July 21, 2009


Proposal for Changes in Computing RPI - Part 1


Greg Van Zant, the head coach at West Virginia University, recently sent the following recommendation to the NCAA Division I Baseball Committee to change the formula for calculating the Ratings Percentage Index (RPI).





As you know, the Ratings Percentage Index (RPI) is a very important tool that ranks NCAA Division I Baseball teams from 1 to 302.  This RPI ranking aids the NCAA Division I Baseball Committee in a very difficult job of selecting at-large teams for the NCAA Baseball Tournament.  Therefore, it is extremely critical that the RPI formula produces the most accurate ranking possible.


The RPI was first used for baseball in 1984 and was then slightly modified in 1994.  Fifteen years later, it is now time to reevaluate the RPI formula for baseball so that it can be strengthened for our sport.


There are four different facets of the RPI that need to be examined:

  1.   The weighting of the three RPI components or factors.

  2.   The weighting of home wins and road wins.

  3.   The four exempted contests against non-Division I opponents.

  4.   The bonus and penalty system.


My proposal is as follows:

  1.   Change the weighting of the three RPI factors to 50-35-15.

  2.   Count a road win as 1.25, a neutral win as 1.0 and a home win as 0.83333333.

  3.   Penalize teams for playing non-Division I opponents.

  4.   Eliminate the bonus and penalty system.


The following pages will explain my proposed changes to strengthen the RPI.


Accurately ranking 302 Division I college baseball teams from top to bottom is not easy.  It would be easy if each team could play each of the other teams once at home and once away in the same season for a total of 602 regular season games.  Then we could simply use winning percentage for the standings, since each team's schedule would be identical.  Obviously this is not possible.  Ranking the teams from 1 to 302 over a 56 game schedule based on winning percentage does not work because of the differences in each team's strength of schedule.  The Ratings Percentage Index (RPI) is a mathematical formula used to rank the teams that factors in each team's strength of schedule.


Part 2 - The Weighting of Three RPI Factors


Part 3 - The Weighting of Home Wins and Road Wins


Part 4 - Exempt Contests vs. Non-Division I Teams; Bonus & Penalty System


(photo by Jimmy Jones)