# How Is RPI Calculated?

By Steve Wozniak

Just about every Selection Sunday when the NCAA Men's Basketball Tournament field is announced, some pundit and insider will discuss how you can't ignore one team's RPI. But what is this strange stat? In a nutshell, the Rating Percentage Index combines a team's own winning percentage with its strength of schedule. The formula is easy, but the actual calculation takes some data mining.

## The Basic Formula

The RPI is calculated by using 25 percent of the team's winning percentage; 50 percent of its opponents' average winning percentage; and 25 percent of its opponents' opponents' average winning percentage. A team with a record of 8-0, opponents' winning percentage of .600 and opponents' opponents' winning percentage of .450 would have an RPI of 0.6625. That would read: (1.000 x 0.25) + (0.600 x 0.50) + (0.450 x 0.25) or 0.2500 + 0.3000 + 0.1125= 0.6625. The most difficult part is tracking down the wins and losses of opponents and opponents' opponents' records for the calculations.