Comment by ecshafer

Chess.com has some cool blog posts about it from a year or two back when there was some cheating scandal with a big name player. They compare moves to the optimal move in a statistical fashion to determine if people are cheating. Like if you are a 1000 ELO player and all of a sudden you make a string of stockfish moves in the game, then yeah you are cheating. A 2400 ELO player making a bunch of stock fish moves is less likely to be suspicious. But they also compare many variables in their models to try and sus out suspicious behavior.