What Is RPI?
The Rating Percentage Index is a mathematical measurement of a team's strength.
The NCAA tournament selection committee uses it to help determine which 34 teams will receive at-large bids. The formula consists of a team's winning percentage against Division I opponents (25 percent), the opponents' average winning percentage (50 percent) and the opponents' opponents' average winning percentage (25 percent).
Road victories are multiplied by 1.4 in the portion of the formula that deals with a team's winning percentage, while home victories are multiplied by 0.6.
A team with an RPI that is in the top 40 is in fairly good shape to earn an NCAA tournament invitation. A team with an RPI that is 50th or worse is in danger of being excluded.