This is a strong point in Hans's favor, and Regan is very reputable, but he's also going against the Chess.com team (and Hans himself!) in claiming that he finds no evidence of Hans cheating *online* either.
The best expert on opining whether Niemann has been cheating or not is the player who understands the game of chess more deeply than anyone else. He understands it from the human point of view (for example: which variations can a player of X or Y level calculate accurately, which ones might seem to work but are in practice too complicated/too risky to play, which moves are absolutely unbelievable from a human because one has to find ten super moves in a row starting from a non-forcing position) as well as from the engine's point of view, due to his experience in analysing with computers. He also has recent experience in playing Niemann in a tournament.
I trust that Carlsen knows what he is doing.
>includes having the entire tree of variations for every position in your mind while investigating
Too bad even Magnus can't do that and the closest you can get is by writing software to do it for you.
You did not describe the algorithm or the data which would help writing the software you are talking about. As I said, for me if this software would be based on comparing the engine's best move with the human's move and give such metrics as average centipawn loss, it would not be nearly adequate for this purpose.
And I insist that all the things you described as the hardest part are only poor substitutes for understanding the game of chess.
Wow.
Regan has been an active and respected member of scientific community, a lecturer and book author for a long time. If anything that adds and not takes away from his credibility. He's also the most prominent expert on cheating detection that FIDE has ever worked with and he's an authority on the matter.
Oh, and he's rated at around 2400 ELO. But I guess it's very easy to just slander him like that. Go back to reddit.
“I would take Regan’s analysis with the large grain of salt, and the reason why is not because I have any insight into his algorithm or his methods, but because I know of a case of, a very high profile case, where with absolute certainty I can say that someone was cheating in an important event. And the person was investigated and was also exonerated based on Regan’s analysis. And I am certain that there was cheating. There is no doubt in my mind that this person was cheating and they got away with it.“
So this is one more example of an academic, who is so far away from reality and practice, that real experts just ignore his opinion.