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## Effective number of games

For each player, let be the number of tournament games the player has competed, or, for unrated players, the value assigned from Step 1 of the algorithm. Let be the player's pre-event rating, or, for unrated players, the imputed rating assigned from Step 1. Let

 (1)

Define the effective'' number of games, , to be the smaller of and . As a result of the formula, can be no larger than 50, and it will usually be less, especially for players who have not competed in many tournament games. Note that is a temporary variable in the computation and is not saved after an event is rated.

Example: Suppose a player's pre-event rating is based on games. Then according to the formula above,


N* = 50/sqrt(1 + (2200-1700)^2/100000) = 50/sqrt(3.5) = 26.7


Consequently, the value of is the smaller of and , which is therefore . So the effective number of games for the player in this example is .

Next: Special rating formula Up: Details of the Rating Previous: Details of the Rating
Mark Glickman
2004-09-22