RPI in volleyball stands for Rating Percentage Index. It is a formula used by the NCAA to rank sports teams based on a team's wins and losses and its strength of schedule
. The RPI formula is 0.25 (team's winning percentage) + 0.5 (opponent winning percentage) + 0.25 (opponent's opponent winning percentage)
. It is used to aid in the selecting and seeding of teams appearing in post- season tournaments