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RPI Help
The Ratings Percentage Index (RPI) is the formula used by the NCAA to rate men’s and women’s college basketball teams. The formula is described below.
The RPI is calculated by adding three parts.
Part I (25% of the formula): Team winning percentage. For the 2005 season, the NCAA added a bonus/penalty system, where each home win or road loss get multiplied by 0.6 in the winning percentage calculation. A home loss or road win is multiplied by 1.4. Neutral games count as 1.0. More on the effect of these changes can be found here.
Part II (50%): Average opponents’ winning percentage. To calculate this, you must calculate each opponent’s winning percentage individually and average those figures. This is NOT calculated from the opponents’ combined record. Games involving the team for whom we are calculating the RPI are ignored.
Part III (25%): Average opponents’ opponents’ winning percentage: Basically taking all of the opponents’ Part II values and averaging them.
Only games against other teams playing a mostly D1 schedule count when computing the RPI.
Here’s a simple example of how it’s calculated:
Team A has played two games and beat Team B and Team C.
Team B has a 1-1 record. Team B beat a team with a 2-1 record and lost to 2-0 Team A.
Team C has a 1-2 record. Team C beat a team with a 0-2 record, lost to a team with a 2-0 record, and lost to Team A.
So now let’s see how to compute Team A’s RPI.
At 2-0, their winning pct. is 1.000.
Their average opponents’ winning percentage (OWP):
Team B is 1-0 (1.000) without the loss to Team A. Team C is 1-1 (.500) without the loss to Team A. So the OWP is (1.000 + .500)/2 = .750.
Their average opponents’ opponents’ winning percentage (OOWP):
To do this, we need Team B’s and Team C’s OWP. When removing Team B’s results, Team B’s opponents are 2-0 and 1-0 for an average of 1.000. Team C’s opponents are 0-1, 1-0, and 1-0 for an average of .667. The average of these two numbers is .833.
So Team A’s RPI is 1/4 X (1) + 1/2 X (.75) + 1/4 X (.833) = .8333
Here’s how other columns in the RPI grid are computed…
SOS (Strength of Schedule): This is the last two components of the RPI formula:
(2/3) X Opponents Winning Pct. + (1/3) X Opponents Opponents Winning Pct.
Non Conference RPI: This is computed applying the basic RPI formula only to a team’s non-conference games. A common misconception is that a team’s non conference RPI will remain the same after they have played their last non-conference opponent. This is not true because a team’s non-conference opponents’ records and their opponents’ records change as they play their conference games. This can have a substantial effect on the NCRPI. For example, in 2003 Alabama’s NCRPI had a ranking of #23 when they entered conference play. By the end of the regular season it had risen to #3.
L10 (Last 10 Games): A team’s record in their last 10 games against Division I opponents.
RD/NT (Road/Neutral Record): A team’s record away from its home court.
The Ratings Percentage Index (RPI) is the formula used by the NCAA to rate men’s and women’s college basketball teams. The formula is described below.
The RPI is calculated by adding three parts.
Part I (25% of the formula): Team winning percentage. For the 2005 season, the NCAA added a bonus/penalty system, where each home win or road loss get multiplied by 0.6 in the winning percentage calculation. A home loss or road win is multiplied by 1.4. Neutral games count as 1.0. More on the effect of these changes can be found here.
Part II (50%): Average opponents’ winning percentage. To calculate this, you must calculate each opponent’s winning percentage individually and average those figures. This is NOT calculated from the opponents’ combined record. Games involving the team for whom we are calculating the RPI are ignored.
Part III (25%): Average opponents’ opponents’ winning percentage: Basically taking all of the opponents’ Part II values and averaging them.
Only games against other teams playing a mostly D1 schedule count when computing the RPI.
Here’s a simple example of how it’s calculated:
Team A has played two games and beat Team B and Team C.
Team B has a 1-1 record. Team B beat a team with a 2-1 record and lost to 2-0 Team A.
Team C has a 1-2 record. Team C beat a team with a 0-2 record, lost to a team with a 2-0 record, and lost to Team A.
So now let’s see how to compute Team A’s RPI.
At 2-0, their winning pct. is 1.000.
Their average opponents’ winning percentage (OWP):
Team B is 1-0 (1.000) without the loss to Team A. Team C is 1-1 (.500) without the loss to Team A. So the OWP is (1.000 + .500)/2 = .750.
Their average opponents’ opponents’ winning percentage (OOWP):
To do this, we need Team B’s and Team C’s OWP. When removing Team B’s results, Team B’s opponents are 2-0 and 1-0 for an average of 1.000. Team C’s opponents are 0-1, 1-0, and 1-0 for an average of .667. The average of these two numbers is .833.
So Team A’s RPI is 1/4 X (1) + 1/2 X (.75) + 1/4 X (.833) = .8333
Here’s how other columns in the RPI grid are computed…
SOS (Strength of Schedule): This is the last two components of the RPI formula:
(2/3) X Opponents Winning Pct. + (1/3) X Opponents Opponents Winning Pct.
Non Conference RPI: This is computed applying the basic RPI formula only to a team’s non-conference games. A common misconception is that a team’s non conference RPI will remain the same after they have played their last non-conference opponent. This is not true because a team’s non-conference opponents’ records and their opponents’ records change as they play their conference games. This can have a substantial effect on the NCRPI. For example, in 2003 Alabama’s NCRPI had a ranking of #23 when they entered conference play. By the end of the regular season it had risen to #3.
L10 (Last 10 Games): A team’s record in their last 10 games against Division I opponents.
RD/NT (Road/Neutral Record): A team’s record away from its home court.
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