One possible problem with the ratings program is that it is possible for the average rating to drift gradually over long periods of time. Indeed, ratings devaluation is a problem with many ratings systems. I have therefore been examining the average rating of all players over time, as devaluation seemed to affect earlier versions of the ratings program.

Below is a graph of the weighted mean over time for all rated players, for the top 10 players in the ratings, and for the player at the top of the ratings. (The weighting function is the reciprocal of the square of the uncertainty in player's rating). I judge the ratings produced by the current version of the program to be reasonably stable.

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