The 2021-22 men's basketball season marks the fourth season of the NCAA Evaluation Tool (NET) rankings, which replaced the RPI prior to the 2018-19 season as the primary sorting tool for evaluating teams. In May 2020, the NCAA announced there will be changes made to the NCAA Evaluation Tool to increase accuracy and simplify it by reducing a five-component metric to just two.
The remaining factors include the Team Value Index (TVI), which is a result-based feature that rewards teams for beating quality opponents, particularly away from home, as well as an adjusted net efficiency rating. The adjusted efficiency is a team’s net efficiency, adjusted for strength of opponent and location (home/away/neutral) across all games played. For example, a given efficiency value (net points per 100 possessions) against stronger opposition rates higher than the same efficiency against lesser opponents and having a certain efficiency on the road rates higher than the same efficiency at home.
We're here to help you understand what's valued in the NET rankings and how they're used.
What did the RPI calculate? How is the NET different?
The Ratings Power Index (RPI) was made up of three components:
- A team's winning percentage
- Average opponent's winning percentage
- Average opponent's opponent's winning percentage
The NET includes more components than just winning percentage. It takes into account game results, strength of schedule, game location, scoring margin, net offensive and defensive efficiency, and the quality of wins and losses.
It's both a results-driven and predictive metric.
What are the NET Rankings?— NCAA March Madness (@marchmadness) November 26, 2018
Here's EVERYTHING you need to know. Be on the lookout for the first release pic.twitter.com/kdZwDEjFPS
How was the NET rankings system created?
The NET rankings system was improved in the summer of 2018 after consultation with the Division I Men’s Basketball Committee, the National Association of Basketball Coaches, top basketball analytics experts and Google Cloud Professional Services.
Late-season games from the 2017-18 season, including from the NCAA tournament, were originally used as test sets to develop a ranking model that used machine learning techniques. The model was used to predict the outcome of games in test sets and it was optimized until it was as accurate as possible.
That model is the one used for the NET.
Is there any notable data not included in the NET?
Game date and game order were not included in the NET rankings so a team's first game counts the same as its 30th.
With the changes announced in May 2020, the NET will no longer use winning percentage, adjusted winning percentage and scoring margin. The change was made after the committee consulted with Google Cloud Professional Services, which worked with the NCAA to develop the original NET.
“When we adopted the NET in 2018, we had reviewed several seasons worth of data and we insisted that we would continue to evaluate the metric,” said Dan Gavitt, the NCAA’s senior vice president of basketball. “We’ve been very satisfied with its performance thus far, but it became evident after two seasons of use that this change would be an improvement. While we will continue to monitor the metric, I don’t anticipate any additional adjustments for several years. We believe this change will result in more precision throughout the season and will be easier for our membership and the public to understand."
The updated NET is consistent with the women’s basketball NET, which was revealed after the Division I Women’s Basketball Committee worked with a team from Google Cloud to evaluate women’s basketball statistical data for a 10-year period.
In addition, the overall and non-conference strength of schedule has been modernized to reflect a truer measure for how hard it is to defeat opponents. The strength of schedule is based on rating every game on a team's schedule for how hard it would be for an NCAA tournament-caliber team to win. It considers opponent strength and site of each game, assigning each game a difficulty score. Aggregating these across all games results in an overall expected win percentage versus a team's schedule, which can be ranked to get a better measure of the strength of schedule.
How are the NET rankings used?
Since the NET rankings serve as the primary sorting tool for Division I men's basketball, they play an important role in establishing a team's resume. The men’s and women’s basketball NET rankings and team sheets will be provided publicly on a daily basis on NCAA.com and NCAA.org starting in December.
Using the quadrant system, which was in its fourth season in 2020-21, the quality of wins and losses will be organized based on game location and the opponent's NET ranking.
- Quadrant 1: Home 1-30, Neutral 1-50, Away 1-75
- Quadrant 2: Home 31-75, Neutral 51-100, Away 76-135
- Quadrant 3: Home 76-160, Neutral 101-200, Away 135-240
- Quadrant 4: Home 161-353, Neutral 201-353, Away 241-353
The number of Quadrant 1 wins and Quadrant 3/4 losses will be incredibly important when it comes time for NCAA tournament selection and seeding.