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The RPI (Rating Percentage Index) is the formula that is used by the NCAA
Tournament selection committee to determine at-large invitations to the NCAA
Tournament and to seed the selected teams. Recent changes to the RPI formula
will significantly impact college basketball for years to come. To fully
understand the changes to the RPI formula, first one must have a basic
understanding of the RPI and how the formula has been since the mid 1990s. |
The formula
for determining a team's RPI is simple:
- 25% = the team's won/loss percentage.
- 50% = the teams opponents won/loss
percentage, minus games against the team being rated.
- 25% = the teams
opponents, opponents won/loss percentage.
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Only games against division 1 opponents count toward a team’s
RPI. If a team plays another team multiple times, it is scored as if the
team played two different opponents. Where the game was played and how
competitive the losing team was in the game is not considered. All that
matters are wins and losses. |
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The changes to the formula involve a weighting for home and away games. Home
victories will be worth 60% of what they were in the old formula, while home
losses will cost 140% of what they did in the old formula. Road victories
will be worth 140% more than they were in the old formula, while road losses
will only cost 60% of what they did in the old formula. Neutral court wins
and losses will continue to be worth 100% of what they were in the old
formula. |
Let's take Ball State's schedule to this point and apply the
new formula to just the win/loss portion of the Cardinal's rating:
- Ball State's loss to
Kentucky in Cincinnati cost 100% of a loss. Adjusted record: 0 wins, 1
loss.
- Ball State's victory
at Detroit was worth 1.4 victories. Adjusted record: 1.4 wins 1 loss.
- Ball State's home
victory over Wright State was only worth 60% of a victory. Adjusted
record: 2 wins, 1 loss.
- Ball State's road loss
at Miami was only worth 60% of a loss. Adjusted record: 2 wins, 1.6
losses.
- Ball State's home
victory over IUPUI was only worth 60% of a victory. Adjusted record: 2.6
wins, 1.6 losses.
- Ball State's home
victory over Indiana State was only worth 60% of a victory. Adjusted
record: 3.2 wins, 1.6 losses.
- Ball State's road loss
at Butler only cost 60% of a loss. Adjusted record: 3.2 wins, 2.2 losses.
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By the old formula, Ball
State's won/loss percentage is .571 with 25% or .143 applied to the
Cardinal's RPI. The new formula adjusts Ball State's won/loss percentage to
.593 with 25% or .148 applied to the Cardinal's RPI. Similar adjustments are also made to the
strength-of-schedule part of Ball State's RPI which comprises the remaining
75% of the rating and at this point when all the numbers are added, Ball
State comes out ahead. Under the old formula, Ball States RPI would have
been rated #118 in the country. With the new formula, Ball State's RPI is
rated #105 in the country. A modest gain, but it's great when compared to
what has happened to Indiana's RPI. Both of IU's victories have been at
home, so they count 60% of each of those victories. The Hoosiers suffered
three home court losses, each of which cost 140% of what it would have cost
under the old system. Under the old system, Indiana's RPI would have been
rated #138 in the country. Under the new system, Indiana's RPI plummets to
#217 in the country, a huge difference. These RPI numbers are up to date as
of December 25 and come from Jerry Palm and CollegeRPI.com. |
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What does this mean? It is 140% more important to protect the
home court than in past years. The reward for winning on the road is also
much sweeter. This added benefit might be enough to entice big-name teams to
play lower profile teams on the road or on a neutral court more often. |
