Arpad Emre Elö was born 100 years ago (on August 25, 1903) in Hungary. His family were farmers who moved to Cleveland, USA, in 1913. After finishing school he studied physics at the University of Chicago and went on to teach the subject until his retirement in 1969, after which he taught it on a part-time basis. The orthography of his name changed from Elö to Elo.

Young Arpad learnt chess at the age of ten, and the game became one of his many lifetime hobbies (including wine-making, horticulture, astronomy and music). He achieved a very respectable playing strength, winning the Wisconsin state championship eight times. His chess record includes over forty tournament wins, with two drawn games against Rueben Fine. He was elected president of the American Chess Federation in 1935 and was one of the founders of the USCF in 1939.

In 1959 the USCF asked Arpad Elo to improve the chess rating system used in the US chess community. This was not very accurate and contained some serious problems. For instance it was possible for players to gain points in spite of losing every game in a tournament, and to lose points after winning them all. There were other rating systems, like the Ingo system that was popular in Europe (on it's 1-200 rating scale strong players had lower numbers).

Elo proposed a new system with a statistically sound basis based on the bell curve. Elo's formula assumed that the performance of a player is normally distributed. He used rating numbers that were similar to those players were using at the time, so that people would not have to get used to completely different numbers. According to this system an average player was rated 1500, a strong club player 2000 and a grandmaster 2500.

Professor Elo's rating system was adopted by the USCF in 1960 and by FIDE in 1970. The system was designed to be simple enough to calculate with pencil and paper, but when the first pocket calculators appeared, Elo started to compile the official FIDE ratings on an Hewlett-Packard calculator.

The World Chess Hall of Fame writes: "Professor Elo's creativity, integrity and statistical skill earned him respect not just nationally but internationally. In his capacity as chairman of the FIDE Qualifications committee, for at least fifteen years, he was responsible for seeing that players who deserved international titles received them, and those whose demonstrated strength did not prove they merited an international title did not receive them."

Elo was always careful to keep the value of his invention in perspective, and in a 1962 Chess Life article, he came up with a memorable analogy to describe the difficulty of accurately measuring playing strength: "Often people who are not familiar with the nature and limitations of statistical methods tend to expect too much of the rating system. Ratings provide merely a comparison of performances, no more and no less. The measurement of the performance of an individual is always made relative to the performance of his competitors and both the performance of the player and of his opponents are subject to much the same random fluctuations. The measurement of the rating of an individual might well be compared with the measurement of the position of a cork bobbing up and down on the surface of agitated water with a yard stick tied to a rope and which is swaying in the wind."

Rating of Chessplayers Past and Present

In 1978 Elo published a book entitled "The Rating of Chessplayers, Past and Present" which contained the historical ratings of 476 chess players. In this list Capablanca is the strongest player of all time, rated at 2725, Paul Morphy ranks sixth at 2690. The ratings are five-year peak averages. Fischer and Karpov were at the top of the list, although they were 2780 and 2775 on the January 1st 1978 FIDE ratings list, since these numbers did not represent a five-year average for the players.

Links

• Arpad Elo, Father of Scientific Chess Ratings
• Milwaukee Chess History: Arpad Elo
• The Legacy of Arpad Elo (PDF file)
• The Sonas Rating Formula
• Some remarks on Jeff Sonas' article
• Championship Chessmetrics Analysis
• FIDE Rapid Ratings

  Frederic Friedel