Answers.Body: <p>The USCF implemented Elo's suggestions in 1960, and the system quickly gained recognition as being both fairer and more accurate than the Harkness rating system. Elo's system was adopted by the World Chess Federation (FIDE) in 1970. Fide used k=30 factor before July 2014. </p>
  
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Answers.CreationDate: 2020-05-28T07:20:23.373Z
Answers.LastActivityDate: 2020-05-28T07:20:23.373Z
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Body: <p>The change in Elo ratings depends, among other things, on the K-factor (or development coefficient). </p>
  
  <h2>Current rules</h2>
  
  <p><a href="https://handbook.fide.com/chapter/B022017" rel="nofollow noreferrer">FIDE Rating Regulations effective from 1 July 2017</a> give the following values:</p>
  
  <ul>
  <li>K = 40 for a player new to the rating list until he has completed events with at least 30 games; and for all players until their 18th birthday, as long as their rating remains under 2300. </li>
  <li>K = 20 as long as a player's rating remains under 2400.</li>
  <li>K = 10 once a player's published rating has reached 2400 and remains
  at that level subsequently, even if the rating drops below 2400.</li>
  </ul>
  
  <p>The same values have been in effect since <a href="https://handbook.fide.com/chapter/B022014" rel="nofollow noreferrer">July 1, 2014</a>. </p>
  
  <h2>Past rules</h2>
  
  <p>The <a href="https://en.wikipedia.org/wiki/Elo_rating_system#Most_accurate_K-factor" rel="nofollow noreferrer">Wikipedia page on the Elo rating</a> mentions that FIDE used the following values before July 2014:</p>
  
  <ul>
  <li>K = 30 (was 25), for a player new to the rating list until the completion of events with a total of 30 games.</li>
  <li>K = 15, for players with a rating always under 2400. </li>
  <li>K = 10, for players with any published rating of at least 2400 and at least 30 games played in previous events. Thereafter it remains permanently at 10.</li>
  </ul>
  
  <h2>My questions</h2>
  
  <ol>
  <li>When were these past rules enforced?</li>
  <li>When was the change from K=25 to K=30 applied?</li>
  <li>With the exception of this last change, have these values been applied since the beginning of Elo's creation?</li>
  </ol>
  
  <p>I take the liberty of asking all these questions at once because they're related.</p>
  
Tags: <rating><history><fide><elo>
Title: The Evolution of the K-Factor
ThreadText: # The Evolution of the K-Factor
  
  (Asked by: username_0 on 2020-04-14)
  
  The change in Elo ratings depends, among other things, on the K-factor (or development coefficient).
  
  ## Current rules
  
  [FIDE Rating Regulations effective from 1 July 2017](https://handbook.fide.com/chapter/B022017) give the following values:
  
  * K = 40 for a player new to the rating list until he has completed events with at least 30 games; and for all players until their 18th birthday, as long as their rating remains under 2300.
  * K = 20 as long as a player's rating remains under 2400.
  * K = 10 once a player's published rating has reached 2400 and remains
    at that level subsequently, even if the rating drops below 2400.
  
  The same values have been in effect since [July 1, 2014](https://handbook.fide.com/chapter/B022014).
  
  ## Past rules
  
  The [Wikipedia page on the Elo rating](https://en.wikipedia.org/wiki/Elo_rating_system#Most_accurate_K-factor) mentions that FIDE used the following values before July 2014:
  
  * K = 30 (was 25), for a player new to the rating list until the completion of events with a total of 30 games.
  * K = 15, for players with a rating always under 2400.
  * K = 10, for players with any published rating of at least 2400 and at least 30 games played in previous events. Thereafter it remains permanently at 10.
  
  ## My questions
  
  1. When were these past rules enforced?
  2. When was the change from K=25 to K=30 applied?
  3. With the exception of this last change, have these values been applied since the beginning of Elo's creation?
  
  I take the liberty of asking all these questions at once because they're related.
  
  **Tags:** rating, history, fide, elo
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2020-05-28. Score: 1
  
  The USCF implemented Elo's suggestions in 1960, and the system quickly gained recognition as being both fairer and more accurate than the Harkness rating system. Elo's system was adopted by the World Chess Federation (FIDE) in 1970. Fide used k=30 factor before July 2014.
  
  
  ---
  
  