[TNixon]

One final go.

Since you're now claiming that I don't understand what the original question was, or what everybody's been talking about all along, lets take a quick (or not so quick, as the case may be) look.

The original post is quite clearly a question about frequency and size of downswings.

Your math can only possibly answer questions about the odds of having a drop of size X starting RIGHT NOW. In fact, this comment:
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Jason1990's solution gives you the probability that you will achieve a downswing of size x commencing after time t .
This is very different from dropping x buy-ins commencing from t=0 .

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shows that you do actually realize this. Jason's solution gives the probability of having a downswing of size x at *any* point over a given time interval, while your approach gives the probability of having a downswing of size x starting RIGHT NOW. That is what you just said, so you do realize that, unless your writing comprehension (and in, understanding what you just wrote) is as bad as your reading comprehension.

What completely boggles me is that you think your approach is what people mean when they're talking about swings of size X. "How likely is having a 20BI drop over a month" isn't a question of how likely it is that the month will START with a 20 BI drop, it's a question about how likely it is to have a 20BI drop *at any point through the entire month*. Because of that very basic lack of understanding on your part, it completely amazes me that you believe you have actually contributed anything of worth to this discussion.

But lets take a trip down memory lane, since obviously one of the two of us needs to re-read the thread, and see what everybody else has been talking about.

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I think if the stakes are reasonably low and your style isn't too aggressive/bluffy most of your downswings will be in the neighborhood of 5-10 BIs.

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A comment about the average size of drops. Your math can only possibly answer questions about whether a drop is starting RIGHT NOW. You cannot even begin to make comments on the frequency or likelyhood of drops at any point over a given time interval.

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but i dont think 20 bi downswings are impossible for even decent players. But day to day variance, you shouldnt let losing 5 or 6 buy ins affect you cos that will become sooo standard

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More comments about frequency and size of drops, which your approach is completely incapable of addressing.

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swings of more than 7-8 BuyIns should be pretty uncommon

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If you can only answer whether a 7-8 buyin drop is starting RIGHT NOW, then how can you possibly comment on how common 7-8 buyin swings might be?

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According to my simulations even a 50 buy-in downswing is possible with a stable winrate of 8 PTBB/100 (no tilting/other psychological defects allowed) although it'll be extremely rare. That is for a player whose standard deviation per 100 hands is about 75PTBB/100. 20BI downswings seem to be quite common.

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More comments on the frequency of downswings of a particular size. Again, your approach simply cannot even begin to answer "how likely is it for me to have a 50 buyin-downswing at *some* point. Your approach can only answer "how likely is it that I am going to start a 50 buyin downswing RIGHT NOW".

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20+ BI downswings will happen to a full time player probably monthly.

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Another comment on the frequency of 20+BI downswings. Jason's solution is *perfectly* relevant here, and can actually tell you how likely it is to have at least one 20BI drop per month. (again, if you don't believe the formula itself is valid, then you're on your own, but you don't appear to have made that claim yet)

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And what does "quite common" mean here? Just a ballpark would be good, like an average number of 20BI downswings in 10k hands (or 100k or 500k hands or whatever if 10k isn't enough).

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This is *MY* specific question.

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Er, correct me if I'm wrong, but it looks like you've calculated a 1.1% risk of ruin when starting with 20 buyins, but said absolutely nothing about how likely a 20 buy-in downswing is over any given X number of hands.

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And this is a clarification to *MY* specific question. From this point on, what you thought the *original* poster was asking (even though you botched the comprehension there, too), is completely irrelevant, because any argument or discussion from here on out should be based on the question I was asking.

If I'm asking one question, and you're answering another question, and you're trying to tell me that I'm not asking the question that I'm asking, then who's the idiot here?

If you don't think my question is the same as the original poster's question, then that's the point you should have been arguing all along. This could have been a whole lot shorter and less flameful. You'd still be an idiot, because they're exactly the same, but maybe you could have avoiding ending up looking like a fool.

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In any case , I computed the ror of a player with a win-rate of 8ptbb/100 hands and a s.d of 150 ptbb/100 hands to be 5.81% .

The probability of losing 20 buy-ins in a month must be lower than this number .


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This is your first provably false statement in the thread. I proved in a variety of ways that for *MY* question (which in my opinion, matches the original poster's question, but whether it does or not is, again, irrelevant), the chance of a drop of size X over Y hands can quite clearly be greater than the RoR for a bankroll of size X. Again, your lack of comprehension intrudes, and apparently that all goes way over your head, because you STILL don't know what question is actually being asked.

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The biggest downswing I've had was about 9-12 buy-ins(btu there were 2-3 mistakes for stacks), also I could've had S.D. 150bb/100, if played more agro. So I feel that 20 buy-in swings is possible once a month (considering how bad I was running sometime, and it COULD'VE BEEN even worse), and 30 buy-ins downswings once in a quarter(playing 30K hands a month)

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Another comment about the frequency and size of downswings. Seeing a pattern here? Everybody's talking about a situation that you have no answer for, because you're answering the wrong question, and your approach cannot possibly begin to comment on what *is* being discussed.

From that point on, everybody else leaves the thread, and flames begin to fly, but at that point, any argument is over *MY* specific question, whether it's the same as the original poster's or not. (and again, I believe that you are completely off-base here and simply do not understand what people mean when they are asking about frequency and size of swings)

And quite frankly, your attempts to tell me that I don't know what question *I* am asking are so completely beyond pathetic, that after this, I think I have to try to take sweetjazz's advice, and quit making a fool of myself through further argument.