connors@drutx.UUCP (ConnorsPA) (12/11/85)
[] The system used to rate tournament chess was invented by Elo in 1959/1960. It was first used by the USCF in 1960, and was adopted in 1970 by FIDE for international ratings. The USSR is just now starting to use this system. It is based on statistical probability theory, with ratings following a Normal distribution with a mean of 1500 and a standard deviation of 200. Roughly speaking: 2700+ Kasparov, Karpov, etc. ( None active in the US. Unless Fischer.....) 2500+ Grandmaster strength (48 in the US) 2400+ International Master strength (76 in the US) 2200+ National Master (642 in the US) 2000+ Expert (2324 in the US) 1500+ Better than average. (Total of 15,000 in the US) Using the properties of the Normal distribution you can estimate the probable outcome of various tournament games. For example: 1) Kasparov (2715) versus Grandmaster (2500) Kasparov wins 3 out of 4. 2) Kasparov versus International Master (2400): Kasparov wins 17 out of 20. 3) Kasparov versus Expert (2000): Kasparov drops 1 game in 200. 4) Kasparov versus Average player (1500): Average player won't win unless Kasparov dies in mid-game, thus losing on time. Interestingly, this rating system is quite capable of being applied to other sports, especially where the competition is of an individual or one-on-one nature. We could find out exactly how good John McInroe is at tennis, or Arnold Palmer at golf. Paul Connors Email: ihnp4!drutx!connors Phone: (303)-538-4047
glickman@fisher.UUCP (Mark E. Glickman) (12/11/85)
> It is based on statistical probability theory, with > ratings following a Normal distribution with a > mean of 1500 and a standard deviation of 200. Well, not quite. The rating system is very much skewed to the left - there is a very high concentration of lower rated players (that are incidentally, for the most part, inactive) that cause the distribution to demonstrate assymetry. A player's performance, however, is asymptotically normally distributed. - Mark Glickman (member of the USCF Rating Committee)