2025 ARTICLE 15: RPI REPORT AFTER WEEK 2 GAMES

In this week's RPI Report, I want to point out two sets of data that the Women's Soccer Committee and coaches should be concerned about.  Following that discussion, I'll post the regular weekly team, conference, and region tables.  For those who want to go directly to the weekly tables, here is a link to this week's Excel workbook 2025 RPI Report After Week 2.  (For those seriously interested in the current RPI Report information, I recommend downloading the workbook in an Excel format rather than using the weekly tables as reproduced below.)

Issue of Concern #1: Distribution of In-Region Ties, by Region

This table shows, for each of the four regional playing pools, the percentage of in-region games that are ties.  The percentage is based on actual ties to date and tie likelihoods for games not yet played.  The percentages in the table may be a little higher than they will be at the end of the season, but the placement of the regions in the table is consistent with what the placement has been historically.

Here is the problem the Committee and coaches should be concerned about:

As I have demonstrated elsewhere, the NCAA RPI historically has discriminated against teams from the West region, meaning that in games against teams from other regions, the West region teams on average have performed better than their ratings say they should have performed, i.e., are underrated.  At the other end of the spectrum, the South region teams on average have performed more poorly than their ratings say they should have performed, i.e., are overrated.  This doesn't mean all teams from the regions are under- or overrated, rather that on average teams from the regions are under- or overrated.

This year, the Committee made an NCAA RPI formula change that relates to this:  In the computation of a team's Winning Percentage (half the effective weight of a team's NCAA RPI rating), the Committee reduced the value of a tie from half of a win to one-third of a win.  In other words, it devalued ties.  Since it is reasonable to assume that regions with higher parity will have a higher proportion of ties, the effect of the change is to devalue the ratings of teams from regions with a high level of parity.

Also as I have demonstrated elsewhere, the West region historically has had the highest level of parity, followed by the Middle, then the North, and then the South.  The historic proportion of in-region games that are ties is consistent with this, as are the proportions for this year in the above table.

Thus the effect of the change likely will be to devalue the ratings of teams from the West, followed by the Middle, to the benefit of teams from the North and especially from the South.  This means that with the NCAA RPI already discriminating against teams from the West, the Committee's change has made the discrimination even worse.

The extent to which the Committee has made the change worse is not large, as indicated by the following table:

This table summarizes how the rating systems perform at rating teams from a region in relation to teams from the other regions.  It draws from the following data:

1.  For each region, its teams' actual winning percentages in games against teams from the other regions.

2.  For each region, its teams' expected winning percentages against teams from other regions based on teams' ratings as adjusted for home field advantage. [NOTE: Expected winning percentages are based on the rating differences between opponents as adjusted for home field advantage.  The expected winning percentages are calculated using result probability tables derived from the results of all games played since 2010 and are highly reliable when applied across large numbers of games.]

3.  The difference, for each region, between its actual winning percentage and its expected wining percentage.  Teams from regions with higher actual winning percentages are outperforming their ratings, in other words are underrated (discriminated against), whereas teams from regions with lower winning percentages are overrated.

In the table, the High column shows the actual v expected winning percentage difference for the region whose teams most outperform their ratings when playing teams from other regions -- the West region.  The Low column shows the difference for the region whose teams most underperform their ratings -- the South region.  The Spread column shows the difference between the High and Low, which is a measure of the extent of the rating system's discrimination among regions.  The Over and Under Total column shows the amount, for all four regions, by which the rating system misses a perfect match (no difference) between actual and expected winning percentage, which is another measure of the system's performance.

As you can see from the table's comparison of the two systems, although the difference between the systems' performance is small, the Committee's 2024 change increased the discrimination among regions.

 So, what was the Committee's rationale for the change?  It gave two reasons: (1) Valuing ties as 1/3 of a win matches how conferences compute in-conference standings and how leagues compute standings in the larger soccer world; and (2) The Division 1 men have made the change.

Neither rationale holds water.  (1) For conferences and leagues, for in-conference and in-league standings, there is no issue of whether different playing pools have different levels of parity.  Thus how they count ties, when determining standings, is irrelevant to how to count ties in a national rating system for teams playing games in different geographic regions.  (2) That the men have made the change should be a reason ... Why?  That does not demonstrate in any way that it is a good change for the women.  The Committee should make its own decision based on how the change will affect the NCAA RPI as a rating system for the women's teams, not let the Men's Soccer Committee make the decision for them.

The question the Committee should have considered is whether the change makes the NCAA RPI a better system for rating teams properly in relation to each other when the teams are distributed around the nation and tend to play in different regional playing pools.  They should have asked the NCAA statistics staff about this, and the staff should have advised the Committee that if the geographic playing pools have different levels of parity, then the change will punish teams from the pools with high parity and benefit stronger teams from the pools with low parity.  Did the Committee ask the staff about this and did the staff give them this answer?  I don't know, but I doubt it.

Issue of Concern #2: Proportions of Out-of_Region Games

As I showed above, the NCAA RPI discriminates against some regions and in favor of others.  At one time, I thought this was due exclusively to differences in region strength and there not being a high enough proportion of out-of-region games for the system to work properly on a national basis.  As it turns out, however, both Massey's and my Balanced RPI rating systems show only a small amount of discrimination in relation to region strength, and much less than the NCAA RPI.  In other words, there are enough out-of-region games for those systems to avoid all but a little discrimination in relation to region strength.  So the NCAA RPI's problem has not been driven mainly by there not having been enough out-of-region games (rather, as it has turned out, it is driven by how the NCAA RPI computes Strength of Schedule).

On the other hand, it is indisputable that there have to be "enough" out-of-region games for any rating system to work on a national basis.  As the following tables show, no doubt due to the changing college sports economic landscape, this year there is a substantial reduction in the proportion of out-of-region games from what the proportion has been in the past (based on teams' published 2025 schedules, adjusted to take canceled games to date into account):

This represents a 28.0% across the board reduction in the proportion out-of-region games.  For the Middle region, the reduction is 18.0%, for the North 28.5%, for the South 30.2%, and for the West 31.7%.  Given these reductions, a major question is whether they will significantly impair the ability of the NCAA RPI -- or any other rating system -- to properly rate teams on a national basis.  This is a question the Committee and coaches should be thinking about.

Weekly Team, Conference, and Region Tables

The following tables are based on the actual results of games played through Sunday, August 24, and predicted result likelihoods for games not yet played.

TEAMS

CONFERENCES

REGIONS

2025 ARTICLE 14: RPI REPORT AFTER WEEK 1 GAMES

In 2025 Article 7 and 2025 Article 8, I described how I assign pre-season NCAA RPI ratings and ranks to teams and then, assuming those ratings and ranks represent true team strength, apply them to teams' schedules to generate predicted end-of-season NCAA RPI ratings and ranks.  Once I have done that, at the end of each week of the season I replace that week's predicted results with games' actual results.  Then, using those actual results combined with predicted results for the balance of the season, I generate new predicted end-of-season NCAA RPI ratings and ranks.  After completing week 5 of the season, I will switch from using assigned pre-season NCAA RPI ratings and ranks as the basis for predicting future results to using the then actual NCAA RPI ratings and ranks as the basis.

Using this process, the predicted end-of-season NCAA RPI ratings and ranks are very speculative at the beginning of the season.  However, as each week passes, they become progressively closer to what the actual end-of-season ratings and ranks will be.  By the last few weeks of the season, they become helpful when trying to figure out what results teams need in their remaining games in order to get particular NCAA Tournament seeds or at large selections.

Today's report shows where things are with Week 1's actual results incorporated into the end-of-season predictions.  The report has a page for teams, for conferences, and for geographic playing pool regions.  You can download the report as an Excel workbook with this link: 2025 Week 1 RPI Report.  The same information also is set out in tables below, but I recommend downloading the workbook as it likely will be easier to use.  (If using the tables below, scroll to the right to see additional columns.)

This year, an emphasis in these reports is on showing why the NCAA RPI, because of how it measures the opponents' strengths of schedule that it incorporates into its formula, discriminates against or in favor of particular teams, conferences, and regions.

TEAMS

This page shows, for each team:

Team name

Geographic playing pool region

Conference

If the team is predicted to be its conference's NCAA Tournament automatic qualifier (AQ)

If the team is predicted to be disqualified from an NCAA Tournament at large selection due to having more losses than wins (1)

Team's 

NCAA RPI rank (based on past history, a key factor in selecting teams that will be in the NCAA Tournament #1 through #4 seed pods)

rank as a strength of schedule contributor to opponents under the NCAA RPI formula

Opponents'

average NCAA RPI rank 

average rank as strength of schedule contributors under the NCAA RPI formula

Conference opponents' 

average NCAA RPI rank 

average rank as strength of schedule contributors under the NCAA RPI formula

[NOTE: Teams have relatively little control over this part of their schedules.] 

Non-Conference opponents' 

average NCAA RPI rank

average rank as strength of schedule contributorsl under the NCAA RPI formula

[NOTE: Teams control this part of their schedules, to some extent.  Geographic factors such as travel expenses, available opponents, and other factors can be limiting considerations.]

NCAA RPI Top 50 Results Score

NCAA RPI Top 50 Results Rank (based on past history, a key factor in NCAA Tournament at large selections and in selecting teams that will be in the #5 through #8 seed pods)

Similar rank and strength of schedule contributor rank numbers under the Balanced RPI

KPI rank if available

Massey rank

 

CONFERENCES

This page shows, for each conference:

Conference name

Conference's NCAA RPI rank

Teams' 

average NCAA RPI rank 

average rank as strength of schedule contributors under the NCAA RPI formula 

 Opponents' 

average NCAA RPI rank 

average rank as strength of schedule contributors under the NCAA RPI formula

Conference opponents' 

average NCAA RPI rank 

average rank as strength of schedule contributors under the NCAA RPI formula

Non-Conference opponents' 

average NCAA RPI rank 

average rank as strength of schedule contributorsl under the NCAA RPI formula

Conference's Non-Conference RPI rank 

Similar rank and strength of schedule contributor rank numbers under the Balanced RPI

KPI rank if available

Massey rank

 

REGIONS

This page shows, for each region:

Region name

Number of teams in region 

Region's NCAA RPI rank

Teams' 

average NCAA RPI rank 

average rank as strength of schedule contributors under the NCAA RPI formula 

Opponents' 

average NCAA RPI rank 

average rank as strength of schedule contributors under the NCAA RPI formula

Region opponents' 

average NCAA RPI rank 

average rank as strength of schedule contributors under the NCAA RPI formula

(NOTE: Due to budget limitations, teams may be compelled to play all or most of their non-conference games against opponents from their own geographic regions.] 

Non-Region opponents' 

average NCAA RPI rank 

average rank as strength of schedule contributorsl under the NCAA RPI formula

Similar rank and strength of schedule contributor rank numbers under the Balanced RPI

KPI rank if available

Massey rank

Regions' proportions of games played against teams from each region (NOTE: This years, the numbers of out-of-region games are down about 30% from past patterns.  This may result in a significant degradation of the NCAA RPI's already impaired ability to properly rate teams from a region in relation to teams from other regions.)

Proportion of in-region games that are ties (as a measure of in-region parity) (NOTE: The NCAA RPI, because of how it measures Strength of Schedule, on average discriminates against teams from regions with higher region parity.)

 

2025 ARTICLE 13: 2025 PRE-SEASON PREDICTIONS AND INFORMATION, PART 6, GEOGRAPHIC REGIONS IN RELATION TO NCAA RPI RANKS AND STRENGTH OF SCHEDULE RANKS

This article, for the geographic regions within which the teams from each state play most of their games, provides information similar to that provided for conferences in 2025 Article 12.  A map showing the four regions is at the RPI for Division I Women's Soccer RPI: Regional Issues page.

As you can see, when averaged across a region, the differences between average NCAA RPI ranks and average Strength of Schedule contributor ranks under the NCAA RPI formula are relatively small.  This makes sense, since each region has an array of strong and weak teams and conferences.  As a generalization, however, looking at the numbers for the regions' teams opponents, overall and on average teams from the West region are discriminated against due to the way the NCAA formula computes Strength of Schedule, the Middle region experiences no impact, and the North and South regions are benefitted by discrimination.

To be clear, there are teams and conferences from all of the regions that the NCAA RPI formula discriminates against and in favor of.  The numbers above simply show the net effect of the discrimination for each region.

A particular concern this year is a significant reduction in out-of-region competition, most likeky due to less funding being available for travel.  The following table shows the extent of the reduction looking at the nation as a whole:

As you can see, the number of out-of-region games will be reduced by 28.1% from what the number historically has been.

A break down of the numbers from the preceding table by region shows reductions in the number of out-of-region games as follows:

Middle  18.3%

North  28.5%

South  30.0%

West  31.7%

These reductions should be a concern for the Women's Soccer Committee.  The NCAA RPI already has a problem ranking teams dispersed among the conferences and across the regions within a single national system.  The reductions in out-of-region play are likely to make the problem worse. 

 

2025 ARTICLE 12: 2025 PRE-SEASON PREDICTIONS AND INFORMATION, PART 5, CONFERENCES IN RELATION TO NCAA RPI RANKS AND STRENGTH OF SCHEDULE RANKS

 In 2025 Pre-Season Predictions and Information, Parts 4 and 4B, for the individual teams I showed the relationship between predicted NCAA RPI ranks and Strength of Schedule Contribution ranks under the NCAA RPI formula, both for the individual teams and for their opponents.  In this article, I will show the same information, but for each conference.  This gives a good picture of how the NCAA RPI discriminates among conferences because of the defective way it calculates Strength of Schedule.

This table has the conferences in NCAA RPI rank order, based on the average rating of their teams.  See below the table for comments.

In the table, the first two green-highlighted columns on the left show, for each conference, the difference between its teams' average NCAA RPI rank and its teams' average Strength of Schedule contributor rank under the NCAA RPI formula.  As you read down the table from the strongest conferences at the top to the weakest at the bottom, you can see the clear pattern: For stronger conferences, the conference teams' Strength of Schedule contributor ranks are poorer than the teams' actual ranks say they should be; and for weaker conferences they are better than they should be.

The next two salmon-highlighted columns look at how this plays out for the conference teams' schedules.  The first of those columns shows the conferences' teams' opponents' average ranks and the second column shows those opponents' average ranks as Strength of Schedule contributors.  The pattern here is the same:  Stronger conferences' opponents' Strength of Schedule Contributor ranks are poorer than the opponents' actual ranks say they should be; and the opposite is true for the weaker conferences.

The next four columns break the numbers for the conference teams' schedules down into conference opponents (green-highlighted) and non-conference opponents (salmon-highlighted).  Given that in conference play, the conferences' teams are playing each other, it is no surprise that the contrasts between the conference opponents' NCAA RPI ranks and their ranks as Strength of Schedule contributors follow the same basic pattern.  For the non-conference opponents, where the individual teams have more control over their schedules, the pattern is similar but less extreme and with a little more variability.

It is important here to point out that coaches in top tier and most coaches in middle tier conferences are aware of these patterns and often take them into consideration in their non-conference scheduling.  They also are aware, however, that in the NCAA Tournament seeding and at large selection processes, good results against highly ranked opponents matter, including against highly ranked non-conference opponents.  Further, coaches of teams with NCAA Tournament aspirations often want to play at least some strong non-conference opponents.  This means that they sometimes decide to schedule opponents whose Strength of Schedule contributions are likely to be poorer than their RPI ranks say they should be, essentially deciding to take a potential RPI "hit" in exchange for the potential of a good result against a highly ranked opponent.

NOTE:  Being aware of the scheduling dilemma I just described, I designed my Balanced RPI, which is a modification of the NCAA RPI, with the specific objective of eliminating the difference between teams' ranks and their ranks as Strength of Schedule contributors.  Thus under the Balanced RPI, if a team has a rank of X, that also is either exactly or very close to exactly the team's rank as a Strength of Schedule contributor.  In other words, if the NCAA were to use the Balanced RPI, coaches no longer would have this scheduling dilemma.   (As an additional benefit, the RPI no longer would discriminate among conferences in relation to conference strength.)