What's the difference between RPI and NET? The NCAA has a new primary evaluation tool when it comes to selecting and seeding the men's NCAA tournament.
The NCAA Men's Basketball Committee is adopting a new ranking system to replace Rating Percentage Index (RPI) as its primary evaluation tool in evaluating Division I men's basketball teams, the league announced.
The NCAA Evaluation Tool, or NET, will rely on game results, strength of schedule, game location, scoring margin, net offensive and defensive efficiency and the quality of wins and losses.
Up-to-date 2018–19 NET rankings can be found here.
In late July, use of the NET model was approved following several months of consultation between the Division I Men's Basketball Committee, the National Association of Basketball Coaches, top basketball analytics experts and Google Cloud Professional Services.
The system was optimized through a trial period during the late portion of the 2017-18 regular season and NCAA tournament. Results from several games were used as test sets to create a system that leveraged the machine's learning techniques.
In order to "ensure fairness" components such as game dates, the order in which contests are placed was omitted from the development of NET, making early- and late-season equal in importance. The model also caps winning margins at 10 points in accounting for the event of a blowout score.
“What has been developed is a contemporary method of looking at teams analytically, using results-based and predictive metrics that will assist the Men’s Basketball Committee as it reviews games throughout the season,” Dan Gavitt, the senior vice president of basketball for the NCAA, said in a statement. “While no perfect rankings exist, using the results of past tournaments will help ensure that the rankings are built on an objective source of truth.”
In November, the NCAA revealed the five factors that NET will include in its calculations: Team value index, net efficiency, winning percentage, adjusted win percentage and scoring margin.
NET is the second significant change the committee has made to its evaluation process in as many seasons. This past year saw the introduction of the quadrant system, a ranking tool which placed greater emphasis on successful neutral and away games. The system will factor into the committee's evaluations.
Along with NET and the quadrant system, here are the other criteria the committee considers during the selection process:
- An extensive season-long evaluation of teams through watching games, conference monitoring calls and regional advisory committee rankings;
- Complete box scores and results;
- Head-to-head results and results versus common opponents;
- Imbalanced conference schedules and results;
- Overall and non-conference strength of schedule;
- The quality of wins and losses;
- Road record;
- Player and coach availability; and
- Various computer metrics.
The RPI was introduced in 1981. While it will no longer be used to determine the NCAA men's basketball tournament field, other Division I sports committees, including the women's basketball committee, will still utilize the metric next season.