IHSAA tweaks RPI formula for football postseason

Last year was the first year of a new system that determined who made the Iowa High School Athletic Association playoffs for football.

The IHSAA began using a Ratings Percentage Index in 2018 to determine its at-large playoff qualifiers. District champions across all six classifications receive automatic qualification into the playoffs.

The IHSAA's RPI Formula takes into account a team's winning percentage, its opponents' winning percentage and the opponents' opponents' winning percentage.

Teams will receive RPI numbers ranging between .0000 and 1.000 (higher is better) through the three criteria weighted at different percentages.

A team's winning percentage accounts for 37.5 percent of its RPI. A team's opponents' composite winning percentage will also account for 37.5 percent of its RPI. the combination is 75 percent of the total. The remaining 25 percent is a team's opponents' opponents' composite winning percentage.

So, for the math whiz out there, RPI = (.375 x WP) + (.375 x OWP) + (.250 x OOWP).

Three-way district ties for the title caused some consternation last year. New in 2019, only one champion will be named out of each district. Two-way ties are broken through head-to-head competition, but with any true three-way ties for district championships, the automatic qualifying spot as district champion will go to the team with the highest RPI. The other two teams will reenter the at-large field and may qualify for the playoffs through RPI or they may not qualify because of their RPI.

Two updates were approved in 2019 to allow head-to-head competition to supersede RPI in select situations following Week 9 competition. If two teams are side-by-side for the final spot in the RPI rankings and have played head-to-head in the regular season, the winner of the regular season contest will receive the at-large spot. If two teams are side-by-side in the final RPI rankings and played in the regular season, the winner of the head-to-head contest will receive the higher playoff seeding.

Locally, both WACO and Winfield-Mt. Union have games with out-of-state opponenets. The IHSAA will calculate the winning percentage of an out-of-state opponent into a team's RPI. However, that opponents' opponents will have a uniform .500 winning percentage assigned.

The IHSAA assigns districts and district schedules every two years and recommends member schools make non-district schedule requests that suit the goals of their football programs. The RPI takes a team's entire schedule into account. Teams often play teams for geographical reasons or rivalry reason in non-district play. Often the result of that is a game against a team in a different class. Teams are neither penalized nor rewarded for playing up or down in classification for their non-district games. A win over a Class A team is calculated the same in RPI as a win over a Class 4A team.

In the past, the point spread in a win was considered. The current RPI system does not factor in margin of victory or whether a victory takes place at home or on the road. Wins and losses determine playoff qualification, either via district championship or RPI ranking for an at-large spot.

Because RPI uses averages, if a game is cancelled and cannot be rescheduled, it will not negatively affect either team in the formula.

However, if a team drops its football program once the competitive season has begun, that team will forfeit its remaining games to their opponents. If a team drops its program prior to the start of the season and leaves open dates, no forfeits will be assigned.

This happened when Tri-County was unable to field a team this season after going 0-8 last year. Tri-County was on WACO's, New London's and Winfield-Mt. Union's schedule last year and this year. Two of the three schools picked up an additional game out of state. WACO will only play eight games this year.

Updated RPI standings will be published at iahsaa.org/football on Mondays after Week 6 of the football season.