Ratings System Explanation | Download Ratings List
The USATT Ratings Processing System
Tournaments are processed in chronological order. Late reporting tournaments, will be processed in chronological order regardless of when they are received.
Rating points are gained / lost by winning and losing matches in overall tournament results.
If a player defeats many opponents with a higher rating, their rating may be adjusted upwards and the tournament reprocessed with this higher rating. This is done to protect the ratings of players who have lost matches to a player who began the competition severely underrated and who demonstrates a consistent playing level far above the rating with which that player entered the competition.
Each new member is assigned a rating based on results from their first tournament. The more matches that are reported, the more accurate the initial rating will be. The Initial Rating calculation is described in Step 2, below.
Rating calculations: Points are gained and lost according to the rating difference between their two players by the following chart.
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Rating Chart |
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Point Spread
Between Players
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Expected Result
(Higher Rated Player Wins: number of points exchanged)
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Upset Result
(Lower Rated Player Wins: number of points exchanged)
|
|
0 - 12 |
8 |
8 |
|
13 - 37 |
7 |
10 |
|
38 - 62 |
6 |
13 |
|
63 - 87 |
5 |
16 |
|
88 - 112 |
4 |
20 |
|
113 - 137 |
3 |
25 |
|
138 - 162 |
2 |
30 |
|
163 - 187 |
2 |
35 |
|
188 - 212 |
1 |
40 |
|
213 - 237 |
1 |
45 |
|
238 and up |
0 |
50 |
Step 1: Find players that should be adjusted.
Based on results against other rated players in the tournament, a determination is made as to whether that player should have their rating adjusted upwards. The Adjusted Rating is derived by either a mathematical calculation, or a fixed rating assigned by either the Tournament Director, or USATT office.
There are two tiers of ratings adjustments that are used to derive at a player's adjusted rating.
The first tier is for players with a net "ratings point" gain between 50 and 74 points. The player's adjusted rating will be equal to their pre-tournament rating plus the net ratings gain. For example, if a player has a rating of 1440 and has a net ratings gain of 54 points, their adjusted rating will be 1494. The first tier is referred to as PASS1.
The second tier is used only for those rated players who have experienced a rating change of at least 75 for a particular tournament. The second tier is referred to as PASS2, and works as follows:
- If a player has either, all wins, or all losses, the Adjusted Rating is derived by taking the median implied rating for all of the player’s games. The implied rating is calculated using each of the opponents’ Pre-Tournament Ratings, and the Rating Chart above.
- If the player has wins and losses, the Adjusted Rating is derived by taking the average of the player’s Pre-Tournament Rating, and the average of the player’s best win and worst loss.
- In both cases, the player’s Adjusted Rating will never be lower than the player’s Pre-Tournament Rating. In the event that the PASS2 adjusted rating results in a lower rating than the player's Pre-Tournament Rating, the adjustment will then revert to the PASS1 adjusted rating, which is derived solely on the basis on net ratings point gain plus the player's pre-tournament rating.
Step 2: Find unrated player initial ratings.
Based on results against rated players in the tournament (including the adjusted ratings calculated in step 1), initial ratings are calculated for all unrated players. The Adjusted Rating (Initial Rating) for unrated players is derived by either a mathematical calculation, or a fixed rating assigned by either the Tournament Director, or USATT office. The mathematical calculation for unrated players works as follows:
- If the player has either, all wins, or all losses, the Adjusted Rating is derived by taking the median implied rating for all of the player’s games. The implied rating is calculated using each of the opponents’ Pre-Tournament Ratings, and the Rating Chart above. For players with all losses, the Adjusted Rating cannot be higher than the player’s worst loss.
- If the player has wins and losses, the Adjusted Rating is derived by taking the average of the player’s best win and worst loss.
- In both cases, the Adjusted Ratings for unrated players is subject to a 75 minimum value.
Step 3: Find final adjusted ratings.
Similar to step 1 except that player adjustments are based both on results against previously rated players as well as unrated players (using the ratings set in step 2). The adjusted ratings found in this step will be used for the final calculation of points won/lost for the tournament.
Step 4: Final ratings.
Total points won/lost will be calculated for each player based on the ratings chart. Players with adjusted ratings from step 3 will start step 4 with this rating and will gain/lose points based on this new rating.
When a late reporting tournament is processed, all the subsequent tournament results are recalculated as well, so that a player’s ratings history is always correct to that point.
A complete record of all tournament results is stored within the database. This allows for match corrections to be made. Sometimes players incorrectly indicate the winner/loser of a match in their paperwork to the Tournament Director. Sometimes a Tournament Director will incorrectly report a result to USA Table Tennis. Sometimes there will be a data entry error and show an incorrect result.
If you believe an incorrect result has been processed for one of your matches, you can report it by on this page. If an error is verified, the results are corrected and reprocessed for rating. No changes will be made to tournaments that are more than 60 days old.