HOW THE WORLD RANKING LIST CALCULATES RANKINGS
John Smith plays Mark Jones in the Canary Islands Open, a class 6 event. Let's see how a single game affects each player's individual ranking.
On the World Ranking List, Smith's grade is 2200, and Jones's grade is 2100. In the internal system of the list, Smith's index is 120 and Jone's is 110.
Jones' Index = (2100-1000)/10 = 110
Using the following formula, we calculate the delta which will be different depending on who wins.
Keeping in mind that "diff" in the formula above is the winning player's index minus the loosing player's index, if Smith Wins, the delta is 2.32 ...
but if Jones Wins, the delta is 3.68.
if Smith wins the match the players new indices are as follows
Jones' new index: 110 -2.32 = 107.68
Their new internal grades are calculated using
Jones' new internal grade: (110 * 0.9) + (107.68 * 0.1) = 109.768
In order to get the published grade we must multiply the internal grade by 10 and add 1000.
Jones' new published grade = (109.768 * 10) + 1000 = 2097.68 ... 2098
But if Jones wins the match, the players' new Grades are calculated as follows:
Jones' new index: 110 + 3.68 = 113.68
Their new internal grades are:
Jones' new internal grade: (110 * 0.9) + (113.68 * 0.1) = 110.368
So their published grades are:
Jones' new published grade = (110.368 * 10) + 1000 = 2103.68 ... 2104
If the players were to play a second match after Jones' win then the calculations for Smith are performed using an old index of 116.32 and an old internal grade of 119.632
That's all there is to it. Now you can calculate your own WCF ranking after your important high-level international rules tournaments.
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