2025 ARTICLE 10: 2025 PRE-SEASON PREDICTIONS AND INFORMATION, PART 4, TEAMS' NCAA RPI RANKS COMPARED TO THEIR RANKS AS STRENGTH OF SCHEDULE CONTRIBUTORS

The NCAA RPI has a major defect, which is the way in which it computes a team's strength of schedule.

As discussed on the RPI: Formula page at the RPI for Division I Women's Soccer website, the NCAA RPI has two main components:  a team's Winning Percentage and its Strength of Schedule.  Within the overall NCAA RPI formula, the effective weights of the two components are approximately 50% Winning Percentaqge and 50% Strength of Schedule.

Within the NCAA RPI formula, in turn, Strength of Schedule consists of two elements: the average of a team's opponents' winning percentages (OWP) and the average of a team's opponents' opponents' winning percentages (OOWP).  And, within Strength of Schedule, the effective weights of these two elements are 80% opponents' winning percentage and 20% opponents' opponents' winning percentage.  Thus for the NCAA RPI's Strength of Schedule component, a team's opponents' winning percentages matter a lot and against whom they achieved those winning percentages matters little.  This is a major defect.

In this and the next two parts of my Pre-Season Predictions and Information, using end-of-season predictions for the 2025 season, I will show how the NCAA RPI's strength of schedule defect plays out for teams (this Part 4), for conferences (Part 5), and for geographic regions (Part 6).

The following table shows, for each team, its predicted end-of-season NCAA RPI rank and its predicted rank as a strength of schedule contributor under the NCAA RPI formula.  In a good rating system, these ranks should be the same or, at least, very close to the same.  As the table shows, however, for the NCAA RPI formula, for many teams, the ranks are not close to the same.

Using some of the top teams in the alphabetical list as examples:

If Team A plays Air Force as an opponent, Team A will have played the NCAA RPI #232 ranked team.  When computing Team A's rating and rank, however, the NCAA RPI formula will give team A credit only for playing the #274 team.

On the other hand, if Team A plays Alabama State, Team A will have played the #340 team.  But when computing Team A's rating and rank, the NCAA RPI formula will give Team A credit for playing the #277 team.

Thus although the NCAA RPI ranks Air Force and Alabama State 108 rank positions apart, when considering each of their strengths for purposes of Team A's strength of schedule computation, the NCAA RPI treats Air Force and Alabama State as roughly equal.

You can scroll down the table and see how this NCAA RPI formula defect plays out for teams you are interested in,  I suggest you look, in particular, at teams in the middle to lower levels of top tier conferences and at teams in the upper levels of middle and bottom tier conferences.  For example:

Look at Alabama:  Its predicted NCAA RPI rank is #37.  But, its predicted rank as a strength of schedule is only #89.

Then look at Bowling Green:  Its predicted NCAA RPI rank is #86 but its predicted rank as a strength of schedule contributor is #26.

These kinds of differences have significant practical implications related to scheduling and the NCAA Tournament.  Teams' NCAA RPI ranks are a key factor in the Women's Soccer Committee's decisions on Tournament seeds and at large selections.  So, if a coach has NCAA Tournament aspirations, from strictly an NCAA RPI perspective, Bowling Green would be a significantly better opponent to play than Alabama.  This would be true for two reasons: (1)  Bowling Green probably is weaker than Alabama, so an easier game in which to get a good result; and (2) Bowling Green, as an opponent, will give the coach's team's NCAA RPI a better strength of schedule contribution than Alabama.

Thus when doing non-conference scheduling, coaches with NCAA Tournament aspirations or with other concerns about where their teams will finish in the NCAA RPI rankings must take this NCAA RPI formula defect into account.  In essence, they are in the position of having to learn how to "trick" the NCAA RPI through smart scheduling -- in the example, choosing Bowling Green rather than Alabama as an opponent.