In matches where all players have previous ratings the procedure is as follows:
1. The system looks up the current dynamic rating of all the players in the match.
2. The system looks up from a table, the likely score of the match based on the current dynamics of the players.
3. The system compares the likely match score with the actual match score. For example, if one player or team has a tenth of a point higher rating than the opponent, the likely score is 6-4, 6-4.
- If the winning team wins by a larger than expected margin, each player’s ratings is increased based on the margin of victory and the losing player’s rating is decreased by the same amount.
- If the winning team wins by less than the expected margin, their ratings will actually decrease and the losing team’s ratings will increase.
- Likewise, the “wrong” team may win which causes their rating to increase markedly and the rating of the team which was favored would decrease by the same amount.
4. The rating obtained for each player in Step #3 is averaged with a maximum of their previous three dynamic ratings and that number becomes their new current dynamic rating. (Indirectly this connects the current dynamic to all previous matches but weights the four most recent matches more heavily.) The reason for this averaging is to even out the ratings in cases where some unusual situation causes an atypical result.
Each player rating is maintained in the system to the nearest hundredth of a point.
The difference in ratings of the members of a doubles team is held constant in a calculation of an individual match. If the two players are three hundredths (.03) of a point apart going into the match then they are three hundredths (.03) apart after the calculation in Step #4. However, once that number is averaged with the three previous dynamic ratings (Step #5) that difference may change. This is how we measure the performance of players as they change partners.