user-1: I play correspondence since many years ago. I have been playing in lichess for years having a rating ~1900-2000. I recently open a premium account in chess.com and I started to play 50 simultaneous games. I couldn't pass throw 1500 rating while my tactics trainer rating is 2600 and I returned to play in lichess.
I know there are some reasons why chess.com has stronger players with the same rating than lichess ones, but analyzing the games I faced players that do have plus than 95 of accurancy in complicated games, so I think the reason may be those player use engines at least when the move is complicated, as they are rated 1500 and not making blunders. This is not what I found in lichess where profiting of blunders allow me to beat easily 1500 or even 1700 players.
I read a post of Erick, the owner of chess.com saying cheating happens at a +2300 level. But my concern is, at a lower level and in correspondence, I miss blunders in chess.com. In lichess I have not troubles to reach 1900-2000 rating beating easily the 1500 players. I think those users are using engines when the position is complicated but playing a fair game the rest of the game. That might evitate them to be catched and allow them to play at a 1500 level while they are poor players that should have a rating <1500. I have seen other users that have a curve of rating that grows and decreases. I think when they loose rating they start to use the engine so they can mantain a rating and play the games they want to play with overrated players than them.
chess.com is a big entreprise, they should have programmers versed in machine learning techniques to detect cheaters. Are lichess programmers better than chess.com and succeded to send cheaters away from his correspondence rooms even at low rating levels while chess.com programmers not? Do they use similar technics or lichess ones are more sofisticated?
Or it is just a matter about rating strenghts and I am being paranoic?
It might be just 1500 rated players make blunders in lichess while chess.com 1500 rated players not?

user26993: Just about the cheating, cheaters are not the smartest, and that's why there are algorithms which can detect cheaters. Those algorithms are not the smartest either, and that's where the differences are. Most cheaters have really powerful engines playing for them, but don't pick the best of the best move because the most basic anti-cheat would detect that (except if you are titled as BOT). That's why they pick the second, third of fourth line the engine suggests. If this behaviour is happening a lot of the moves (which could variate between Lichess and chess.com), a cheat could be detected. If you play about the same time per move in combination (that margin can also differ and this can be bypassed by using different depths) with this, that means you are playing against Stockfish instead of Irsu85.
The chances are also low a human can see a very complex but winning line with a hundred pins after 30 ply. This could also be used in anti cheat, but I don't know if that is a thing on chess.com or on lichess

user1766: The dynamics of postal chess allows more in-depth analysis of the games. This makes mistakes rare. Some sites prefer to maintain the rule that in correspondence chess you should not use assistance of any kind (as if it were face-to-face chess) and others have reasoned that it is too difficult to know if chess engines or other assistance have been used. For example, the International Correspondence Chess Federation, (ICCF) allows the consultation of tables of endings of seven pieces to decide the winner of the ending of a game. I guess to save time at the big tournaments.
Some tournaments are centered on certain openings (thematic tournament) and others are pure competition. In the latter, the chess player must foresee the opponent's move, either by investigating the lines of play that can be derived from the position or if suspect that his opponent uses engines to chose his moves, consider also the lines that an engine would choose, especially in the opening to take him to a disadvantageous position due to a better understanding of the strategy and trying to uncoordinate the opponent's pieces, so that can't benefit from the engine.
In the middlegame, some player can choose the type of endgame he prefers and look for, for example, a triple repetition draw or aim for an endgame with more than seven pieces to prevent his opponent from benefiting from the Lomonosov endgame tables.
Now, the reason why you suspect that chess_com players rely more on engines than Lichess players, its perhaps an appreciation that should be validated comparing the analyses of correspondence games from same players on both platforms.
Your hypothesis could be explained by the slow pace that makes difficult for chess_com or Lichess to monitor the use of engines by the players, because somebody spending an hour or more time of analysis, could discover moves that the reference engine (stockfish on chess.com an Lichess) won't detect as an engine move.
Another reason could be that Lichess and chess.com may process suspicions of cheating differently.

user18809: Different sites have different rating systems and player pools. They're not directly comparable. Lichess ratings tend to be higher than chess.com ratings for the same reaosn a person's weight tends to be higher than his height

user825: Different website have a different rating scale. I'm sure lichess gives higher rating than chess.com for the same player. In fact, the lichess rating is also higher than the FIDE rating. I personally know a lot of FIDE 2200 rated players achieve ~ 2600 on lichess, equivalent to GM on FIDE scale (but they are not GM).
I'm personally also a few hundred ELO points behind on chess.com than lichess. I've found much more challenging to defeat a chess.com 2000 rated player than lichess 2000.

user20677: Chess.com is a for-profit business, so they have more incentive to be sure that a player is cheating before banning a potentially paying customer. Since lichess is fully free, there's less cost associated with a false positive ban. Thus it would make sense for chess.com to have a higher threshold of confidence for banning cheaters, but I can't say whether this motivation does actually impact their choices or not.

-1: <p>I play correspondence since many years ago. I have been playing in lichess for years having a rating ~1900-2000. I recently open a premium account in chess.com and I started to play 50 simultaneous games. <a href="https://www.chess.com/member/manuel_i_muro_sabater" rel="nofollow noreferrer">I couldn't pass throw 1500 rating while my tactics trainer rating is 2600</a> and <a href="https://lichess.org/@/Manuel_Muro_Sabater" rel="nofollow noreferrer">I returned to play in lichess</a>.</p>
<p>I know there are some reasons <a href="https://chess.stackexchange.com/questions/34097/lichess-vs-chess-com-elo-system-and-player-strength">why chess.com has stronger players with the same rating than lichess ones</a>, but analyzing the games I faced players that do have plus than 95 of accurancy in complicated games, so I think the reason may be those player use engines at least when the move is complicated, as they are rated 1500 and not making blunders. This is not what I found in lichess where profiting of blunders allow me to beat easily 1500 or even 1700 players.</p>
<p>I read a post of Erick, the owner of chess.com saying cheating happens at a +2300 level. But my concern is, at a lower level and in correspondence, I miss blunders in chess.com. In lichess I have not troubles to reach 1900-2000 rating beating easily the 1500 players. I think those users are using engines when the position is complicated but playing a fair game the rest of the game. That might evitate them to be catched and allow them to play at a 1500 level while they are poor players that should have a rating &lt;1500. I have seen other users that have a curve of rating that grows and decreases. I think when they loose rating they start to use the engine so they can mantain a rating and play the games they want to play with overrated players than them.</p>
<p>chess.com is a big entreprise, they should have programmers versed in machine learning techniques to detect cheaters. Are lichess programmers better than chess.com and succeded to send cheaters away from his correspondence rooms even at low rating levels while chess.com programmers not? Do they use similar technics or lichess ones are more sofisticated?</p>
<p>Or it is just a matter about rating strenghts and I am being paranoic?
It might be just 1500 rated players make blunders in lichess while chess.com 1500 rated players not?</p>
 26993: <p>Just about the cheating, cheaters are not the smartest, and that's why there are algorithms which can detect cheaters. Those algorithms are not the smartest either, and that's where the differences are. Most cheaters have really powerful engines playing for them, but don't pick the best of the best move because the most basic anti-cheat would detect that (except if you are titled as BOT). That's why they pick the second, third of fourth line the engine suggests. If this behaviour is happening a lot of the moves (which could variate between Lichess and chess.com), a cheat could be detected. If you play about the same time per move in combination (that margin can also differ and this can be bypassed by using different depths) with this, that means you are playing against Stockfish instead of Irsu85.</p>
<p>The chances are also low a human can see a very complex but winning line with a hundred pins after 30 ply. This could also be used in anti cheat, but I don't know if that is a thing on chess.com or on lichess</p>
 1766: <p>The dynamics of postal chess allows more in-depth analysis of the games. This makes mistakes rare. Some sites prefer to maintain the rule that in correspondence chess you should not use assistance of any kind (as if it were face-to-face chess) and others have reasoned that it is too difficult to know if chess engines or other assistance have been used. For example, the International Correspondence Chess Federation, (ICCF) allows the consultation of tables of endings of seven pieces to decide the winner of the ending of a game. I guess to save time at the big tournaments.</p>
<p>Some tournaments are centered on certain openings (thematic tournament) and others are pure competition. In the latter, the chess player must foresee the opponent's move, either by investigating the lines of play that can be derived from the position or if suspect that his opponent uses engines to chose his moves, consider also the lines that an engine would choose, especially in the opening to take him to a disadvantageous position due to a better understanding of the strategy and trying to uncoordinate the opponent's pieces, so that can't benefit from the engine.</p>
<p>In the middlegame, some player can choose the type of endgame he prefers and look for, for example, a triple repetition draw or aim for an endgame with more than seven pieces to prevent his opponent from benefiting from the Lomonosov endgame tables.</p>
<p>Now, the reason why you suspect that chess_com players rely more on engines than Lichess players, its perhaps an appreciation that should be validated comparing the analyses of correspondence games from same players on both platforms.</p>
<p>Your hypothesis could be explained by the slow pace that makes difficult for chess_com or Lichess to monitor the use of engines by the players, because somebody spending an hour or more time of analysis, could discover moves that the reference engine (stockfish on chess.com an Lichess) won't detect as an engine move.</p>
<p>Another reason could be that Lichess and chess.com may process suspicions of cheating differently.</p>
 18809: <p>Different sites have different rating systems and player pools. They're not directly comparable. Lichess ratings tend to be higher than chess.com ratings for the same reaosn a person's weight tends to be higher than his height</p>
 825: <p>Different website have a different rating scale. I'm sure lichess gives higher rating than chess.com for the same player. In fact, the lichess rating is also higher than the FIDE rating. I personally know a lot of FIDE 2200 rated players achieve ~ 2600 on lichess, equivalent to GM on FIDE scale (but they are not GM).</p>
<p>I'm personally also a few hundred ELO points behind on chess.com than lichess. I've found much more challenging to defeat a chess.com 2000 rated player than lichess 2000.</p>
 20677: <p>Chess.com is a for-profit business, so they have more incentive to be sure that a player is cheating before banning a potentially paying customer. Since lichess is fully free, there's less cost associated with a false positive ban. Thus it would make sense for chess.com to have a higher threshold of confidence for banning cheaters, but I can't say whether this motivation does actually impact their choices or not.</p>
