The Rolling Window Instead of a Season
A rolling window has one immediate consequence: a result is worth the same the week it happens as it is eleven months later, and then it is worth nothing. It does not decay gradually. It simply drops out when the anniversary of the event arrives, and the ranking recalculates without it. This makes the ranking a continuous measure with no off-season and no clean slate.
The second structural feature is a cap on how many tournaments count. Only a limited number of a player's best results contribute, which keeps the list comparable between someone who plays a heavy schedule and someone who plays sparingly. The marginal value of an extra small tournament falls to nothing once a player's countable slots are already filled with better results, which is why elite players are selective in a way that looks like indifference and is actually arithmetic.
