Jeff Sagarin

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Jeff Sagarin is an American sports statistician well-known for his development of a methodology for ranking and rating sports teams in a variety of sports. His ratings have been a regular feature in the USA Today sports sections since 1985, have been used by the NCAA Tournament Selection Committee to help determine the participants in the NCAA Men's Division I Basketball Championship tournament since 1984, and have been a part of the Bowl Championship Series since its inception.

1 Methodology
2 Justification
3 Background
4 External link

[edit] Methodology

Sagarin, like the developers of other sports rating systems, does not divulge the exact methodology behind his numbers. He offers two rating systems, each of which gives each team a certain number of points. One system, "Elo chess", is presumably based on the Elo rating system used internationally to rank chess players. This system uses only wins and losses, with no reference to the victory margin. The other system "Predictor", takes victory margin into account. For that system, the difference in two teams' rating scores is meant to predict the margin of victory for the stronger team on a neutral court. For both systems, teams gain higher ratings within the Sagarin system by winning games against stronger opponents, factoring in such things as home-field advantage. For the Predictor system, margin of victory (or defeat) factors in also, but a law of diminishing returns is applied. Therefore, a football team that wins a game by a margin of 7-6 is rewarded less than a team that defeats the same opponent under the same circumstances 21-7, but a team that wins a game by a margin of 35-0 receives similar ratings to a team that defeats the same opponent 70-0. This characteristic is positively regarded among many as it recognizes "comfortable" victories, yet reduces a team's incentive to run up the score.

[edit] Justification

Sagarin's ratings are particularly relevant in the world of American college football and basketball, where, with over 200 teams in NCAA Division I competition, there is no way a team can play against more than a small fraction of its competitors. Therefore, in determining the participants in championship games and tournaments, it is necessary to distinguish between teams that have compiled impressive win-loss records against strong competition and teams that have defeated weaker opponents.

In addition, sports rating systems are generally of great interest to gamblers.