I feel like eventually the amount of views of this post will become more than the hands in my database...
Just to add another worthless concept to a rediculous thread.

Again, you can use Baysean Statistical Inference to blend expert oppinion and data.

Also, you can quantify the liklihood that this is the result of survivor bias.

I think assuming this guy is a lottery winner based on intuition is not very rigorous, to say the least. Greater minds than ours thought and convinced the world that heavier objects fell faster than lighter ones because it was intuitively obvious.

Great explanation!

Another thing to note is that the confidence interval is based on the assumption that BB/100 winrate follows a normal distribution, which isn't necessarily a good assumption.

Hi Eric

Thank you for taking the time. It does look like I'm wrong on this, but if I'm learning that's all good. But I still need to wrap my brain around something:

Your assertions would also seem to imply that DERB can not run a confidence interval on his own stats. I mean, we have determined that confidence intervals doesn't apply. Let's for arguments sake assume that the 100K hands we are talking about are all the hands DERB has ever played; how can the confidence interval then apply to one analysis and not another.

Aren't we confusing a (very small) sample of players (only DERB) with the sample of hands. Granted there is a relationsship between his sample of hands and the key numbers we chose him from, but does this really mean that a sample of 100K hands are rendered meaningless just because we went looking for a LAG that is a winning player?

Let's imagine I where to look up 30/18 (or there about) players with a good winrate in a huge database and I find 100 of them. Now running a confidence interval on this sample of 100 players and their 4 key stats will tell me that they are likely winners because that's why I picked them (the confidence interval is meaningless like in your coin example). But when I look closer I find that 99 of these players stat's are based on less than 100 hands while one is based on 100K hands. Doesn't this make a difference! Intuition tells me that the key figures from the guy with 100K hands are more reliable than from the 100 hand guys. It also seems to me that doing a confidence interval on the 100 hand guys will tell us that they could be anywhere from big loosers to big winners, while the confidence interval on the 100K hands points to a winner.

I can't really find a good coin analogy for this one.

I might be way off here, but if a top tier professional...say Phil Ivey were to play 30/60 on PartyPoker, would he demolish the game? Or is the difference between the best 30/60 players on PartyPoker and Phil Ivey a very slim margin? If, by chance, DERB turns out to be a top tier professional, is it hard to believe he can play so many hands and still win? I'm just throwing out another possibility.

"Your assertions would also seem to imply that DERB can not run a confidence interval on his own stats."

He can, but he would be using incomplete information to come to his conclusion. That's the problem. If he had no other knowledge of the situation other than his own win rate and SD, this would be his best bet. We are working with additional information. If you win 6-9 BB/hr with 99% confidence according to a Z-table, and no one else in the world wins more than 3 BB/hr, there is clearly greater than a 1% chance you win less than 6.

"but does this really mean that a sample of 100K hands are rendered meaningless just because we went looking for a LAG that is a winning player?"

They are not rendered meaningless. They are mitigated to a significant (but arguable in magnitude) extent.

Thanks! I appreciate it!

I think comparing Loj to someone with his preflop stats is of very limited use. He has a very distint style of play and is certainly not your average donk. Much like there are a lot of donkeys who play with "good" preflop stats.

-f

If we really want to learn something about DERB what we need to do is look at his future hands from this point on. The data up to this point is what we used to select him, that data is biased. Future data is not.

If we flip 1000 coins 1000 times and have a coin that is 4-sigma away from the mean it may be an unfair coin, but because of selection bias we don't know (its in fact not shocking to have a coin 4-sigma out in this situation). To find out if the coin is fair we flip that coin another 1000 (or whatever) times and we can then apply a confidence interval to those results because they aren't biased.

So lets wait a few months and then look at DERBs data from today (or maybe the op date) and draw conclusions from that sample. That data won't suffer from selection bias.

Personally I think the gap between top players and avg party players is much smaller in limit. In no-limit the skill factor can override the fact that he's paying extra SBs to call so many hands (30% vpip, right?) whereas in limit he can only earn so much per pot, so the extra bets lost would kill his winnings.

I've been reading this thread for a while now, and I got frustrated enough that I had to register and post.

The coin analogy doesn't work.

When you use the coin analogy you are already assuming that DERB must be a losing player, or at the very least that he (or she) will, in the long run, have EXACTLY THE SAME results as everyone else with 30/18 stats. THIS is what is being debated, therefore you cannot begin your argument that he is a bad player by using analogies that assume he is as bad as the 30/18 players you're used to.

When you toss a coin, however many times, you know before tossing it that in the long run, the numbers will tend toward 50/50 because you know that there are only two potential results, and they are both equally likely.
DERB's play might very well not be anywhere close to what you're used to seeing with players with his stats. As has been discussed, there is a great deal more to a player's success than PT stats, and I think if anything is going to be figured out, this is the place to start.
So DERB could be a 2BB/100 winner on a hot streak, or he could still be that 5%, 1%, or 0.3% lottery winner (or a big fat cheater, but I've seen no evidence of that).

All I'm saying is that you CANNOT use the coin analogy because you are simply assuming that all players with DERB's stats - stats taken using a method that doesn't paint nearly a whole picture of how a player plays - will ALWAYS tend toward a certain BB/100.

You are basing your argument on your conclusion. This is fallacious.

My 2 cents, this is all very interesting.

-Matt

Dead on. I hope someone who knows who this guy is actually does this!

Yes, I wrestled with this as well.

First of all, let's note that just because your confidence interval calculation is invalid, it doesn't mean that DERB is a loser. I happen to think it's likely he is a losing or break-even type player and he's on a major hotstreak, but I haven't given any proof of this. This is just speculation based on the few hands I've seen posted. All I've "proved" is that a confidence interval calculation is invalid in this instance when it comes to pinning down this guy's true win rate.


Ok, moving on. DERB of course chose his own stats randomly beforehand, so he does have an unbiased view of his own stats. So he believes, correctly, given the information he has, that he is 99.7% likely to be a winner.

I think the reason we can put him at a much lower percentage than this is that we have more information than DERB, or at least, than the hypothetical DERB that just naively runs a confidence interval on his play with no other thought. Here are the things we know that his simple calculation does not take into account:

1. he is the farthest outlier in a large sample of datamined players. This virtually guarantees that he is on the very high side of the variance. It's virtually impossible that this one guy has a true win rate ten times higher than anybody else and is running bad. Right? In his simple worldview, he is just as likely to have below average results as the very best.

2. we can analyze the hands he's playing and see that he's making substantial mistakes that aren't consistent with someone winning this much money. The poker information contained in the hands we see him play is much more convincing and "converges" much faster than the rather naive confidence interval calculation DERB is doing himself. I made another post on this a while ago. If you look at the hands and see that a player is making major mistakes, that's a much better indicator than a confidence interval of a player's true win rate. DERB is making these mistakes himself so he probably cannot recognize them as a major indicator that he is just one of the 1 in 600 players or so that will run this good, and not the world beater his confidence interval calculation suggests.

Hope that helps.
-Eric

Hey, I don't even play 3/6 let alone 30/60 but since this thread has actually forced someone to register in order to post in it, I thought I would chime in, too. I think you're missing the point of the analogy. No one is saying that you have to assume that the coins are all fair before you do the experiment. Let's say that you take 1000 coins and you flip them each 1000 times and you DON'T know whether they are fair or not. If you take the one that lands on heads most and try to make an argument that it MUST be weighted to land on heads more often by building a confidence interval, that argument will be wrong. That argument will be wrong because even IF all of the coins were fair coins, you would STILL expect one of them to land on heads a lot more often than tails. And by selecting that particular one to analyse, you are biasing your analysis. So you can't construct a confidence interval around its results by (implicitly) assuming that it was randomly chosen. That is what the analogy is supposed to show: that having someone perform extraordinarily can be explained even IF they are no different from anyone else.

RIG I think its time to bow down!

I agree with what you end with here, but MY POINT is that you DON'T know that he is "no different from anyone else." Additionally, I agree that you can't look at it as a completely isolated incident, but going to the other end of the spectrum and just assuming that the guy HAS to be a fluke is ignorant and teaches us nothing. If you're going base your argument and analysis on the assumption that he is just a bad player on a hot streak, then you're not going to learn why he might be beating the game in a different way that you are.

Respectfully,

Matt

No one was using the coin example to prove that he was NOT a winner, it just illustrated how confidence intervals, as they were being used, can't prove that he IS a winner. The arguments that he is not a winner came from logical analysis of how he plays his hands.

I bow for no pokerplayer

By I do thank JV, Justin and Eric for the lessons.

is it me?

are you asking if you are DERB? If so, PM me your party handle and I will tell you.

Im a stat undergrad / data mining grad student. this statement alone shows you dont really understand statistics. BTW if you cannot figure out his pp screen name then you have no business asking for it.

Edit: I appologize, Im a little drunk.

-Brad

would someone be willing to write a quick thread summary? i mainly want to know if anyone has figured out what his deal is.

James,

You seem to have played alot of hands vs this guy, whats your won from/lost to stats against him. I haven't seen anybody ever discuss this stat before so maybe its meaningless, I'm just curious if this guy is taking money from the TAGs as well as donks or just the donks.

Theres a bad player who was been winning at about 3bb/100 for about 100k hands. Some people think he cheats, others think he is good, others think he is breakeven or small winner running good, yet others think he is actually a losing player running good.

Andrew Prock is an idiot.

James282 rules.

NLSoldier rules too.

There was some argument about DERB's confidence interval regarding his winrate and Justin A and Elindauer showed why we cannot really use these confidence intervals to analyze DERB.

I think I got it all. Still no real conclusions.

edit-Oh yeah, J V rules as well. Not only did he start this awesome thread, he also added some nice Vida pics

I have a question. How many other Party 30/60 players have stats of 3BB/100 or more over 100k hands? And what are their stats?