Kenneth Massey
Encyclopedia
Kenneth Massey is an American
sports statistic
ian known for his development of a methodology for ranking and rating sports teams in a variety of sports. His ratings have been a part of the Bowl Championship Series
since the 1999 season.
s, gives quite a lot of information on how his system works, but omits enough details to prevent someone from copying the calculations in their entirety. The Massey Ratings are designed to measure past performance, not necessarily to predict future outcomes. The first challenge for any computer rating system is to account for the variability in performance. A team will not always play up to its full potential. Other random factors (officiating, bounce of the ball) may also affect the outcome of a game. The model must somehow eliminate the "noise" which obscures the true strength of a team. The second goal is to account for the differences in schedule. When there is a large disparity in schedule strength, win-loss records lose their significance. The model must evaluate games involving mismatched opponents, as well as contests between well matched teams. It is necessary to achieve a reasonable balance between rewarding teams for wins, convincing wins, and playing a tough schedule. This issue is difficult to resolve, and rating systems exist that are based on each of the extremes.The overall team rating is a merit based quantity, and is the result of applying a Bayesian
win-loss correction to the power rating. Only the score, venue, and date of each game are used to calculate the Massey ratings. Stats such as rushing yards, rebounds, or field-goal percentage are not included. Nor are game conditions such as weather, crowd noise, day/night, or grass/artificial turf
. Overtime games are not treated any differently. Finally, neither injuries nor psychological factors like motivation are considered.
college football
, where, with over 100 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. Massey's ratings have come under some scrutiny as of late 2008 due to his controversial rankings at the end of the season. Although Massey's rating system came under fire near the end of the 2008 season for rating undefeated Utah ahead of then consensus human-poll #1 Alabama, his ratings seemed to be justified following Utah's 31-17 one-sided victory in the 2009 Sugar Bowl.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
sports statistic
Statistic
A statistic is a single measure of some attribute of a sample . It is calculated by applying a function to the values of the items comprising the sample which are known together as a set of data.More formally, statistical theory defines a statistic as a function of a sample where the function...
ian known for his development of a methodology for ranking and rating sports teams in a variety of sports. His ratings have been a part of the Bowl Championship Series
Bowl Championship Series
The Bowl Championship Series is a selection system that creates five bowl match-ups involving ten of the top ranked teams in the NCAA Division I Football Bowl Subdivision , including an opportunity for the top two to compete in the BCS National Championship Game.The BCS relies on a combination of...
since the 1999 season.
Methodology
Massey, unlike the developers of other sports rating systemSports rating system
A sports rating system is a system that analyzes the results of sports competitions to provide objective ratings for each team or player. Rankings are then derived by sorting each team's ratings and assigning an ordinal rank to each team starting with the highest rated team earning the #1 rank...
s, gives quite a lot of information on how his system works, but omits enough details to prevent someone from copying the calculations in their entirety. The Massey Ratings are designed to measure past performance, not necessarily to predict future outcomes. The first challenge for any computer rating system is to account for the variability in performance. A team will not always play up to its full potential. Other random factors (officiating, bounce of the ball) may also affect the outcome of a game. The model must somehow eliminate the "noise" which obscures the true strength of a team. The second goal is to account for the differences in schedule. When there is a large disparity in schedule strength, win-loss records lose their significance. The model must evaluate games involving mismatched opponents, as well as contests between well matched teams. It is necessary to achieve a reasonable balance between rewarding teams for wins, convincing wins, and playing a tough schedule. This issue is difficult to resolve, and rating systems exist that are based on each of the extremes.The overall team rating is a merit based quantity, and is the result of applying a Bayesian
Bayesian probability
Bayesian probability is one of the different interpretations of the concept of probability and belongs to the category of evidential probabilities. The Bayesian interpretation of probability can be seen as an extension of logic that enables reasoning with propositions, whose truth or falsity is...
win-loss correction to the power rating. Only the score, venue, and date of each game are used to calculate the Massey ratings. Stats such as rushing yards, rebounds, or field-goal percentage are not included. Nor are game conditions such as weather, crowd noise, day/night, or grass/artificial turf
Artificial turf
Artificial turf is a surface manufactured from synthetic fibers made to look like natural grass. It is most often used in arenas for sports that were originally or are normally played on grass. However, it is now being used on residential lawns and commercial applications as well...
. Overtime games are not treated any differently. Finally, neither injuries nor psychological factors like motivation are considered.
Justification
Massey's ratings are particularly relevant in the world of AmericanUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
college football
American football
American football is a sport played between two teams of eleven with the objective of scoring points by advancing the ball into the opposing team's end zone. Known in the United States simply as football, it may also be referred to informally as gridiron football. The ball can be advanced by...
, where, with over 100 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. Massey's ratings have come under some scrutiny as of late 2008 due to his controversial rankings at the end of the season. Although Massey's rating system came under fire near the end of the 2008 season for rating undefeated Utah ahead of then consensus human-poll #1 Alabama, his ratings seemed to be justified following Utah's 31-17 one-sided victory in the 2009 Sugar Bowl.
External links
- http://masseyratings.com/ Massey Ratings Website
- http://www.highschoolsports.net/masseyratings/ Massey Ratings on HighSchoolSports.net
- http://www.cn.edu/math/faculty.htm?#1768669890
- http://www.masseyratings.com/rate.php?lg=brfa