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Ratings structure
All these ratings evaluate every day all bouts in the database in chronological sequence. A higher rated boxer should be expected to defeat a lower rated boxer with increasing probability by increasing rating difference.
Current ("Active") rating
1. Every boxer gets a first rating of 0 before his first bout.
2. After every bout, the ratings of the two boxers involved are changed depending on the bout's official result (KO, TKO, RTD, UD, PTS, NWS, MD, SD, DQ, TD, DRAW).
3. The value of a result varies between v=1 and v=0.
4. The clear decision factor varies between cd=1 and cd=0.
5. The winner cannot lose points for KO, TKO, RTD, DQ, TD and decisions on points with cd=1
6. KO, TKO, RTD are rewarded with full value v=1, cd=1.
7. NWS is rewarded with full value v=1 for 12 rounds boxed and more and a lower value related to the number of rounds boxed. Clear decision factor cd=1.
8. UD, PTS are rewarded with full value v=1 for 12 rounds boxed and more and a lower value related to the number of rounds boxed, clear decision factor cd=1. This is valid, if the score cards are not available.
9. DRAW is rewarded with full value v=1 for 12 rounds boxed and more and a lower value related to the number of rounds boxed. Clear decision factor cd=0.
10. MD, SD, DQ, TD are rewarded with full value v=1 for 12 rounds boxed and more and a lower value related to the number of rounds boxed. Clear decision factor cd=0.5. This is valid, if the score cards are not available.
11. If the score cards are available, the value rewarded is in relation to the rounds boxed, with full value v=1 for 12 rounds boxed and more. The clear decision factor is in proportion to rounds boxed and the mean score difference per judge. cd=1 for mean score difference divided by a sixth of rounds boxed greater or equal 1.
12. All bouts are regarded to have the same weight independent of titles.
13. The winner gets a certain part of the opponent's points and a certain part of the rating difference to the opponent's rating.
14. The winner gets at maximum 50 additional points. The 50 additional points are reduced by half the rating difference between the winner and the loser and by half of the own rating. The maximum of 50 points is only awarded, if the defeated opponent has 5 wins at minimum. In other cases the amount is reduced in relation to the number of wins.
15. For a DRAW the rating of the higher rated boxer is reduced by some part of the point difference; the rating of the lower rated boxer is enhanced by the same amount of points.
16. The full relative point reward is 33%. It is in relation to the pre-bout rating of the defeated opponent.
17. The ratings are decreased for moving up to higher weight divisions by the square of the reciprocal ratio of the weights limits of the divisions--and they are increased by the same factor for moving down the divisions.
18. The ratings are equalized between division clusters in relation to average points of the boxers ranked #8, #9, #10, #11 and #12 in a division cluster. The division clusters are heavyweight including cruiserweight, light heavyweight indluding super middleweight, middleweight indcluding light middleweight, welterweight including light welterweight, lightweight including super featherweight, featherweight including super bantamweight, bantamweight including super flyweight and flyweight including light flyweight an minimumweight.
19. The rating of a boxer is reduced by 0% to 50%, if he didn't box an opponent with a rating of at least 50% to 0% of his own rating points within 18 months.
20. The rating of a boxer is reduced by 50% for every time period of inactivity of 18 months.
21. The pre-bout rating of a boxer successfully returning from inactivity is set to the lower value of his opponents pre-bout rating and his own rating before inactivity.
22. The pre-bout rating of a successfully debuting boxer is set to 25% of his opponents pre-bout rating.
Formula
If a boxer with a rating of r_a before the fight defeats a boxer b with a rating of r_b before the fight with result of value v and clear decision factor cd, the new ratings new_a and new_b after a fight are, earn_f is 33.3%:
* earn= earn_f * v * ($r_b*cd + (r_b-r_a)/(1+2*cd));
* new_a= r_a + earn;
* new_b= r_b - earn;
Examples
Boxer a KO boxer b, a has 1000 points, b has 500 points. v=1, cd=1
* earn= 0.33 * 1 * (500*1 + (500-1000)/(1+2*1)) = 111
* r_a_new = 1000 + 111 = 1111
* r_b_new = 500 - 111 = 389
Boxer a UD 6 boxer b, scores 59:55 58:56 58:56, a has 1000 points, b has 500 points.
* A 6 rounder is rewarded with value 6/12, v=0.5
* UD is rewarded with cd=1 at maximum
* mean score difference per judge is (4+2+2)/3 = 2.667, which is rewarded in relation to half the rounds boxed with cd= 2.667/3 = 0.89 at maximum
* so cd=0.89
* earn= 0.33 * 0.5 * (500*0.89 + (500-1000)/(1+2*0.89)) = 44
* r_a_new = 1000 + 44 = 1044
* r_b_new = 500 - 44 = 456
Boxer a SD 4 boxer b, scores 39:37 39:37 37:39, a has 1000 points, b has 500 points
* A 4 rounder is rewarded with 4/12, v=0.333
* SD is rewarded with cd=0.5 at maximum
* mean score difference per judge is (2+2-2)/3 = 0.667, which is rewarded in relation to half the rounds boxed 0.667/2 at maximum\
* so cd=0.333
* earn= 0.33 * 0.33 * (500*0.33 + (500-1000)/(1+2*0.33)) = -15
* r_a_new = 1000 - 15 = 985
* r_b_new = 500 + 15 = 515
http://boxrec.com/media/index.php/Ratings
All these ratings evaluate every day all bouts in the database in chronological sequence. A higher rated boxer should be expected to defeat a lower rated boxer with increasing probability by increasing rating difference.
Current ("Active") rating
1. Every boxer gets a first rating of 0 before his first bout.
2. After every bout, the ratings of the two boxers involved are changed depending on the bout's official result (KO, TKO, RTD, UD, PTS, NWS, MD, SD, DQ, TD, DRAW).
3. The value of a result varies between v=1 and v=0.
4. The clear decision factor varies between cd=1 and cd=0.
5. The winner cannot lose points for KO, TKO, RTD, DQ, TD and decisions on points with cd=1
6. KO, TKO, RTD are rewarded with full value v=1, cd=1.
7. NWS is rewarded with full value v=1 for 12 rounds boxed and more and a lower value related to the number of rounds boxed. Clear decision factor cd=1.
8. UD, PTS are rewarded with full value v=1 for 12 rounds boxed and more and a lower value related to the number of rounds boxed, clear decision factor cd=1. This is valid, if the score cards are not available.
9. DRAW is rewarded with full value v=1 for 12 rounds boxed and more and a lower value related to the number of rounds boxed. Clear decision factor cd=0.
10. MD, SD, DQ, TD are rewarded with full value v=1 for 12 rounds boxed and more and a lower value related to the number of rounds boxed. Clear decision factor cd=0.5. This is valid, if the score cards are not available.
11. If the score cards are available, the value rewarded is in relation to the rounds boxed, with full value v=1 for 12 rounds boxed and more. The clear decision factor is in proportion to rounds boxed and the mean score difference per judge. cd=1 for mean score difference divided by a sixth of rounds boxed greater or equal 1.
12. All bouts are regarded to have the same weight independent of titles.
13. The winner gets a certain part of the opponent's points and a certain part of the rating difference to the opponent's rating.
14. The winner gets at maximum 50 additional points. The 50 additional points are reduced by half the rating difference between the winner and the loser and by half of the own rating. The maximum of 50 points is only awarded, if the defeated opponent has 5 wins at minimum. In other cases the amount is reduced in relation to the number of wins.
15. For a DRAW the rating of the higher rated boxer is reduced by some part of the point difference; the rating of the lower rated boxer is enhanced by the same amount of points.
16. The full relative point reward is 33%. It is in relation to the pre-bout rating of the defeated opponent.
17. The ratings are decreased for moving up to higher weight divisions by the square of the reciprocal ratio of the weights limits of the divisions--and they are increased by the same factor for moving down the divisions.
18. The ratings are equalized between division clusters in relation to average points of the boxers ranked #8, #9, #10, #11 and #12 in a division cluster. The division clusters are heavyweight including cruiserweight, light heavyweight indluding super middleweight, middleweight indcluding light middleweight, welterweight including light welterweight, lightweight including super featherweight, featherweight including super bantamweight, bantamweight including super flyweight and flyweight including light flyweight an minimumweight.
19. The rating of a boxer is reduced by 0% to 50%, if he didn't box an opponent with a rating of at least 50% to 0% of his own rating points within 18 months.
20. The rating of a boxer is reduced by 50% for every time period of inactivity of 18 months.
21. The pre-bout rating of a boxer successfully returning from inactivity is set to the lower value of his opponents pre-bout rating and his own rating before inactivity.
22. The pre-bout rating of a successfully debuting boxer is set to 25% of his opponents pre-bout rating.
Formula
If a boxer with a rating of r_a before the fight defeats a boxer b with a rating of r_b before the fight with result of value v and clear decision factor cd, the new ratings new_a and new_b after a fight are, earn_f is 33.3%:
* earn= earn_f * v * ($r_b*cd + (r_b-r_a)/(1+2*cd));
* new_a= r_a + earn;
* new_b= r_b - earn;
Examples
Boxer a KO boxer b, a has 1000 points, b has 500 points. v=1, cd=1
* earn= 0.33 * 1 * (500*1 + (500-1000)/(1+2*1)) = 111
* r_a_new = 1000 + 111 = 1111
* r_b_new = 500 - 111 = 389
Boxer a UD 6 boxer b, scores 59:55 58:56 58:56, a has 1000 points, b has 500 points.
* A 6 rounder is rewarded with value 6/12, v=0.5
* UD is rewarded with cd=1 at maximum
* mean score difference per judge is (4+2+2)/3 = 2.667, which is rewarded in relation to half the rounds boxed with cd= 2.667/3 = 0.89 at maximum
* so cd=0.89
* earn= 0.33 * 0.5 * (500*0.89 + (500-1000)/(1+2*0.89)) = 44
* r_a_new = 1000 + 44 = 1044
* r_b_new = 500 - 44 = 456
Boxer a SD 4 boxer b, scores 39:37 39:37 37:39, a has 1000 points, b has 500 points
* A 4 rounder is rewarded with 4/12, v=0.333
* SD is rewarded with cd=0.5 at maximum
* mean score difference per judge is (2+2-2)/3 = 0.667, which is rewarded in relation to half the rounds boxed 0.667/2 at maximum\
* so cd=0.333
* earn= 0.33 * 0.33 * (500*0.33 + (500-1000)/(1+2*0.33)) = -15
* r_a_new = 1000 - 15 = 985
* r_b_new = 500 + 15 = 515
http://boxrec.com/media/index.php/Ratings
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