are played by Dr. Jekyll. What's the chance of a 300 BB downswing now? Not the same as before, you need separate computations. I think this is something like what happens during a 100 BB downswing. A better hypothesis is that Mr. Hyde has been playing, not that random variance has occurred.

(of course, this assumes 2 personalities. there can be 3, or 4, or more...)

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OK, you're supporting the original premise of this thread. That MOST OFTEN, the big downswings are caused by the Mr. Hydes in all of us (poor play), and not because Dr. Jekyll got unlucky over a long stretch.

Nice analogy!

-Scott

[Ulysses]

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I disagree (with the first part of your response). regardless of what he's taken out in winnings, his ROR doesn't increase algepraically over time. This is ludicrious.

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You continue to fail to understand the fact that a 300BB downswing and "ruin" are not the same thing.

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AND, in the second part, do you realize you just supported Rigo's position? All those factors you mentioned are legit reasons for having a 300 BB downswing, but are contrary to the premise that they occur all the time to solid players.

Nicely done.

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Once again, your logic is atrocious. The fact that players like you w/ poor math and logic skills are more likely to have a 300bb downswing has absolutely no impact on the % time a solid player playing well will encounter such a swing. Unless, of course, he's in the same game as you.

[disjunction]

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OK, you're supporting the original premise of this thread. That MOST OFTEN, the big downswings are caused by the Mr. Hydes in all of us (poor play), and not because Dr. Jekyll got unlucky over a long stretch.

Nice analogy!

-Scott

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Yeah, I pretty much agree with the original premise. It could be poor table selection as well.

Of course, this way of thinking is dangerous to a lot of gamblers. They'll emerge from a 300 BB downswing and think that they've just made some adjustment to their game that will change their results, and start tracking from scratch.