AURORA — During the Legislative Council meeting on Thursday, the Technology Committee reported on their recommendation surrounding the future of the RPI formula.
The gist of that recommendation: Move away from the standard formula — 25 percent weight on a team's own winning percentage, 50 percent on a team's opponent's, and 25 percent on the opponents of their opponents — to a 30/40/30 model.
The recommendation was delivered to the CHSAA Board of Directors during their meeting on Wednesday. The Board will vote on that recommendation in February.
The Technology Committee has met several times since last August, including an in-person meeting, and several video conferences, in exploring the future of the RPI. Included was a trip to visit with Erik Packard, a statistics professor at Colorado Mesa University who has his own ranking system for high school sports.
The Committee also commissioned a survey of CHSAA member schools asking for their input on the RPI. More than 220 schools responded. That survey showed that:
- Accuracy is the most important factor in a formula.
- They want more weight on their own winning percentage.
- They believe that RPI should be used to set postseason fields, but not to seed them.
Using this feedback as a guide, the Technology Committee then set out to examine all the RPI data CHSAA has ever captured — including from seasons prior to its implementation in 2016.
In order to determine which formula was most accurate, they compared a team's ranking in the final RPI standings of the regular season to their actual performance at the state tournament.
Seven different weights were examined. Because schools had asked for more weight on their own winning percentage, they first looked at a 50/25/25 model. In every case — in every sport — that formula was the least accurate.
In the overwhelming majority of the data, the standard formula (25/50/25) was the most accurate.
A second formula was either the most or the second-most accurate formula in all sports: 30/40/30.
Ultimately, this is the formula the Technology Committee recommended to the Board on Wednesday. The recommendation is that this formula be used in all sports, which will help eliminate the confusion of separate formulas.
Worth noting: It is the most accurate formula for football, too — more accurate than the current formula (37.5/37.5/25) that is being used.
Additionally, the Technology Committee will explore what it would look like if a classification modifier were to be used in all sports.