Is Hans Niemann cheating? – Expert analyzes

Regan's analysis is a good deal more detailed than that. He claims that if you check the computer just three times a game, he is going to catch you within three games. Now, if you check just once, it becomes a lot harder.

For the game against Carlsen, he looked at the key moves in that game. The first 20 or so moves were theory. You can't ever prove cheating in theory. After they diverged from theory, Regan said there were only two really key moves. For both of those, Niemann did not use the computers top choice. One of them he played a downright inaccurate move that could have cost him a tempo.

I don't know if Niemann cheated or did not, or even what exactly Carlsen suspects, but Regan's analysis seems to me to be strong enough that it counterbalances the known character deficiency of Niemann.

Regan claims that if you consult the computer just three times during a game, he will catch you after three games. If you consult just once, it gets a lot harder.

As a guy who tried writing my own chess engine, it's pretty trivial to modify a chess engine in such a way that looking for "chess engine like moves" won't work.

Take a high end engine, start messing with it's piece square tables. Modify or turn off the opening book and end game tablebases, and add slight changes to the evaluation function (e.g. slightly modify piece values.

Even doing just two of the things listed above is enough to destroy fingerprinting techniques.

I agree. The number one error made by people with statistical knowledge is to assume independence of events. Even very smart and very educated people tend to make this mistake rampantly. I hypothesize it is due to the education curriculum being very slanted in the direction of assuming independence everywhere because it makes the math easier, but I can't prove this. In the real world, true and full independence should be considered an exception rather than the norm.

Saying that Neimann is a very good chess player is basically a restatement of the fact that his previous records are likely clean. Nobody was accusing him of constant cheating before. (Cheating once is relatively easy. Cheating continuously, in multiple different environments, and leaving no trace, is hard.) The entire question at hand is essentially "Is Neimann's probability of cheating correlated with playing Magnus Carlson?" (and a family of similar questions can be asked) and no amount of analysis of his games not played against Magnus Carlson will answer that.

As for why the probability of cheating would be correlated with playing Magnus Carlson, again, no amount of consulting the statistics will be able to answer that question, but for anyone who is a human being with human foibles the answer is fairly obvious.

Someone used to double checking premises will observe that there's not much in this question statement specific to Neimann. The fact that he's cheated before does raise his particular probability, but you could ask this about anyone. And my reply to that would be, yes, that is indeed how things work, and is exactly why these high stakes games are played with more formality and more security than a pick-up game in a city park. Neimann's prior cheating does raise the question with a bit more urgency, but we generally assume a priori that anyone might be interested in cheating in a game with Magnus Carlson, and high level play in general, and act accordingly.

agarden in a sibling post suggests that the analysis itself goes deeper, which sounds more interesting. I am speaking only to what is in the linked article. It would be far from the first time a reported simplified a complex and nuanced argument into something useless, and I thought the point about independence is still worth posting.

>this really weird brute force statistical analysis

Care to explain why you call the method "really weird"? Is there a flaw in the statistics that you can correct?

Here's [1] his publications - all well cited, his h-index is good, and I find no refutation of complaints in the literature about his methods. He seems quite competent in this area.

>how you can state there's no reason whatsoever to suspect him of cheating is absurd

If cheating does not show up in performance then is it cheating? If there is any performance gain then it should show up at some statistical level.

[1] https://scholar.google.com/citations?user=8nk9k5oAAAAJ&hl=en...