if you're on KGS use this:

http://kgs.gosquares.net/

basically you'll find over a large enough period of time, you're just winning or losing about 50% of the time

And here is where naive thinking about streaks (good or bad) goes wrong. The outcome only about 1 in 20, not very likely you say (if there were no cause). But how about if you played 200 games? Now how likely that you would not experience that streak somewhere in there? Or if 20 people each played 20 games, how likely that none of them would have experienced that streak. Understand? The person in the throes of a losing streak that by chance would be 1 in a 100 feels that there must be something wrong with their play. But out of 1000 people playing that many games it would be very unlikely if some of them didn't have that experience by chance. The "why me" is misplaced.

If you have 100 honest coins and you flip each 5 times it is very likely that at least one coin would come up heads each time. Not meaningful to ask "why that coin?".

This would all be very reasonable if we were discussing coin flip competitions instead of playing go, but we aren't so it isn't.

That is a mistake in thinking. Let me give an example (realistic to go).

Suppose we decide to hold a "dan promotion tournament". The rule for this tournament will be that each player entered will play four games. The winners of their games will play each other, the losers of one game each other, the losers of two games each other, and same with the losers of three games. Only a player that wins four games will receive promotion.

OK, lets say that there are 64 players contesting for this promotion. I can tell you with absolute certainty that there will be exactly four promotions. The go playing ability of the contestants is completely irrelevant to that outcome. It doesn't matter if 32 of the 64 are of proper strength to be promoted to dan because only four can win all four of their games. It doesn't matter if none are above 4 kyu. If they are allowed to enter this tournament four of them must win all four of their games.

See, just like coins.

You are assuming that just because these are humans playing go there must be a reason why the ones that won four games won them, that they must be the better players. Wrong. They could all be so drunk they can't see straight or they could all be 25 kyu players where 75% of their moves are mistakes and the outcome would be exactly they same.

Whenever we try to draw conclusions from events (find correlations) we are always needing to consider whether our observations are departing from purely random by a great enough likelihood.

I did explain in the beginning the probable evolutionary reasons why our brains are likely to overestimate the existence of patterns (to see patterns where there really aren't any). The cost of not spotting a real pattern is high while the cost of imagining patterns where there aren't any is low (because the behaviors learned likely cancelling out, as likely to be correct as wrong since there wasn't a real pattern). In other words, we are (correctly) "programmed" to perceive "streaks" because a real pattern looks the same.

Just because there is a likelihood that the slump is merely a random and to be expected event does not mean that there is no cause for it. Do we know that he is playing just as good as ever? Is it not possible that his slump is because he has been playing worse? In another thread, he asked for advice about the transition from the opening to the middle game, and mentioned that he is just starting to learn about the fuseki. Is it not probable that his attempt to integrate new knowledge is what's been getting him into trouble? If this is the case (or some other real reason for his current sub-par play), then Speedchase is right, and the statistical probability of a slump is just irrelevant.

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Patience, grasshopper.

When teaching statistics I explain that if everyone in the world tossed a hundred coins then there is a very good chance that someone would get 100 heads. If you were that person then I doubt very much that anyone could convince you it was simply by chance.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

True, but go is not entirely a game of chance, right?

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Patience, grasshopper.

You'd have more issues convincing others that this person was using a fair coin. This is by far the real problem.

Well, that is actually how I put it to them, but in the current context the concept of a biased go board does not make sense.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

Perhaps not, but if the handicap and komi are set right then it should still be a 50-50 proposition.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

Not a biased board, but sandbagger/gifted individual etc could apply as concepts.

Komi aren't set to match up individuals correctly, neither are handicaps. Even the EGF approach for ratings bears this out.

I think you misunderstood my post slightly. If you play five games in a row, there is a just over 2% chance (ignoring that playing is never a coin toss) that you will win (or lose) all five. That doesn't mean that there isn't a better explanation.

A timely comment from the speedster. Deja vu all over again. Let us not forget that we have had some discussion on this streak business before, kicked off by speedchase's famous 18-straight winners. In the end there may be some better explanations, but then again, there may not.

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Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

Nitpicking, but 1/32 is more like 3%

What we are really talking about is knowledge, how we obtain certain forms of knowledge and our certainty about whether what we believe to be true is or is not true.

Let's say that we "know" 100 things each at the 95% confidence level. For any one of these things considered individually we might feel confident that its true knowledge. But at the same time, if we were correct about that confidence level calculation, we can be reasonably certain that we are mistaken about quite a few of those 100 truths.

So back to humans playing go and these are not coins but still ..... if we have 100 humans playing go and four of them experience a five game losing streak we can correctly conclude:
1) It is about as likely as not that there was a REAL REASON in the case of one of them. Maybe even in the case of two of them. But again about as likely as no no reason for any of them.
2) It is possible, but extremely unlikely, that there is a reason for all of them. The probability, were this purely chance, that none of 100 coins each flipped five times came up five tails is quite low.
Back to the example, if ten of those players experienced a five game losing streak we could properly conclude:
1) In the majority of those cases there was a reason as extremely unlikely if 100 coins were flipped five times there would be as many as ten of them coming up five tails.
2) BUT (a very big but) we have no way of knowing which.

How people think about these things has a bearing on how we operate in various fields of endeavor. Thus in the experimental social sciences, it is considered that the 95% confidence level is very adequate for publishing results. But thought of in a different way, out of 100 papers so published, much more likely than not 4-6 of them are total male bovine manure and we have no way of knowing which.

What the people talking about coin flipping are saying is not that human go players are coins but that we don't know if in this situation the outcome we are seeing is because "human, there is a reason" or "coin, there is not" and they are trying to distinguish by comparing against the expected results were they all coins.

You seem intent on making my point for me. Would you disregard the bulk of scientific research humans have accrued because for each paper there is a 5% chance that is wrong? Similarly, is it reasonable to tell someone who is in a slump that it is more likely a chance occurrence than an actual slump? What if you consider that even a chance occurrence perceived as a slump could cause an actual slump purely by virtue of the psychology involved?

Well, as far as modern research goes, so very little of it is repeated, that I feel fairly comfortable disregarding it, not to mention the fact that a majority of the research is trying to invent or market merchandise which has little redeeming social value, or medicine that is barely effacacious, so even if it is true, I have little motivation to regard it anyway.

Really? Maybe you should try applying a little "game theory" analysis (game theory is about the value of choices, not about games per se).

That the "payoff" if the drug is used and it does work is usually so much higher than if no drug is used is the reason that we tend to accept the results of medical research at so very much lower level of confidence. People don't bother publishing results in say Physics unless a couple of orders of magnitude more certain the results weren't chance. Rightly so.

The psychological consequences of experiencing a "slump" (unfavorable run) are another matter. So perhaps is the effort to seek a cause even though there might not be one if the cost of doing that isn't too high and the gain if there is a reason and it can be corrected is high enough. That's why the folks here who are saying the situation should be evaluated against chance.

This would be possible if the head appears in 80% of all throws.

No, I think he meant all coins are 50/50 even heads or tails.