A few days ago, D Gukesh, part of the Indian team for the Olympiad, breached the Elo rating of 2700. Here's a brief explainer on how Elo came to being, why it's important and how some of us could have been rated according to this method because of its widespread use elsewhere.
What's the Elo rating method?
It's named after a Hungarian physician, Arpad Elo, who migrated to the US before the start of the first World War. Complex set of formulae is used to arrive at the Elo ratings of players. It was first adopted by the US Chess Federation in 1960 before FIDE (World Chess Federation) adopted it too. Most chess federations use the Elo method or a variation to rank players.
How did Gukesh raise his rating to 2700?
Gukesh beat fellow GM, Liem Le Quang, a higher rated player at the Biel Chess Festival in Switzerland. However, the very nature of Elo is it's very dynamic and it keeps changing on a per match basis. That's why Gukesh's live rating now stands at 2693.7.
What are the basic principles?
To put it in very simplistic terms, if a lower-ranked player were to beat a higher-ranked player, then the former's points would have a substantial jump as the odds of that happening are less when compared to the higher-ranked player beating a lower-ranked player.
Explain with an example
An example: Player A, with an Elo rating of 2400, faces player B, Elo rating of 2000. If the former beats the latter, it's insignificant so there will only be miniscule increase in Player A's rating. However if the opposite were to happen, Player B's rating would see a big jump. So if Player A were to win, their rating would increase to 2400, with Player B's rating dropping to 1997. But if Player B were to win, their rating would increase to 2029, with Player A's dropping to 2371. Mathematical formulae are used to arrive at these figures.
Why is this considered the gold standard for rating professional chess players?
Not just chess but in some zero-sum games (a principle in game theory where a player's winnings is directly balanced out by the losses of their opponent) Elo rating is considered as the gold standard. There is a belief that adopting such a system will mean players, over the long run, will always be rated according to their true level. Citing the above example, it's unlikely that Player A will keep losing to Player B. Also equally unlikely that Player B will keep beating Player A.
Where else is Elo rating used?
Video games like Age of Empires relied on Elo rating to mark the scores of the players. Then Tinder, the dating app, actually used to rate people by their 'attractiveness'. When more people swiped right, the 'attractiveness' rating would go up. In 2019, the company revealed that they don't do it anymore. "A few years ago, the idea of an “Elo score” was a hot topic among members and media alike. And sometimes, it still is. Here’s the scoop: Elo is old news at Tinder. It’s an outdated measure and our cutting-edge technology no longer relies on it."