Washington’s Rating Percentage Index (RPI) for Team Sports

Frequently Asked Questions

The RPI will be utilized again during this upcoming season for basketball.  The 2017-18 school year will be a study year for all team sports and all full game scores need to be reported into MaxPreps.  The RPI could expand into other sports as soon as the 2018-19 school year.

RPI-Related News Releases

9/26/2016:  Executive Board Votes to Change Basketball Format, Implement RPI 
11/16/2016:   WIAA Executive Board Approves RPI Committee 
1/6/2017:  Initial RPI Released 
3/29/2017:  Board Action Includes RPI Changes to Include Out-of-State Opponents' Records and Postseason Contests 

What is RPI?
RPI, Rating Percentage Index is a statistical system used to comparatively rank teams.

What is the purpose of the RPI?
The purpose of the RPI is to seed teams onto the state brackets (team sports only) using this statistical system.
What is the formula of the Basketball RPI?
The formula used is as follows: RPI = (40% x WP) + (40% x OWP) + (20% x OOWP)

  • WP (Winning Percentage): Divide the number of wins by the number of total games played for your team.
  • OWP (Opponents Winning Percentage): Average of the winning percentage of a team’s opponents (Note: this is not calculated via the combined record of the opponents, but rather by averaging the winning percentage of the opponents).
  • OOWP (Opponents’ Opponents Winning Percentage: Same process as OWP except the calculation is with the opponents of the team’s opponent. Note: there is an exception for out-of-state opponents – see below.

How will out-of-state opponents be calculated?
Any Washington teams that play out-of-state teams will be expected to input that team’s schedule and scores on a weekly basis throughout the season.
Will postseason games be taken into consideration?
Yes, all games played through the District qualifying tournaments will be included.
What is important to make RPI successful?
Score reporting is essential for an accurate RPI. Scores will be collected via MaxPreps and the RPI will be published exclusively on the WIAA website (basketball only at this time). Other publication sites may not be accurate.
Where should scores be reported?
Scores must be reported via MaxPreps. The official RPI will be based on the scores reported.
Should scores from the jamboree be reported?
No, only scores from full games should be reported.
How will the RPI be published?
Only the Basketball RPI will be published on the WIAA website.
Is the RPI for all classifications?
The RPI will be used for all classifications.

What is the impact of cross-classification games?
The formula does not take into account classifications. A team will not be penalized for playing a team in a lower classification nor rewarded for playing against a team in a higher classification (see how the formula is calculated above).
Does the score differential matter in the RPI?
The RPI is based on a win loss formula. Score differential will have no bearing on the RPI.
What if teams have a different amount of games?
The RPI formula works off the averages of three components: winning percentage, opponents’ winning percentage and opponents’ opponents winning percentage, so an imbalance of one or two games between teams will have virtually no impact on the ranking system.
Is a team’s RPI based on the opponent’s record at the time the game is played or is the RPI based on the final season record of their opponents?
The final RPI calculations used for seeding purposes will be based on the final records of all teams.
How is the strength of schedule (SOS) determined?
SOS is .5*OWP+.25*OOWP
Who will determine if the RPI will be used for other team sports in the future?
The RPI Committee will review the study results in all team sports at the end of the 2017-18 school year, and will make recommendations to the WIAA Executive Board regarding the future implementation of the RPI in other team sports.

Which volleyball scores should be reported?
Only matches that are best-of-3 or best-of-5 should be entered into MaxPreps. Any tournament matches that are shorter in length should not be listed on a schedule and should not be reported.

How are soccer scores reported?
The score of the match should be submitted. One point is added if the team wins in a shootout. A match that ends in a tie will be counted as a .5 win and .5 loss for the team's winning percentage.

Is the MaxPreps RPI formula the one that will be used for football and all other team sports?
The rankings seen on the MaxPreps site use a different formula than the unpublished RPI being tested by the WIAA and should not be confused as being the same. The RPI Committee will review different formulas that might be utilized in Washington.

Updated 8/16/2018

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