The dominant method for determining the world chess rankings was developed by physics professor Arpad Elo. It is a high-level professional player who can create such a well-thought-out formula. Moreover, he was a productive worker in US Chess Federation.

USCF began using the new system in 1960. It replaced a proposal by Kenneth Harkness. Further spread around the world was not fast. After its appearance, FIDE looked closely at the statistics and their correctness for several years. Therefore, they began to use only in 1970.

Invented for a competition between two participants but is great for other sports. Perfectly takes into account points for soccer, tennis, baseball, and more. Esports projects also use this method. For example, PUBG implements slightly modified formulas due to the abundance of supplementary data. It was used in League of Legends but the project has expanded tenfold.

## Calculation principles

The rating difference is a guideline for the intended outcome. This approach confuses people who associate high scores with the absolute strength of a grandmaster. A player with a 100-point lead is expected to win more often. In this case, there should be five wins in eight confrontations. A 200 advantage means winning three out of four games.

True skill is taken into account as the average of a random performance variable. Elo suggested that it changes over time but not very quickly. Confirmation can only be victories, draws, and defeats of a sportsman.

This is what the formula for calculating the expected scores looks like:

EA = 1 / (1 + 10^((RB-RA)/400))

*E*** A **is the expected number of points that player A will score with opponent B

*R*** A** is the rating of chess master A

*R*** B **is the same but for B

The updated data of participant A is calculated by the formula:

RA’ = RA + K * (SA – EA)

** K** is a coefficient that takes into account a number of sportsmen from the rating Covers the strongest, slightly weaker, and newcomers

*S*** A** is the points actually scored by player A.

## World chess rankings in the Elo system

The data is entered into the rating of responsible organizations after all calculations. FIDE uses over ten categories to clearly show the strength of its members. Even the closest ranks have a noticeable difference in the skills of sportsmen. Therefore, they can be in one of them for a long time.

## Results

It is not known when new methods will appear and replace all existing ones. However, now Elo is the most advanced tool for determining world chess rankings. It is this system that penetrates into other types of competitions. Thanks to these calculations, incredible modern players were recognized.