Rating percentage index
Commonly known as 'RPI,' the Ratings Percentage Index is a rating system where NCAA basketball teams are ranked. This system has been in use since 1981 to aid in selecting and seeding of the teams appearing in the 65-team playoffs (see also, March Madness). The weights are 25% winning percentage, 50% Strength of Schedule, and 25% opponent Strength of Schedule. The NCAA does not release the RPI to the public, but independent sources, such as ESPN or CNNSI, usually publish their own calculations.