Are you a newbie looking to understand basketball lingo?  Are you curious to find out what RPI ranking is and how it works in basketball rankings?  If your answer to either of these questions is yes, you have come to the right place.  

Understanding basketball statistics doesn’t always come easy, and we are here to help you.  Through this article, you will not only read about what RPI is, but you will also gain information on how it is calculated.  We will also help you to understand if RPI is a good or a bad thing. 

All you have to do to find the information you are seeking is to keep reading.  This information could be the difference between you understanding your own statistics and pulling ahead in the game of basketball.

What Does RPI Stand for in Basketball?

It’s that time again, and college basketball season is approaching.  It’s time to get in gear for the season.  If you are familiar with basketball, you would know that RPI stands for rating percentage index but is known in short as RPI.  However, if you are new to college basketball, this may be new information for you.  This rating system is used in various sports like hockey, soccer, baseball, and even basketball to rank sports teams within the NCAA. 

Contrary to popular belief, there are several other ranking systems. However, the Rating Percentage Index is one of the most popular. 

How is RPI Calculated in College Basketball?

The NCAA uses a basic formula for calculating a team’s RPI.  However, it becomes increasingly complicated when you factor in the adjustments needed for specific or unique games.  One example of this is that the NCAA has different weights for their victories.  This can be for home games or on-the-road wins.

The RPI is weighted, and the following weights can break down the information below:

• WP: Winning Percentage 25%
• OWP: Opponent’s Winning Percentage 50%
• OOWP: Opponent’s Opponent’s Winning Percentage 25%

RPI = (WP * 0.25) + (OWP * 0.50) + (OOWP * 0.25)

Several people criticize the RPI and feel that it is not a reasonable calculation.  However, this calculation is used for determining a number of things, including seeding and even tournament selection.  

Several other considerations must be taken into account.  These items include additional weighting measures:

• For OOWP and OWP, calculations remain unique because they do not use a reference team when taking into account the win/loss record.  
• Additional weight is also calculated within the WP-based on if the game is an away or a home game.  For away games, regardless of if they are wins or losses, 1.4 is used.  For home games, a weight of 0.6 is used regardless of is they are wins or losses. 

How Do NCAA Basketball Rankings Work?

Now that you know what RPI stands for, it’s crucial to understand how it plays into the NCAA’s rankings. Originally the RPI was used as the NCAA’s ranking tool of choice; this had been in place since 1981.  However, recently that was replaced by the NET rating system.  The NET is a system or tool which allows the NCAA to select teams for the NCAA tournament.  

The NET ranking uses five significant factors.  These factors include the following:

• Net efficiency – the net efficiency is calculated by a given team’s offensive efficiency subtracted from their defensive efficiency.  However, before computing a team’s overall net efficiency, each individual’s efficiency must be calculated. To calculate a team’s defensive and offensive efficiency, the following calculation must be performed.   

– Defensive efficiency: Opposing team’s field goal attempts – Opposing team’s offensive rebounds + opposing team’s turnovers + (.475 x opposing team’s free throw attempts) = Opposing team’s total number of possessions.  The opposing team’s total points are then divided by this value. This number is then referred to as defensive efficiency.

– Offensive Efficiency: A team’s attempted field goals – a team’s offensive rebounds + a team’s turnovers + (.475 x free-throw attempts) = a team’s total number of possessions. The total points a team scored is then divided by the number of possessions from the formula above.  

• Score margin – the score margin is essentially the difference in a team’s points from the opposing team.  This difference, however, is capped to keep gameplay fair.  If a team is over by a margin of 10, the team will only be allowed at most 10 for this section.

• Winning Percentage – The winning percentage is found by taking all of a team’s wins and dividing them by the number of games they have played.
• Adjusted win percentage – This is a weighted percentage and is therefore calculated slightly differently.  There is a different amount added or subtracted based on whether you win or lose as well as where it happens.   For wins, teams have three factors: road wins, neutral wins, and home wins.  For losses, teams have the same options: road, home, and neutral. For a road win, a team will receive a plus 1.4; however, for a road loss, a team will receive a negative .6.  For home wins, a team gets +.6; however, for home losses, a negative 1.4 is obtained. Last but not least, neutral games are awarded a plus one for wins and a negative one for losses. 
• Team value index – this portion of the NET is all about results.  Three different factors go into this item.  These factors are location, winner, and the team’s opponent. This factor allows teams to get accolades for beating teams that are good. 

All of these factors are calculated using a game’s ending results.  When determining ranking, there is a ranking committee for the NCAA.  This committee is responsible for determining the teams which will receive the “at-large” bid for conferences. This is roughly 36 teams.

This committee includes ten schools, as well as a number of different conference administrators.  These individuals use the NET ranking system as well as a number of other scoring systems to select their teams.  The NET is just one factor in this.  Before the change, the rating percentage index would be included.

The selection committee will also use something called team sheets. These sheets provide committee members with an abundance of information about a team’s performance. This sheet provides individuals with a breakdown of all the essential statistical information the committee will need to make their decisions.  This information includes the following:

• NET score information
  • The sheet is broken into quadrants, all based on a team’s NET score.  The sheet sort’s a team’s performance by results. 
• Team standings
• BPI – The BPI uses point averages.  It is a representation of how many points from the average a team is.  This factor is meant to predict how a team will perform for the rest of a given season.  It takes into account several different things like paces, rest days, pre-season expectations, and even the location of a game.  
• KenPom – This is a rating system by Ken Pomeroy.  It includes metrics for efficiency, pace, and even tempo. 
• Sagarin – This is a basketball rating system by Jeff Sagarin, a sports statistician.  He developed this rating method, and it has been utilized and publicized since the early eighties in USA Today.  It has also been used in football. 

These are all factors used to select the 36 teams to receive at large bids.  The other 32 teams are automatically qualified for March Madness by their conference wins. 

Is a High RPI Good or Bad?

The RPI is a system that is often criticized.  Many felt that its calculations were not fair and unjustly penalized the teams.  Since the winning percentages are heavily weighted, high and low RPIs may mean different things in different conferences. In the context of the RPI ranking system, it is less difficult for a team from a major conference to have a high RPI.  For example, in a high-performing conference, a low RPI indicates that this team may be greatly struggling compared to the other teams.  However, depending on the opposing teams in a less known conference, a high RPI may indicate that this team should be watched. 

Generally, a low RPI indicates that a team may be struggling.  However, the RPI must also be compared to a team’s season record.  This will help you determine if a team performs highly in conferences and low during the regular season. 

RPI calculations are often released annually; however, places like CNN and ESPN release their calculations more often.  

Wrapping Things Up: What is RPI in Basketball?

The RPI can be a complicated system to wrap your head around.  Throughout the years, it has received many criticisms for being unfair to different teams.  RPI or Rating Percentage Index has been used for a reasonably long time and only recently was replaced by the NET ranking system. 

The NET ranking system, as well as a number of other ranking systems, are used together to choose teams for March Madness.  All of these rankings are married together on the selection committee’s team sheets.  

Though the RPI is not used for selections, it is still released each year to show how a team performs.

Did you enjoy this post? Then you’ll love the other commonly asked questions about basketball.

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