RPI: Home/Away/Neutral Issues

Updated June 2025

With one exception, the NCAA computes the NCAA RPI for Division I women’s soccer without regard to game locations.  The exception is the bonus and penalty adjustments the NCAA makes to the unadjusted NCAA RPI and NCRPI  in order to produce the adjusted NCAA RPI and NCRPI.  As discussed on the "RPI: Formula" page, the effects of the adjustments are minimal.

Should the NCAA RPI make a distinction between home, away, and neutral site games (apart from in the bonus and penalty amounts)?  Some critics have said, "Yes."  They argue that teams from strong conferences have leverage that enables them to play more non-conference games at home than away and that this unfairly skews the NCAA RPI in their favor.  To address these kinds of concerns in men's and women's basketball, towards the end of the time during which they used the RPI, there was a change to the RPI formula:  In computing a team's winning percentage, a home win counted as only 0.6 wins and an away win counted as as 1.4 wins; an away loss counted as 0.6 losses and a home loss counted as 1.4 losses; and neutral wins and losses counted as 1 win or loss.  Basketball, however, no longer uses the RPI.

HOME/AWAY IMBALANCES

The first question is whether there really are home/away imbalances in favor of teams from strong conferences.  

To answer this question, I looked at conferences' non-conference game locations from 2013 to the present.  I am using 2013 as the beginning of the period because 2013 was the year of completion of a major conference membership realignment.   The numbers show that, indeed, conferences have favorable and unfavorable home/away imbalances.  And, there is a pattern to the imbalances:  On average, conferences with higher average NCAA RPIs have favorable home game imbalances and conferences with lower average NCAA RPIs have unfavorable home game imbalances. 

The following chart shows the relationship between conferences’ average NCAA RPIs and conferences’ non-conference home game imbalances.  The data points are in order from the conference with the best average NCAA RPI on the left to the conference with the poorest average NCAA RPI on the right:

This chart is clear:  On average, stronger conferences' teams play a higher percent of non-conference games at home than weaker conferences' teams.

HOME FIELD ADVANTAGE

Given that there are home/away imbalances, the next question is: Is there really a home field advantage and, if so, how much?

The answer is set out in detail on the RPI: Measuring the Correlation Between Teams' Ratings and Their Performance page.  There, under the heading Determining the Value of Home Field Advantage and analyzing the value of home field for the 2024 version of the NCAA RPI, I show how I use the Correlator to determine (1) whether there is a home field advantage and (2) if so, the value of home field advantage.

The conclusion, as set out on the Measuring the Correlation ... page, is "yes" there is a home field advantage.  For the 2024 version of the NCAA RPI, home teams perform as though their RPI rating is 0.0085 better than their actual rating and away teams perform as though their RPI rating is 0.0085 poorer.  Thus if you calculate the rating difference between two opponents, to get the effective rating difference for a game, you must include a rating difference adjustment of 0.0085 plus 0.0085, combining to an adjustment of 0.0170, to get the effective rating difference between the opponents.  Or, put differently, home field advantage is worth 0.0170 on the NCAA RPI scale.

SHOULD THE NCAA RPI FORMULA TAKE HOME FIELD ADVANTAGE INTO CONSIDERATION?

As shown on the RPI: Measuring the Correlation Between Teams' Ratings and Their Performance page, under the heading Conferences, even after taking the value of home field into consideration, the NCAA RPI discriminates against teams from stronger conferences and in favor of teams from weaker conferences.  Thus if the NCAA were to change the NCAA RPI formula to reduce the ratings of teams with favorable home field imbalances and increase the ratings of teams with unfavorable imbalances, it would cause the RPI to discriminate even more against teams from stronger conferences and in favor of teams from weaker conferences.  Because of this, the NCAA should not change the RPI to take home field imbalances into consideration.