As Selection Sunday quickly approaches, fans of "bubble teams" everywhere will scrutinize every detail of their team's season trying to determine if they will make it into the 2011 NCAA Basketball Tournament.
One tool used heavily by the NCAA to distinguish between teams under consideration is the Ratings Percentage Index (RPI). The RPI is a mathematical formula that accounts for a team's winning percentage, that team's opponent's winning percentage and the opponent's opponent's winning percentage.
The RPI can be a coach's best friend or worst nightmare. The following will show some careful planning during the scheduling process can go a long way in ensuring a strong RPI at the end of the season.
The first component of the RPI is your team's winning percentage. Wins and losses are weighted by if they occur at home, away or at a neutral site as follows:
- Home Win = 0.6 Win
- Home Loss = 1.4 Loss
- Away Win = 1.4 Win
- Away Loss = 0.6 Loss
- Neutral Win = 1 Win
- Neutral Loss = 1 Loss
Use an example that a team had one home win (0.6 wins), one home loss (1.4 loss), one away win (1.4 win), one away loss (0.6 loss), one neutral win (1 win), and one neutral loss.
The numerator, or top of the equation would be the sum of the weighted wins or:
- 0.6 + 1.4 + 1 = 3
The denominator, or bottom of the equation, would be the sum of the weighted wins and losses or:
- 0.6 + 1.4 + 1.4 + 0.6 + 1 + 1 = 6
The team's weighted winning percentage would then be:
- 3 / 6 = 0.5.
The second component of the RPI is your opponents' average winning percentage.
These values are NOT weighted by location of the game. So for each opponent, simply divide their number of wins excluding games against your team by their total number of games excluding the games against your team. Repeat this for each opponent. To calculate the average opponent winning percentage, add all opponents' winning percentages and divide by the number of opponents.
Keep the assumption that the team in our example has played six teams. Each of these six has played five teams besides your team and all have won three games excluding your team. So for each team, their winning percentage is:
- 3 wins / 5 games = 0.6
The average opponent's winning percentage would then be:
- (0.6 + 0.6 + 0.6 + 0.6 + 0.6) / 5 = 0.6
The third step is to calculate your opponents' opponents' average winning percentage.
To do this, repeat the steps on the previous slide for each of your opponents' opponents and then average those values. For this example, assume that the opponents' opponents' average winning percentage is also 0.6.
The fourth step is to actually calculate the RPI. The RPI weighs the values we calculated in the previous slides as follows:
- Your team's weighted winning % = 25%
- Opponents' average winning % = 50%
- Opponents' opponents' average winning % = 25%
Plugging in the numbers from the other slides, the RPI for the team in this example would be:
- RPI = (0.25 x 0.5) + (0.5 x 0.6) + (0.25 x 0.6) = 0.575
So what does all this mean?
It means scheduling is crucial, because 75 percent of the RPI is dependent upon your opponents' success or failure. If you are a team looking strictly to bolster your RPI, ideal team schedules are those that annually compete for mid to low major conference championships.
Some reliable RPI boosters include Austin Peay State University, Murray State University, Belmont University and Utah State University. These types of schools help all three aspects of the RPI formula.
First, these are usually winnable games which helps with your team's winning percentage.
Second, these teams traditionally average at least 20 wins per season, which will bolster the all-important opponents' winning percentage.
Lastly, these teams also play a lot of buy games, where they are paid by powerhouse programs to go on the road and play. As a result, a large number of their opponents will have high winning percentages.
So if your team misses the 2011 NCAA Tournament because of the RPI, they more than likely have no one to blame but themselves. Scheduling is key. Play winnable road games in the pre-conference season and schedule some reliable RPI boosting teams.
Do these two things and the RPI will likely workout in your favor.