rockwellpc
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Re:Rating Question - 2005/11/04 07:16
have said, the overall expectancy Rp = 0.64 Note that Rp = 1 * Pw + 0.5 * Pd + 0 * Pl = Pw + 0.5 * Pd Where Pw is the probability of win, Pd is the probabilkity of draw and Pl is the probability of loss.
Note also that Pw + Pd + Pl = 1 as the three mutually exclusives results cover the spectrum of all possibilities, hence we have the system of equations
Pw + 0.5*Pd = 0.64 Pw + 0.5*Pd + Pl = 1
Unfortunately we have three unknowns and only two equations. What we are missing is really critical statistical info on the ratio between wins and draws. As it happens, this ratio does not merely depend on the rating difference, but also on the ratings themselves in absolute terms (draws occur more often among higher rated people separated by 100 rating points than on lower rated people separated by 100 points) and on the time control! Statistician Jeff Sonas (you know him from Chessmetrics) addresses the issue in passing in a brief expos? which you can visit at: http://www.kasparov.com/serve/templates/folders/show.asp?p_docID=2101... Lang=EN
He states in relevant part (while talking about rapid tiebreaks) that [...] switching the time controls from classical to rapid, has about the same effect (on the frequency of draws) as changing one of the players from Peter Leko to either Veselin Topalov or Alexei Shirov, or changing the opening from a 1.d4 game to a Sicilian Dragon. Further, switching the time controls from classical to blitz, has about the same effect (on the frequency of draws) as changing a Peter Leko-Anatoly Karpov matchup into an Alexander Morozevich-Alexei Fedorov matchup, or changing a Petroff`s Defense into a King`s Gambit. This will indeed make the results slightly more random, which (as I said) could be addressed by making the rapid tiebreaks longer.
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When you appeal to force, there's one thing you must never do - lose.
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