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01/28/19- Preliminary Information About Calculating the RPI

February 20, 2019 Athletic Department Blog Updates

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BASICS ABOUT THE RPI

  • RPI will be implemented in all sports as a publicity tool.
  • In Football, the RPI will be incorporated into the tournament rules as a means of seeding Rounds 3, 4 and 5
  • RPI stands for “Ratings Percentage Index”. In short, it is a way to measure a team’s strength relative to other teams, based largely on the strength of their schedules.
  • The RPI formula is used by both the NCAA and NAIA, along with many high school associations and among other organizations, as part of their postseason system.
  • Final details will be released with the first RPI calculations in September, 2019.

What percentages are being used in the formula?

  • Starting in 2018-19, the formula will be as follows for all sports:
    • Each game RPI = GR*((0.35 × WP) + (0.35 × OWP) + (0.30 × OOWP))
    • Total RPI is summative
    • GR=Game Result. 1.0 for a win, .5 for a tie, 0 for a loss
    • WP=Winning Percentage of the Team being reviewed
    • OWP=Opponents Winning Percentage
    • OOWP=Opponents’ Opponents Winning Percentage

Why use RPI instead of another type of rating system?

  • A major advantage to the RPI is the transparency that comes along with its accuracy.
  • The components of the formula are known, and its results can be easily replicated.
  • In addition, there is no incentive for a team to defeat a team by a higher margin, margin doesn’t matter.

What data will be used in the RPI formula?

  • All varsity games played in the regular season shall be counted toward the RPI calculation.

Where will be the RPI standings be published?

  • The official KHSAA RPI standings will be published on khsaa.org.
  • It is worth noting that any RPI data published elsewhere is unofficial and should be viewed with skepticism as it may not be correct.

How are the components of the formula specifically calculated?

  • Winning percentage (WP): Divide the number of wins by the number of total games played.
    • A tie is worth half a win.
    • If a win in an individual contest gives that contest a winning percentage of 1.00, a tie would give that individual contest a winning percentage of .500 for both teams.
    • Opponents’ winning percentage (OWP): Average the winning percentages of a team’s opponents. (Note: This is not calculated via the combined record of the opponents, instead by averaging each winning percentage of the opponents.)
    • All games involving the team whose RPI is being calculated are ignored in this process.
  • Opponents’ opponents winning percentage (OOWP): The same process as described above, except calculated for the opponents of a team’s opponents.
  • Note that there is an exception for out-of-state teams, which is addressed

How will out-of-state opponents be handled?

  • All out-of state opponents will initially be handled in the following manner:
  • Their direct winning percentage (for example, .750) will count toward the formula, but each of their opponents will have a .500 winning percentage assigned.
  • Were this not the case, schools would be chasing tens of thousands of opponents of out-of-state opponents over the course of a season, and there is no way to ensure the accuracy of that data.
  • The .500 figure was selected because it is the average value of opponents’ opponents winning percentages across all sports.

How will international opponents be handled?

  • Due to the difficulty involved with obtaining accurate data on a consistent and timely basis from schools outside the U.S., international opponents will not count toward the RPI calculation.

What happens if two teams are tied in the final RPI standings?

  • The tiebreaker will sequentially be as follows for this unlikely scenario. It is as follows:
    • Head-to-head result between the two teams
    • Winning percentage
    • Opponents’ winning percentage
    • Opponents’ opponents winning percentage
    • Highest-rated win (according to the final RPI standings)
    • Next-highest rated win (exhaust all possibilities)
    • Coin flip – The only reason for the coin flip is as a last result if all other scenarios happen to be tied.

What happens if three teams are tied in the final RPI standings?

  • The tiebreaker will be as follows for this unlikely scenario. It is as follows:
    • Step One
      • Head-to-head result between the three tied teams to determine if one has defeated the other two
      • If one has defeated the other two, that team wins the tiebreaker and the two team tiebreaker shall break the remaining tie
    • Step Two
      • Head-to-head results between the three tied teams to determine if one has lost to the other two
      • If one has been defeated by the other two, that team is eliminated from the tiebreaker and the two team tiebreaker shall break the remaining tie
    • Step Three
      • If Steps one and two do not break the tie, the following steps shall be used in sequence until one of the steps breaks the tie, and then the two team tiebreaker shall break the remaining tie
      • Overall Winning percentage
      • Opponents’ winning percentage
      • Opponents’ opponents winning percentage
      • Highest-rated win (according to the final RPI standings)
      • Next-highest rated win (exhaust all possibilities)
      • Draw – The only reason for the Draw is as a last resort if all other scenarios happen to be tied in which case the draw team would prevail in the tiebreaker and the two team tiebreaker shall break the remaining tie
  • How should teams be scheduling?
    • The main thing to remember with the RPI is it takes an entire schedule into account.
    • Do not fret over scheduling one game.
    • Instead, see the entire schedule as a whole and try to judge if it will be tough or not.
  • Does the score of the contest matter in the RPI formula?
    • Only in that it gives a winner and a loser (or results in a tie).
    • There is no factor for score differential in the RPI formula.
    • A 1-0 win counts the same as 100-1.
  • What happens if a game is cancelled and can’t be rescheduled?
    • Because the RPI system works off of averages, it won’t make a difference in the final formula if a game cannot be rescheduled.
    • It would not penalize, nor benefit, any team involved in that scenario.
  • How do schools that drop programs affect the RPI?
    • If a school drops a program prior to the start their competitive season, no forfeits will be involved.
    • Instead, their opponents now have open dates in the sports where they were scheduled to play the teams who dropped their program, and they are free to try and find another game, if possible.
    • If a school drops a program after their competitive season has started, that team shall forfeit their remaining games to their opponents.
    • In this instance, the competitive season is defined as the first day a team plays in a contest.
  • Where should we be reporting scores?
    • Continue reporting scores to Riherds.com scoreboard.
    • The official RPI feed will be calculated off of results entered into that platform.
  • How often will the RPI standings be published?
    • The RPI standings will not publish for the first time until a season nears the midway point.
    • Once they do, feeds will be updated nightly during the regular season
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