Ratings Calculation Question
Posted:
Sep 23, 2006, 12:22 AM
If you begin a rated game with someone, and their rating changes midway through the game from a different game they were playing at the same time, are the post-game ratings changes calculated from that person's rating at the start of the game, or their current rating?
Without actually checking the code I'm 99% certain the rating used to calculate the change is the current rating, not the rating as it was at the start of the game.
I don't see how you could argue that the rating at the beginning of the game is somehow "better" to use than the current rating....not that you are but just saying .
well like say you start a game with some one rated 1700. you go in with the expectation that your rating will change based on their 1700 rating. if midway through the game your opponent loses 50 points (unlikely i know, but that's just one set against a low rated opponent, very plausible), all of a sudden your rating is calculated against a 1650 opponent instead of a 1700 opponent. not much of a difference in the long run, but interesting to consider.
this will happen more often with turn-based games, i had thought about that case some earlier, there might even be a discussion of it in the turn-based forums.
the opposite scenario is you invite a player with a 1700 rating to a turn-based game, they lose a bunch of games before they start your game and DSG records their rating to use as 1500. By the time your set is complete their rating is back at 1700, but the rating calculation will use 1500.
its my opinion that the above scenario is no better than what DSG does now. there is really no good answer but i think that using the most current rating of a player makes sense, you are basing the rating change on the most accurate rating that you have on a player (since the ratings are the most current).
of course the really hard part of doing what you suggest is handling the switch from provisional to established, it becomes pretty much impossible to do in a good way.
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