What is the probability that Hans Niemann cheated in the September 4 chess game against Magnus Carlsen in the Sinquefield Cup?
Background: https://www.nytimes.com/2022/09/13/crosswords/hans-niemann-magnus-carlsen-cheating-accusation.html
Resolution
If conclusive evidence emerges, resolves to YES if he cheated or NO if he did not. Otherwise, resolves to market probability at the time of close.
The market close time will be quasi-randomly extended if there is still ongoing trading activity; using a procedure similar to that described in https://manifold.markets/MartinRandall/is-the-sky-blue-resolves-to-mkt. This is to avoid encouraging big last-minute trades to move the market. The close time will be no earlier than 10/15 and no later than 10/30.
(The intent is if the market collectively decides for example 75% chance that he cheated based on the available evidence, then this market should end up at about 75%.)
Related:
Close date updated to 2022-10-16 7:09 am
Close date updated to 2022-10-30 11:59 pm
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People are also trading
I don't understand the huge update down, what are people's reasoning? Here's mine: I think the report told us roughly what I already expected but with a significant update up on likelihood of cheating - still no evidence of cheating in the Magnus Carlssen game specifically (as expected, of course chess.com wouldn't have evidence on that specifically) but even more evidence of cheating in previous games than I expected. The increased evidence about a pattern of cheating also causes me to increase my belief that Niemann cheated against Carlssen.
Chess Investigation Finds That U.S. Grandmaster ‘Likely Cheated’ More Than 100 Times
An internal report reviewed by The Wall Street Journal alleges a previously unknown pattern of likely widespread cheating by Hans Moke Niemann, the player whose September victory over Magnus Carlsen has rocked the chess world
Relevant part of report (page 3):
Despite the public speculation on these questions, in our view, there is no direct evidence that proves Hans
cheated at the September 4, 2022 game with Magnus, or proves that he has cheated in other OTB games
in the past.
That said, as set forth more fully below in Section X, we believe certain aspects of the September 4 game
were suspicious, and Hans’ explanation of his win post-event added to our suspicion. As to his OTB play
more generally, in Section VII below we discuss what we believe are apparent anomalies in Hans’ rise in
OTB rating. Of note, we discuss how Hans became the fastest rising top player in Classical OTB chess
in modern recorded history much later in life than his peers and did it after we had removed him from
playing on our site in 2020.
Despite these potential suspicions, as shown below in Section VIII, an in-depth review of Hans’ OTB
games using Chess.com’s statistical methods revealed aggregate patterns of play that, while interesting,
are possible for a rising player approaching 2700. In Section IX we present Hans’ top performing events
based on his overperformance in strength and rating. We are prepared to cooperate with FIDE and respect
their role in leading this, and any, future OTB investigations.
“Games like this, where you voluntarily trap the knight for twenty moves and then show it was never really trapped at all 🤔
https://www.reddit.com/r/chess/comments/xqvhgh/chessbases_engine_correlation_value_are_not/ 'Chessbase's "engine correlation value" are not statistically relevant and should not be used to incriminate people'
Magnus and Hans were paired again in a new tournament, and Magnus resigned on the second move of the game:
https://www.reddit.com/r/chess/comments/xii899/magnus_carlsen_resigns_after_two_moves_against/
The basic facts are that Magnus was playing a known cheater (who has lied about the extent of his cheating, according to chess.com), said known cheater beat him in the first game they ever played, and with the black pieces (the first time Magnus has lost with white in almost two years), and the reason he won was he "got lucky" and happened to have recently prepared an obscure sideline of a random opening.
I don't think we know if he did cheat, but I think it's entirely reasonable for Magnus to suspect he did.
I think that one of the contending theories is that Hans won by taking advantage of a leak of Carlsen's prepwork. Would that be cheating? From what I see, probably not (unless Hans hacked him to obtain the data, for example, which would be a different story than a leak and would be cheating). In any case, here's a market on that:
I find all of these stories very amusing, but it seems to me that if Hans was cheating, he'd almost definitely have stopped after this whole thing blew up to avoid risking being caught with the increased scrutiny. So I don't see the point of checking him for cheating in the games he's playing now, other than as a formality.
@Imbens this question is not about whether conclusive evidence emerges (because I don't think that's especially likely), it's just about whether he cheated. If the market collectively looks and the evidence and decides 75% chance of cheating, then it ought to resolve 75%
@FRCassarino This type of resolution method has actually been used a fair amount. This particular way of dealing with the close date is a little experimental, another I've used successfully in the past is just declaring the market will close at a quasi random time in a given window of a couple days. It's generally worked reasonably well in my experience.