About the Ratings

The skill level ratings are based on a number scale ranging roughly from 2.0 (least likely to win any given match), through 6.5 (the most likely to win any given match). Thus, a player's rating represents his or her ability to win a given match, taking into account all factors, such as racquet skill, speed, strength, endurance, experience and mental toughness.

A player's initial rating is usually determined when a "verifier" certified by the USSRA observes the player during a sanctioned match (usually in exchange for a small fee) and assigns a rating based on certain predetermined criteria. (There are seven certified verifiers in the National Capital area.) However, because the number of certified verifiers is limited relative to the number of people participating in Washington area leagues, the NCSRA gives each new player a provisional rating after their first two matches based on the position they play. For example, in Div. 2, players in position #4 are assumed to have skills midway between 4.00 and 4.25 (the bottom 4th of the skill range for Div. 2).

After a player is rated, his or her rating is adjusted following each sanctioned match (in leagues and tournaments), using the USSRA adjustment formula, which is a variation of the ELO algorithm used by the National Chess Federation. Essentially, it is based on the probabilities of winning or losing a match.

All losses cause the loser's rating to drop and all wins cause the winner's rating to rise, and the boost in the winner's rating is always identical in magnitude to the drop in the loser's rating. However, the changes may be small. A higher rated player is expected to win against a lower rated player, so a win for the higher rated player may produce only a slight increase in his or her rating and a correspondingly small drop in the loser's rating. On the other hand, a win against a much higher rated player produces a large increase in the winner's rating, while the loser's rating drops a lot. If two players with identical ratings play each other, the winner's rating will go up 0.05 and the loser's will drop 0.05. The most any rating can change after a single match is 0.10.

The math behind the adjustment algorithm is as follows:

The following are sample adjustments if Player A beats Player B.

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