Ranglisten > Hinweise zum Ranglistensystem > Punkteänderungen (Beispiele)
Nachfolgend einige Beispiele für Punktegewinne und Punkteverluste in Abhängigkeit von den Punkten (Ratings) und Standardabweichungen (SD) der Gegner mit englischen Kommentaren (Quelle):
The VATTA is using the Marcus Rating System which was developed with the help of a grant from the US Olympic Committee and was recently featured in the Journal of the Royal Statistical Society: Series D (The Statistician), 2001, vol. 50, part 2, pp. 191-208. Like other new systems, it sometimes take a little time to become comfortable with it, but understanding the basic logic behind the system should speed up this process.
The system is not a magical black box, just a statistically sound algorithm based on probability that treats every player fairly regardless of level of play and level of activity. Here are three charts that show how ratings under the system will change, along with some commentary to help you better understand what the system is doing.
Sample Rating Changes
| Both Player's Ratings | Both Player's SD | Winner's New Rating (SD in parentheses) | Loser's New Rating (SD in parentheses) |
| 1500 | 25 | 1504 (25) | 1496 (25) |
| 1500 | 50 | 1515 (48) | 1485 (48) |
| 1500 | 75 | 1529 (69) | 1471 (69) |
| 1500 | 100 | 1544 (90) | 1456 (90) |
| 1500 | 150 | 1574 (131) | 1426 (131) |
| 1500 | 200 | 1604 (171) | 1396 (171) |
| 1500 | 250 | 1634 (211) | 1366 (211) |
| 1500 | 300 | 1663 (252) | 1337 (252) |
In the above table, both players have the same initial rating and initial SD. The lower a player's SD, the more accurate their rating is. Therefore the point exchange between players will be smaller in matches involving players with lower SDs. The lower your SD, the more stable your rating is.
| Same Rating | Player with lower SD wins | Player with higher SD wins | |||
| Player 1 | Player 2 | Winner's New Rating | Loser's New Rating | Winner's New Rating | Loser's New Rating |
| 1500 (25) | 1500 (25) | 1504 (25) | 1496 (25) | 1504 (25) | 1496 (25) |
| 1500 (25) | 1500 (50) | 1504 (25) | 1484(47) | 1516 (47) | 1496 (25) |
| 1500 (25) | 1500 (75) | 1504 (25) | 1467 (68) | 1533 (68) | 1496 (25) |
| 1500 (25) | 1500 (100) | 1503 (25) | 1448 (85) | 1552 (85) | 1497 (25) |
| 1500 (25) | 1500 (150) | 1503 (25) | 1406 (117) | 1594 (117) | 1497 (25) |
| 1500 (25) | 1500 (200) | 1502 (25) | 1363 (146) | 1637 (146) | 1498 (25) |
| 1500 (25) | 1500 (250) | 1502 (25) | 1321 (174) | 1679 (174) | 1498 (25) |
| 1500 (25) | 1500 (300) | 1502 (25) | 1278 (202) | 1722 (202) | 1498 (25) |
In the above table, both players have the same initial rating, but vastly different SDs. Therefore the player's rating in the first column is more accurate than the player's rating in the second column since the former has a lower SD. You see that the player in column one is protected from losing large numbers of points while their opponent with a higher SD has the opportunity to gain or loss more points while lowering their SD at the same time.
| Same SD | Player with higher rating wins | Player with lower rating wins | |||
| Player 1 | Player 2 | Winner's New Rating | Loser's New Rating | Winner's New Rating | Loser's New Rating |
| 1500 (50) | 1500 (50) | 1515 (48) | 1485 (48) | 1515 (48) | 1485 (48) |
| 1525 (50) | 1500 (50) | 1538 (48) | 1487 (48) | 1517 (48) | 1508 (48) |
| 1550 (50) | 1500 (50) | 1561 (48) | 1489 (48) | 1520 (48) | 1530 (48) |
| 1600 (50) | 1500 (50) | 1607 (48) | 1493 (48) | 1524 (48) | 1576 (48) |
| 1700 (50) | 1500 (50) | 1703 (49) | 1497 (49) | 1532 (49) | 1668 (49) |
| 1800 (50) | 1500 (50) | 1801 (50) | 1499 (50) | 1535 (50) | 1765 (50) |
| 1900 (50) | 1500 (50) | 1900 (50) | 1500 (50) | 1537 (50) | 1863 (50) |
| Effect of Changing the SD | |||||
| 1900 (40) | 1500 (40) | 1900 (40) | 1500 (40) | 1524 (40) | 1876 (40) |
| 1900 (30) | 1500 (30) | 1900 (30) | 1500 (30) | 1513 (30) | 1887 (30) |
| 1900 (20) | 1500 (20) | 1900 (20) | 1500 (20) | 1506 (20) | 1894 (20) |
In the above table, the players have different initial ratings, but the same SDs. Therefore the two players have equally accurate ratings. We see that they exchange an equal number of points from each match.
Final thoughts - The goal of any rating system should be to accurately and fairly rate all players based on their tournament results. If you are not that familiar with the inner workings of the present USATT rating system, then you may not realize that while the system does a good job overall, it is far from perfect. The Marcus system is a very significant improvement over the current USATT rating system that produces more accurate ratings while treating all players fairly and impartially.