The rating percentage index , commonly known as RPI, is the amount used to rank sports teams based on the team's victory and losses and the strength of the schedule. This is one of the sports assessment systems in which the NCAA basketball team, baseball, softball, hockey, soccer, lacrosse, and volleyball rankings. The system has been used in college basketball since 1981 to assist in selecting and sowing teams that appear in male playoffs (see March Madness), and for women tournaments since its birth in 1982.
In its current formulation, the index consists of the percentage of team victory (25%), the percentage of the victory of the opponent (50%), and the winning percentage of their opponent's opponent (25%). The percentage of the opponent's victory and the winning percentage of the opponent's opponent both consist of the power of the schedule (SOS). Thus, SOS accounts for 75% of RPI calculations and 2/3 percentage of opponent's and 1/3 opponents winning opponents' percentage wins.
The RPI has no theoretical justification from a statistical point of view. Other ratings systems that include game play margins or stats other than win/lose results have proven to be better predictors of future matches. However, since the margin of victory has been manipulated in the past by teams or individuals in the context of gambling, the RPI can be used to reduce the motivation of such manipulation.
Some people feel that the heavy emphasis on the power of the schedule provides an unfair advantage to the team from the main conference. Teams of "majors" are allowed to select many of their non-conference opponents (often very weak teams). But teams from small conferences may only get one or two such opponents in their schedules. Also, some major mid-term conferences regularly force their team members to schedule opponent ratings in the upper half of the RPI, which can increase the strength of the conference and/or a more rigorous scheduling team. In basketball, the Missouri Valley Conference has managed to do this: It has been one of the top-ranked RPI conferences, despite having very few of its teams ranked in two top 25 national polls. In 2006, the NCAA began releasing their RPI calculations every week starting in January. Independent sources, such as ESPN or CNN/SI, also publish their own RPI calculations, which are updated more frequently.
Video Rating percentage index
Rumus basket
The current and general formula used to determine the RPI of a college basketball team at a given time is as follows.
RPI = (WP * 0,25) (OWP * 0,50) (OOWP * 0,25)
in which WP Wins Percentage, OWP is the Opponent's Determining Percentage and OOWP is the Opposition Opponent's Opposent.
WP is calculated by taking a team win divided by the number of games that have been played (ie win plus loss).
For the NCAA Men's Basketball Division 1, the WP factor of the RPI was updated in 2004 to explain the differences in home, away, and neutral games. The home win now counts as a 0.6 victory, while the road win counts as 1.4 wins. In contrast, a home loss equals 1.4 losses, while road loss is calculated as 0.6 loss. Neutral match is considered as 1 victory or 1 defeat. This change is based on statistical data that consistently shows the home team in Division I basketball won about two thirds of the time. Note that this location adjustment only applies to WP factors and not OWP and OOWP factors. Only games against Division 1 teams are included for all RPI factors. For example, if the team loses to Syracuse at home, beat them, and then lose to Cincinnati, their record will be 1-2. Considering the weighted aspect of WP, their winning percentage is 1.4/(1.4 1.4 0.6) = 0.4118
OWP is calculated by taking the average WP for each team opponent with the requirement that all matches against the team in question be removed from the calculation. Continuing from the example above, assume Syracuse has played another game and lost, while Cincinnati has played two other teams and won. The team in question has played Syracuse twice and therefore Syracuse must be counted twice. So the OWP team is (0/1 0/1 2/2)/3 (count of opponents - Syracuse, Syracuse, Cincinnati). OWP = 0.3333
OOWP is calculated by taking the average of each Opponent OWP. Note that the team in question is part of the OOWP team. In fact, the most common opponent of your opponent is the team in question.
Continuing the example above, a team has played Syracuse twice and Cincinnati once. Syracuse has played another game and lost, while Cincinnati has played two other matches and won. Furthermore, for simplicity, assume none of the unnamed teams have played any other games.
The OOWP is calculated as (OWP Syracuse OWP Cincinnati OWP)/3.
Syracuse has played and defeated the team (which, excluding matches against Syracuse, only lost to Cincinnati), lost to the questionable team (except Syracuse, only lost to Cincinnati), and lost another game (except Syracuse, this team lacked WP). Syracuse's OWP is (0/1 0/1)/2 = 0,0000.
Cincinnati has played a questionable team (not including Cincinnati, they went 1-1 vs Syracuse) and won against two other opponents who each had no WP when the match versus Cincinnati was excluded. Cincinnati's OWP is (1/2)/1 = 0.5000.
For the team in question, the OOWP is thus (0,0000 0,0000 0,5000)/3 = 0.1667
For the team in question, the RPI can now be calculated:
RPI = (WP * 0,25) (OWP * 0,50) (OOWP * 0,25)
Entering a number from the example above gives you
RPI = (0.4117 * 0.25) (0.33333 * 0.50) (0.1667 * 0.25) = 0.3113
Additional examples
Assume the following game results:
Here are WP, OWP, and OOWP calculations for each team:
WP
- UConn: 3/4 = 0.7500 Weighted 2.6/3.2 = 0.8125
- Kansas: 2/3 = 0.6667 Weighted 2.0/2.6 = 0.7692
- Duke: 1/2 = 0.5000 Weighted 0.6/1.2 = 0.500
- Wisconsin: 0/3 = 0,0000 Weighted 0/3,4 = 0,000
OWP
- UConn: ((Kansas 1.0) (Kansas 1.0) (Duke 1.0) (Wisconsin 0.0))/(4 permainan) = 0.7500
- Kansas: ((UConn 1.0) (UConn 1.0) (Wisconsin 0,0))/(3 game) = 0,6667
- Duke: ((UConn 0.6667) (Wisconsin 0.0))/(2 game) = 0.3333
- Wisconsin: ((UConn 0.6667) (Duke 0.0) (Kansas 0.5))/(3 game) = 0,3889
OOWP
- UConn: ((Kansas 0.6667) (Kansas 0.6667) (Duke 0.3333) (Wisconsin 0.3889))/(4 permainan) = 0.5139
- Kansas: ((UConn 0.7500) (UConn 0.7500) (Wisconsin 0.3889))/(3 permainan) = 0.6296
- Duke: ((UConn 0.7500) (Wisconsin 0.3889))/(2 game) = 0.5694
- Wisconsin: ((UConn 0.7500) (Duke 0.3333) (Kansas 0.6667))/(3 permainan) = 0.5833
These are then combined through formulas
- RPI = (WP * 0.25) (OWP * 0.50) (OOWP * 0.25)
produce the following levels:
- UConn: 0.77066
- Kansas: 0.6830
- Duke: 0.44340
- Wisconsin: 0.3403
The RPI formula also has many shortcomings. Due to the heavy weight of an opponent's winning percentage, beating a team with a bad RPI can really hurt your RPI. In addition, the loss of a good RPI team can help your RPI.
Quadrant
In recent years, one criterion for determining selection to the NCAA Tournament is performance against certain RPI quadrants. Usually, quadrant victory 1 is considered a "good victory", while quadrant loss 4 is considered a "bad loss". Quadrants are defined as follows:
- Quadrant 1: The home game vs. the RPI team is ranked at the top 30; neutral vs. game 1-50; away vs. away matches 1-75.
- Quadrant 2: House vs. 31-75 teams; neutral vs. 51-100; go vs. 76-135.
- Quadrant 3: Home vs. 76-160 teams; neutral vs. 101-200; vs. vs. far away 136-240.
- Quadrant 4: Home vs. team 161-plus; neutral vs. 201-plus; vs. vs. far away 241-plus.
Maps Rating percentage index
Baseball formula
The formula used in the NCAA baseball is the same as that used in basketball except for the adjustment of home and street records. Starting in 2013, the campus baseball RPI formula respects each road triumph as 1.3 instead of 1.0. Each cage win is worth 0.7 instead of 1.0. Instead, each home loss is calculated 1.3 against the team's RPI and each road loss counts 0.7 against the RPI team. The game on the neutral site has a value of 1.0, but the committee is studying how to determine whether a match should be considered a neutral site contest. This adjustment is based on data showing that the home team won about 62 percent of the time in my division baseball. "The change was made because of the difference in the number of home teams playing.Some schools can play 35-40 of 56 matches allowed at home, while other teams, due to factors such as the weather, may only play 20 home games.
This adjustment replaces the current bonus or penalty system that the team received. Bonus points are awarded to defeat top-75 non-conference opponents on the road and penalty points awarded for losing out of 75 non-conference opponents at home. Bonuses and penalties are on a sliding scale, separated into groups of 25, with top bonuses for winning roads against top-25 teams and the worst penalty for losing home to 25 opponents down.
See also
- Braketologi
References
Source of the article : Wikipedia
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