Introduction
Boxing Record Archive (BoxRec.com) provides "Current" and "All-Time" boxer ratings. The "Current" ratings include only boxers who have been "active" (had a bout) within the past 365 days, or have a bout scheduled. Every active boxer in the database is rated--even those with an 0-1 record. (After one year, an active boxer automatically is designated "inactive" by the BoxRec computer.) The "All-Time" ratings include both "active" and "inactive" (i.e., retired) boxers.
The "Current" and "All-Time" ratings are wholly dependent upon the bouts contained in the database. They are not influenced by BoxRec's subjective views or by anyone else's opinions. A boxer may earn or lose ratings points with every bout he has; a boxer may also earn or lose points if bouts are added to any of his opponents' records, or to their opponents' records. The ratings are generated by the BoxRec computer, and are refreshed at approximately 9:35 GMT every day.
There are inaccuracies (especially lower down the ratings) because of incomplete records. However the ratings are continually improving as new bouts are entered into the database. (Presently, 2,000 to 3,000 recent and older bouts are entered each week by the BoxRec Editors.) Although a particular boxer’s own record may be complete, his opponents’ records are not always complete. Pre-World War II boxers are at somewhat of a disadvantage, vis-à-vis modern boxers. Their opponents’ records often are extremely incomplete, while the records of opponents of more current boxers often are quite complete. So, for example, while the records of Mike Tyson’s opponents may be quite complete--thereby earning Tyson a certain number of points and giving him a high ranking among the All-Time Heavyweights--the records of Young Stribling’s opponents may be extremely lacking, thereby giving Stribling fewer points and a much-lower All-Time rating. In fact, it may appear to the casual BoxRec visitor that Stribling had fought many boxers making their professional debuts, or having only two or three total career bouts. It’s just that not all of his opponents’ bouts have been found or entered yet. As the BoxRec Editors continue to research older resources and enter “new” historical bouts into the database, the rating of an old-time boxer like Stribling will gradually move up or down, even if his own record is complete--if bouts are added to his opponents’ records, or to his opponents' opponents' records, and so forth.
Further, because of the very few women presently boxing professionally, with some weight divisions having only a handful of active female boxers, a woman with an 0-1 record will appear “world ranked” by BoxRec. This is simply an anomaly due to the few female entries in the database.
Ratings structure
The current ratings consist of
a basic rating
a launching point system for not established boxers, not yet rated
All these ratings evaluate every day all bouts in the database in chronological sequence.
All parameter values are optimized to get best prediction quote of bout results in BoxRec database. So these ratings are optimized performance ratings. A higher rated boxer should be expected to defeat a lower rated boxer with increasing probability by increasing rating difference.
Current rating
The published current rating for established boxers is their basic rating
For not established boxers their launch points are published for reference
Launch points are 16 steps from 0 to 15 points
So everybody can clearly distinguish between established and not established boxers
Basic rating
Every boxer gets a first rating of 1,000 before his first bout.
After every bout the rating of the two boxers involved is changed depending on the bout's official result (KO, TKO, RTD, UD, PTS, NWS, MD, SD, DQ, D). TD is not regarded.
All bouts are regarded to have the same weight independent of titles.
The winner gets a basic gain / the loser a basic loss of points depending on the type of result.
This gain / loss is corrected by some amount depending on the difference between the ratings of the opponents before the bout. If the winner was rated higher than his opponent before the bout, his gain will be decreased. If his rating was lower, his gain will be increased. The loser's loss is handled in the same way.
A boxer is regarded to have an home advantage, if he has already fought a minimum of two bouts in the country where the current bout is taking place.
For Unanimous Decisions, Win on Points, Majority Decisions, and Split Decisions, the gain/loss will be calculated directly from the judges' scores, if available.
For a second and further win against a winless opponent, the boxer will only be rewarded 1 point.
The rating is reduced in proportion to a product of average rating difference to opponents, consequent number of no-losses and average bouts per period
The point gain is reduced to 50% if the performance for the current bout is smaller than for the bout before.
For TKO, KO and RTD the winner is rewarded 6 addtional points for a 1st round win, 5 for a 2nd round win, ... and 1 point for a 6th round win.
A winner's rating will not decrease, if the result was KO, TKO, RTD or DQ. The loser's will not increase in this case.
The ratings are decreased for moving up to higher weight divisions by some factor - and they are increased by some smaller factor for moving down the divisions. This factor depends on the the weight limits of the divisions.
All ratings are decreased by a small factor on a daily basis.
Parameter values
Home advantage = 125
TKO = 85
RTD = 85
KO = 80
UD = 80
PTS = 60
NWS = 60
MD = 50
SD = 50
DQ = 50
D = 0
SCORES for UD, PTS, MD, SD: 20 * mean score difference per judge; maximum 90
R_DIFF = correction for rating difference of opponents: 13.8 percent
DECAY = continuous rating decay of 8.7 percent/year on a daily basis
WEIGHT_UP: r_up = r*(weight_div/weight_div_up)**0.3
WEIGHT_DOWN: r_down = r*(weight_div/weight_div_down)**0.15
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 RES the new ratings r_a_new and r_b_new after a fight are:
r_a_new = r_a + RES + (r_b - r_a)*R_DIFF
r_b_new = r_b - RES + (r_a - r_b)*R_DIFF
Launch point system
Every boxer starts with 0 launch points before his first bout - this is grade 0.
A boxer gets 1 point for defeating an opponent of grade 0 to 2, this ends at a maximum of 3 points.
A boxer achieves grade 4 for defeating an opponent of grade 3 to 5.
A boxer then gets another point for defeating an opponent of grade 3 to 5, this ends at a maximum of 6 points.
A boxer achieves grade 7 for defeating an opponent of grade 6 to 8.
A boxer then gets another point for defeating an opponent of grade 6 to 8, this ends at a maximum of 9 points.
A boxer achieves grade 10 for defeating an opponent of grade 9 to 11.
A boxer then gets another point for defeating an opponent of grade 9 to 11, this ends at a maximum of 12 points.
A boxer achieves grade 13 for defeating an opponent of grade 12 to 14.
A boxer then gets another point for defeating an opponent of grade 12 to 14, this ends at a maximum of 15 points.
A boxer is launched and regarded as established and then has a regular rating, as soon as he defeated a boxer of grade 15 or an established boxer.
The loser is set back by 1 grade, if he loses to a boxer of lower grade.
An established boxer losing to a not established boxer is set back to grade 15 - he is unlaunched.
If the winner then has less launch points than his defeated opponent, his launch points will be set to his opponent's + 1
All time ratings
The all time ratings show the average of the best 5 annual ratings.
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explanation of how boxrec ratings work
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Originally Posted by SalTheButcher
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