3

By now there were 4 games and all were drawn. Should it not mean that Caruana should get points?

  • 3
    They are too close in rating. Any change in draw is within rounding errors. – SmallChess Nov 14 '18 at 15:19
9

The exact workings of FIDE rating calculations can be found in the official rules. As you can see in Table 8.1b, a rating difference of 3 points (as is the case with Carlsen-Caruana) means that both players have the same expected score: 0.5. The value of ΔR, which is the expected score minus the result (in the case of a draw, 0.5) is therefore 0.5-0.5=0, i.e. no change in rating.

If instead their difference were 4 points rather than 3 (meaning that Carlsen's expected score would be 0.51 instead of 0.5), a draw would mean that his ΔR would be -0.01. With a K value of 10 (as he has a rating above 2400), his gain/loss would therefore be -0.01*10. In other words, a draw with a rating difference of 4 would mean that he would lose 0.1 rating point (whereas Caruana would gain 0.1 point).

  • 1
    If the ratings weren't that close, would they have changed already, or do they wait until the match is over? – itub Nov 14 '18 at 18:52
  • 3
    Officially, it's neither, as FIDE only updates their ratings once a month (per their official rules). However, it is possible to calculate real-time ratings after each individual game, as in done by this site for example. – ATLPoly Nov 14 '18 at 19:37
1

FIDE apply a monthly update of rating but, during matches or tournaments, the ratings of participants it remains unchanged until the event is completed.

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