Answers.Body: <blockquote>
  <p>I would expect national ratings (assuming, of course, that they use a system compatible with ELO, e.g. Germany) are constantly below FIDE ones, and the larger and more active the nation is, the smaller the difference</p>
  </blockquote>
  <p>This false expectation is based on the usual mistake of believing that ratings are some kind of absolute measure of chess playing ability. They are not. They are always purely relative measures with limited time validity.</p>
  <blockquote>
  <p>my personal experience suggests that in average German DWZ is about 100 points lower than ELO</p>
  </blockquote>
  <p>And if you talk to Americans they usually tell you that their <a href="https://chess.stackexchange.com/questions/13663/convert-between-different-rating-systems#comment17816_13663">USCF rating is about 100 points <em>higher</em> than their FIDE rating</a>.</p>
  <p>When I played and arbited in Israel the generally accepted formula for conversion between the two ratings was ICF = FIDE + 90. I even remember arbiting in a tournament which was limited to players with ICF rating under 2290! A stranger number until you remember the formula. When I moved to England and stopped playing ICF rated chess I was curious as to what would happen to my ICF rating. It stayed in synch with my FIDE rating! The ICF monitors my FIDE games played and updates my ICF rating accordingly.</p>
  <p>Note that there have been questions regarding conversions between different rating systems. <a href="https://chess.stackexchange.com/questions/13663/convert-between-different-rating-systems">This one</a> in particular gives formulae which may have applied at the time but are unlikely to apply now.</p>
  <p><a href="https://chess.stackexchange.com/questions/13663/convert-between-different-rating-systems/13689#13689">This answer</a> from 6 years ago gives a complicated formula for converting between USCF and FIDE. It may have been accurate then. It is unlikely to be accurate now.</p>
  <p><a href="https://chess.stackexchange.com/questions/13663/convert-between-different-rating-systems/13693#13693">This answer</a> gives a formula (FIDE=7.5xECF+700) for converting between ECF and FIDE which is just wrong. It is debatable whether it was right at the time, despite being officially used by the ECF (I remember FIDE = 8xECF+600), but then ECF ratings had 3 digits and now they have 4. My current ECF rating is just under 1900 while my FIDE rating is just over 1700.</p>
  <p>Bottom line: national, international and online ratings can only be meaningfully compared within the individual systems. Comparisons between systems are meaningless.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-05-30T19:56:47.320Z
Answers.Text: That USCF-FIDE formula in the linked answer is still officially used by the USCF. No idea if it's still accurate.
Answers.UserDisplayName: D M
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-06-01T06:55:20.210Z
Answers.Text: I wouldn't agree to the bottom line that comparisons are *totally* meaningless (since a "perfect" rating system would not "drift" and the difference of two systems should be more or less constant - the problem obviously being that the player played against other people in comparison) but as the German database is currently down, I have no data to back this up...
Answers.UserDisplayName: Hauke Reddmann
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-06-04T11:17:57.553Z
Answers.Text: I not convinced that USCF is truely a single rating system as so many players only play other players from the same area.
Answers.UserDisplayName: Ian Ringrose
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-05-30T13:03:53.803Z
Answers.LastActivityDate: 2022-05-30T13:03:53.803Z
Answers.UserDisplayName: Brian Towers
Body: <p>For extreme cases see <a href="https://chess.stackexchange.com/questions/22013/experience-of-big-difference-between-elo-and-national-rating">here</a>, but I'm interested in statistical averages.</p>
  <p>The most skewing factor, as already mentioned there, should be underrated players, which simply haven't played against the &quot;big fish&quot; yet. That said, I would expect national ratings (assuming, of course, that they use a system compatible with ELO, e.g. Germany) are constantly below FIDE ones, and the larger and more active the nation is, the smaller the difference.</p>
  <p>For example, my personal experience suggests that in average German DWZ is about 100 points lower than ELO (and for my own rating, this is even true over decades of active play!). But that's no proper way to do stats. Does anyone have validated data, especially for different countries which confirm or deny my naive assumption?</p>
  
Tags: <fide><rating><statistics>
Title: Difference between national and international rating
ThreadText: # Difference between national and international rating
  
  (Asked by: username_0 on 2022-05-30)
  
  For extreme cases see [here](https://chess.stackexchange.com/questions/22013/experience-of-big-difference-between-elo-and-national-rating), but I'm interested in statistical averages.
  
  The most skewing factor, as already mentioned there, should be underrated players, which simply haven't played against the "big fish" yet. That said, I would expect national ratings (assuming, of course, that they use a system compatible with ELO, e.g. Germany) are constantly below FIDE ones, and the larger and more active the nation is, the smaller the difference.
  
  For example, my personal experience suggests that in average German DWZ is about 100 points lower than ELO (and for my own rating, this is even true over decades of active play!). But that's no proper way to do stats. Does anyone have validated data, especially for different countries which confirm or deny my naive assumption?
  
  **Tags:** fide, rating, statistics
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2022-05-30. Score: 5 | Accepted answer
  
  > I would expect national ratings (assuming, of course, that they use a system compatible with ELO, e.g. Germany) are constantly below FIDE ones, and the larger and more active the nation is, the smaller the difference
  
  This false expectation is based on the usual mistake of believing that ratings are some kind of absolute measure of chess playing ability. They are not. They are always purely relative measures with limited time validity.
  
  > my personal experience suggests that in average German DWZ is about 100 points lower than ELO
  
  And if you talk to Americans they usually tell you that their [USCF rating is about 100 points *higher* than their FIDE rating](https://chess.stackexchange.com/questions/13663/convert-between-different-rating-systems#comment17816_13663).
  
  When I played and arbited in Israel the generally accepted formula for conversion between the two ratings was ICF = FIDE + 90. I even remember arbiting in a tournament which was limited to players with ICF rating under 2290! A stranger number until you remember the formula. When I moved to England and stopped playing ICF rated chess I was curious as to what would happen to my ICF rating. It stayed in synch with my FIDE rating! The ICF monitors my FIDE games played and updates my ICF rating accordingly.
  
  Note that there have been questions regarding conversions between different rating systems. [This one](https://chess.stackexchange.com/questions/13663/convert-between-different-rating-systems) in particular gives formulae which may have applied at the time but are unlikely to apply now.
  
  [This answer](https://chess.stackexchange.com/questions/13663/convert-between-different-rating-systems/13689#13689) from 6 years ago gives a complicated formula for converting between USCF and FIDE. It may have been accurate then. It is unlikely to be accurate now.
  
  [This answer](https://chess.stackexchange.com/questions/13663/convert-between-different-rating-systems/13693#13693) gives a formula (FIDE=7.5xECF+700) for converting between ECF and FIDE which is just wrong. It is debatable whether it was right at the time, despite being officially used by the ECF (I remember FIDE = 8xECF+600), but then ECF ratings had 3 digits and now they have 4. My current ECF rating is just under 1900 while my FIDE rating is just over 1700.
  
  Bottom line: national, international and online ratings can only be meaningfully compared within the individual systems. Comparisons between systems are meaningless.
  
  > **Comments:**
  > **username_2**: That USCF-FIDE formula in the linked answer is still officially used by the USCF. No idea if it's still accurate.  
  > **username_0**: I wouldn't agree to the bottom line that comparisons are *totally* meaningless (since a "perfect" rating system would not "drift" and the difference of two systems should be more or less constant - the problem obviously being that the player played against other people in comparison) but as the German database is currently down, I have no data to back this up...  
  > **username_3**: I not convinced that USCF is truely a single rating system as so many players only play other players from the same area.  
  
  ---
  
  