Penn State 2021 Season News

The RPI does a couple things right. It weighs matches against teams with better win percentages higher than those against weaker teams. 50% of the RPI formula is based on the opponent’s winning percentage, which means that playing teams with better records gives a larger RPI boost.

The other half of the formula revolves around other winning percentages.

The RPI formula is 0.25 (team’s winning percentage) + 0.5 (opponent winning percentage) + 0.25 (opponent’s opponent winning percentage).

The RPI lacks theoretical justification from a statistical standpoint. Other ranking systems which include the margin of victory of games played or other statistics in addition to the win/loss results have been shown to be a better predictor of the outcomes of future games. However, because the margin of victory has been manipulated in the past by teams or individuals in the context of gambling, the RPI can be used to mitigate motivation for such manipulation. 

Some feel that the heavy emphasis upon strength of schedule gives an unfair advantage to teams from major conferences. Teams from "majors" are allowed to pick many of their non-conference opponents (often blatantly weaker teams). Teams from minor conferences, however, may only get one or two such opponents in their schedules. Also, some mid-major conferences regularly compel their member teams to schedule opponents ranked in the top half of the RPI, which could boost the strength of that conference and/or its tougher-scheduling teams. In basketball, the Missouri Valley Conference has successfully done this: It has become one of the top-rated RPI conferences, despite having very few of its teams ranked in the two national Top 25 polls.[4] In 2006, the NCAA began to release its RPI calculations weekly starting in January. Independent sources, such as ESPN or CNN/SI, also publish their own RPI calculations, which are updated more frequently.