After a four-year study of the Rating Percentage Index, the NCAA Division I Men's Basketball Committee has revised one of the tools it uses to evaluate teams as part of the selection process each year.
The committee, which met in December in Indianapolis, said the adjustment involves giving more weight to playing -- and winning -- games on the road. The new version of the RPI will be used as a tool for the 2005 championship.
"The committee adopted a formula that more accurately reflects the historical data regarding a team's performance at home," said Bob Bowlsby, director of athletics at the University of Iowa and chair of the committee.
Over the past 20 years, home teams have won about two-thirds of all games. The committee initiated the current study of the RPI in summer 2000 and has committed to continue evaluating it.
Bowlsby said information on teams and games is now readily available, and the committee is able to get a complete picture of the teams under consideration based upon many factors without relying extensively on a computerized index.
"The committee continues to view the RPI as one of many pieces of available information used in the process," Bowlsby said. "The committee reaffirmed that teams should continue to be selected and seeded based upon a composite of the committee members' subjective evaluations, rather than on computer models, because no computer can accurately evaluate factors such as games missed by key players, travel difficulties, a team's performance in the last 10 games, etc. Nonetheless, we want the RPI to be the best tool possible. We believe this adjustment accomplishes that."
The mathematical components of the RPI will continue to be 25 percent winning percentage, 50 percent opponents' winning percentage and 25 percent opponents' opponents' winning percentage.
The new formula will weigh each road victory at 1.4, each road loss at .6, each home victory at .6 and each home loss at 1.4 in the win or loss column in the RPI. Neutral-site games will be valued at 1.0 in the win or loss column.
Previously, all games carried the same weight. A fourth factor, which added bonuses or penalties for road performance and schedule strength, has been replaced by the new weightings.
When the RPI was created in 1981, the percentages were 20-40-20; the current 25-50-25 formula was adopted in 1994.
Also, the Division I Men's Basketball Committee reviewed a preliminary report that showed that the number of games in a conference's regular season does not have a statistically significant correlation with a team's RPI.
"As conferences expand, they are faced with decisions about scheduling," Bowlsby said. "The commissioners have inquired about how their conference-scheduling philosophy affects the RPI. Intuitively, we thought there would be a correlation between the conference schedules in the RPI. Many commissioners and coaches believed that fewer conference games would result in a better RPI. But this initial data showed that's not true."
The initial study on the matter covered only three years, but the committee doesn't believe there will be any significant findings to contradict the research in the near future. But a five-year study will be done to provide more confirmation.
However, the newly weighted RPI may affect the conference-games issue.
"There's no way to know about that until we've gone through a couple of years with the new formula," Bowlsby said.
As part of its continuing effort to share the details of the selection and seeding process, the committee reaffirmed its principles and procedures, which are available to the public at www.ncaa sports. com.
Division I Men's Basketball Committee
November 30-December 2/Indianapolis