The Rating Percentage Index (RPI) has been used by the NCAA men's basketball committee since 1981 and officially by the women's basketball committee since 1984 as supplemental data to help select at-large teams and seed all teams for the men's and women's NCAA basketball tournaments. The NCAA does not make the RPI available to member institutions in-season because the data are kept confidential within the committees. Collegiate Basketball News duplicates the adjusted RPI that is generated by the NCAA to four decimal places using available formulas without input from the NCAA. The four component factors which make up the RPI are as follows:

Factor I is the team's Division I winning percentage and is 25 percent of the RPI. Games against non-Division I opponents are not included in the normal RPI.  For the men, beginning in 2004-05, home wins are weighted 0.6, neutral wins 1.0, and road wins count 1.4, with similar weights given to losses.

Factor II is the team's opponents' Division I winning percentage, or the team's schedule strength, excluding results against the team in question. It is 50 percent of the RPI.

Factor III is the team's opponents' opponents' Division I winning percentage, or the team's opponents' strength of schedule, excluding results against the team in question. Factor III is 25 percent of the RPI.

Factor IV is the bonus/penalty portion of the RPI and when used in conjunction with Factors I, II, and III is called the Adjusted RPI. It is used only for the women's RPI at this time.  Factor IV first starts with the "normal" RPI as described by Factors I, II and III listed above, and bonus and penalty points are then awarded in two different categories. The first is based on the team's non-conference schedule using the normal RPI ranking of the team's opponents. Bonus and penalty points in the second category are based upon winning games against top 50 teams in the RPI, and on losing to teams ranked lower than 150 in the RPI. Bonus and penalty points in the second category vary based upon the location of the game and are cumulative. A loss to a non-Division I team results in penalty points. The Adjusted RPI was first published in The RPI Report and The Women's RPI Report during the 1998-99 season (it is no longer used for the men beginning in 2004-05).