RPI tweaks made official for football, baseball and boys soccer

(Ryan Casey/CHSAANow.com)

AURORA — Three sports tweaked the RPI formula they will use for postseason qualification.

Baseball, football and boys soccer all made slight adjustments after their proposals to do so were passed by the Legislative Council at its meeting on Thursday.

The Ratings Percentage Index (RPI) formula uses the following components in weighing the relative strength of a team: A team's winning percentage (WP), the winning percentage of a team's opponents (OWP), and the winning percentage of the opponents of a team's opponents (OOWP).

The standard RPI formula used is:

RPI = (¼ × WP) + (½ × OWP) + (¼ × OOWP)

But those three sports have changed slightly the percentages they will be using.

Starting immediately with the 2017 spring season, baseball will use:

RPI = (0.35 × WP) + (0.35 × OWP) + (0.30 × OOWP)

Starting in fall 2017, football will use:

RPI = (0.375 × WP) + (0.375 × OWP) + (0.25 × OOWP)

Starting in fall 2017, boys soccer will use: 

RPI = (0.35 × WP) + (0.35 × OWP) + (0.30 × OOWP)

Note that girls soccer will continue to use the standard formula for the current spring 2017 season. It is possible the soccer change could be addressed again at the April Legislative Council meeting. However, if that doesn't happen, both boys and girls will use 35/35/30 after the fall 2017 season.

The following sports have decided to continue using the standard RPI formula:

  • Field hockey
  • Softball
  • Volleyball

A few other team sports do not present their reports until the April meeting, including basketball, hockey and lacrosse. Of those, only lacrosse has met this season, and that sport has not recommended any changes to the RPI.