[pzhon]

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hasnt it been heavily discussed that poker is not gaussian, and our stdev is a load of crap?

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Not really. There were long threads, but most of the posts were not written by people who understand the relevant mathematics. Lots of the posts were saying, "Can someone translate this into English?"

Has any evidence been given that shows a significant difference from the normal approximation for this purpose? In the long run, the Central Limit Theorem says the deviations from the mean are roughly Gaussian. This doesn't apply directly to downswings, but it applies indirectly. The downswings are not much different for poker outcome distributions than they are for normal distributions. By the way, poker players would love to believe poker is special and extreme, but from the mathematical perspective, the distribution of poker outcomes is pretty tame. It's not clear whether poker outcomes should produce slightly larger or slightly smaller downswings than Brownian motion.

Regarding the standard deviation, what I saw was a statement that PokerTracker has an error in its calculation of the standard deviation, and the statement that this error would be severe if you play a session of 100k hands. Ok, but no one plays sessions of 100k hands. How large is the error when you play more reasonable sessions of a few hundred to a couple of thousand hands? A few percent? Then the bankroll guidelines might be off by about twice that.

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quotes like an 8ptbb winner has 1% ror with 9 buyins just feel plain niave.


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Why, because you trust anecdotal evidence more than mathematics? I happily bet the other way. The analysis of a mathematical model, done properly, is much more reliable than stories from people who exaggerate, who are not objective, and who don't describe the context properly. E.g., they tell you of a downswing, but not that they switched from NL $100 FR to NL $200 6-max before hitting the downswing, and that they might not be able to beat the new game. They just hope it is variance. You don't hear from the people who didn't have that downswing. Rational bankroll management is about balancing the very real cost of playing in games too small with the risk of ruin, not making sure your bankroll can handle the worst recorded downswings, so anecdotal evidence is not particularly useful.

Still, the worst downswings people report are smaller (in buy-ins) at NL $10 than at NL $400. My worst downswing at NL $25 was between 4 and 5 buy-ins. My worst dowswing in slightly more NL $100 hands was 11 buy-ins. That's not surprising because my win rate was much higher at NL $25, as is typical.

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maybe its just a bad example because nobody runs at 8ptbb anymore, except maybe live players.

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There are still plenty of people winning at 8 PTBB. $10,000 against $1000 says I can do it at NL $5. Maybe it is no longer achievable at NL $600, but it's still possible at many lower levels. I think 30 PTBB/100 is still sustainable for pennies, and lower rates that are still over 10 PTBB/100 are sustainable in other microstakes games. The FAQ covers those levels, and it should be correct for those levels. If 20 buy-ins is right for NL $25, it is wrong for NL $2 and NL $400.