Answers.Body: <p>If the website <em>was</em> using ELO, then that would indeed be unusual. ELO is designed to change a lot after unexepcted results (beating someone much higher rated / losing against someone much lower rated) but very little after expected results.</p>
  <p>But <a href="https://chess.stackexchange.com/questions/34097/lichess-vs-chess-com-elo-system-and-player-strength/34113#34113">Chess.com does not use ELO</a>. They are using the <a href="https://en.wikipedia.org/wiki/Glicko_rating_system" rel="nofollow noreferrer">Glicko rating system</a>. The difference between Glicko and ELO is that Glicko tries to take into account that ratings of players might have different grades of reliability. Ratings of new players in a community are notoriously unreliable due to lack of data. Players who don't play very often are also unreliable, because you don't know how much they practiced or slacked between matches. But there are also established and active players that can have widely varying performance depending on how they feel that day.</p>
  <p>In order to account for all of these reliability problems of ratings, the Glicko system calculates a &quot;Reliability Deviation&quot; (RD) for each player. This is a number that represents how unreliable their rating is. When your RD is high, then you gain or lose more points after each game (so it doesn't take too long to get closer to your actual rating). When your opponent's deviation is high, you gain or lose fewer points (because playing against someone whose rating is unreliable isn't a good way to determine your own rating).</p>
  <p>So if your goal is to change your rating quickly, try to play against players who are active and whose rating appears relatively consistent.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2024-06-19T12:41:13.963Z
Answers.LastActivityDate: 2024-06-19T12:54:17.557Z
Answers.LastEditDate: 2024-06-19T12:54:17.557Z
Answers.UserDisplayName: Philipp
Body: <p>When I am playing on Chess.com, the amount of elo I gain or lose from each game seems to be randomized, due to the fact that I gain less and lose more elo, when playing against players with a higher elo rating than me. But when I am playing against players with a lower elo rating than me, I seem to generally gain more and lose less elo.</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-06-18T19:20:37.620Z
Comments.Text: Chess.com does not use elo.  See https://support.chess.com/en/articles/8566476-how-do-ratings-work-on-chess-com
Comments.UserDisplayName: Ian Ringrose
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-06-18T19:22:56.347Z
Comments.Text: Chess.com uses the [Glicko-2 system](http://www.glicko.net/glicko.html) which includes a parameter for your rating volatility (or uncertainty). If that parameter is high (e.g., you haven't been playing a lot), the rating changes will be large. See also the [wikipage](https://en.wikipedia.org/wiki/Glicko_rating_system).
Comments.UserDisplayName: SecretAgentMan
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-06-18T19:52:57.137Z
Comments.Text: Correction:  Chess.com may use the Glicko-1 system.  (sources [1](https://chess.stackexchange.com/a/34113/26335), [2](https://www.chess.com/article/view/chess-ratings---how-they-work), [3](http://www.glicko.net/research/gdescrip.pdf))
Comments.UserDisplayName: SecretAgentMan
Tags: <rating><online-chess><computer-chess><elo>
Title: Why does the Elo I gain from games fluctuate so heavily?
ThreadText: # Why does the Elo I gain from games fluctuate so heavily?
  
  (Asked by: username_0 on 2024-06-18)
  
  When I am playing on Chess.com, the amount of elo I gain or lose from each game seems to be randomized, due to the fact that I gain less and lose more elo, when playing against players with a higher elo rating than me. But when I am playing against players with a lower elo rating than me, I seem to generally gain more and lose less elo.
  
  **Tags:** rating, online-chess, computer-chess, elo
  
  > **Comments:**
  > **username_1**: Chess.com does not use elo.  See https://support.chess.com/en/articles/8566476-how-do-ratings-work-on-chess-com  
  > **username_2**: Chess.com uses the [Glicko-2 system](http://www.glicko.net/glicko.html) which includes a parameter for your rating volatility (or uncertainty). If that parameter is high (e.g., you haven't been playing a lot), the rating changes will be large. See also the [wikipage](https://en.wikipedia.org/wiki/Glicko_rating_system).  
  > **username_2**: Correction:  Chess.com may use the Glicko-1 system.  (sources [1](https://chess.stackexchange.com/a/34113/26335), [2](https://www.chess.com/article/view/chess-ratings---how-they-work), [3](http://www.glicko.net/research/gdescrip.pdf))  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_3 on 2024-06-19. Score: 0 | Accepted answer
  
  If the website *was* using ELO, then that would indeed be unusual. ELO is designed to change a lot after unexepcted results (beating someone much higher rated / losing against someone much lower rated) but very little after expected results.
  
  But [Chess.com does not use ELO](https://chess.stackexchange.com/questions/34097/lichess-vs-chess-com-elo-system-and-player-strength/34113#34113). They are using the [Glicko rating system](https://en.wikipedia.org/wiki/Glicko_rating_system). The difference between Glicko and ELO is that Glicko tries to take into account that ratings of players might have different grades of reliability. Ratings of new players in a community are notoriously unreliable due to lack of data. Players who don't play very often are also unreliable, because you don't know how much they practiced or slacked between matches. But there are also established and active players that can have widely varying performance depending on how they feel that day.
  
  In order to account for all of these reliability problems of ratings, the Glicko system calculates a "Reliability Deviation" (RD) for each player. This is a number that represents how unreliable their rating is. When your RD is high, then you gain or lose more points after each game (so it doesn't take too long to get closer to your actual rating). When your opponent's deviation is high, you gain or lose fewer points (because playing against someone whose rating is unreliable isn't a good way to determine your own rating).
  
  So if your goal is to change your rating quickly, try to play against players who are active and whose rating appears relatively consistent.
  
  
  ---
  
  