Page 1 of 1
Carlsen's Rating Requirement to be World No.1
Posted: Fri Dec 04, 2009 11:11 am
by John Saunders
I've been asked the question "What does Carlsen need to score in London to continue his current 0.4 points lead over Topalov in the daily live ratings into the January Fide list?" The questioner thought the answer was 5.5/7 or 5/7, but wasn't sure. Neither am I. Can anyone enlighten us?
Re: Carlsen's Rating Requirement to be World No.1
Posted: Fri Dec 04, 2009 12:40 pm
by Roger de Coverly
If I've reversed engineered the FIDE rating calculation correctly, then the required result is 5/7. "Proof" follows:-
Against Kramnik, Carlsen has a rating advantage of 29 - expected score 0.54.
Against the rest of the field
Nakamura 86 0.62
Short 94 0.63
Adams 103 0.64
Hua 136 0.68
McShane 186 0.74
Howell 204 0.76
This sums to 4.61 which means he needs 5 points to improve his rating by 3.9 points or 8.9 if gets 5.5
Re: Carlsen's Rating Requirement to be World No.1
Posted: Fri Dec 04, 2009 7:33 pm
by John Saunders
Many thanks for working that out, Roger. Much appreciated.
Re: Carlsen's Rating Requirement to be World No.1
Posted: Sun Dec 06, 2009 3:26 am
by Ian Thompson
Roger de Coverly wrote:If I've reversed engineered the FIDE rating calculation correctly, then the required result is 5/7.
...
This sums to 4.61 which means he needs 5 points to improve his rating by 3.9 points or 8.9 if gets 5.5
The live ratings say Carlsen is currently 2805.7 and Topalov 2805.1.
Accepting your arithmetic, if Carlsen only scores 4.5 points, then he'll lose 1.1 rating points, which will bring his rating down to 2804.6. This will get rounded up to 2805 in the FIDE list, making him equal with Topalov. Carlsen will be No.1 because he's played more games.