AQB Sports Ratings

From Wikipedia, the free encyclopedia

The AQB Sports Ratings is a mathematical system for ranking sporting teams devised by Michael Cameron of the University of Waikato in New Zealand. The system is based on a relatively simple formula and can be used for a number of different sports. As of June 2006, AQB was ranking international cricket, rugby and association football national teams as well as the provincial Super 14 rugby tournament and the NFL American football.

[edit] How ratings are calculated

After each game in the relevant competition, each team's ratings are modified according to whether they won or not, whether they were playing at home or not, and the difference in each team's ratings prior to the game.

$R n = R o + R (B + H + D K)$

where:

R_n	is the new rating
R_o	is the old rating
R	is the result factor (+1 for a winning team, -1 for a losing team, +0.25 for a drawing team who started the game with a lower ranking, -0.25 for a drawing team who started the game with a higher ranking, and 0 for drawing teams who started with the same ranking)
B	is the base ratings change for any result, B=20
H	is the home advantage factor (+4 if the away team wins, -4 if the home team wins, and 0 for games played on a neutral ground)
D	is the points differential prior to the game (equal to the loser's original rating minus the winner's original rating; or in the case of the draw, the higher original rating minus the lower one
K	is a constant applied to weight the ratings, K=0.05