Explaining the NET system and how it impacts WSU’s tourney chances

After its first five-game winning streak in Pac-12 play since the 2006-2007 season, Washington State men’s basketball has finally made it onto the NCAA tournament bubble, according to ESPN bracketologist Joe Lunardi. WSU’s March Madness resume is generally devoid of any eye-popping wins that bracketology loves but its current No. 36 NET ranking likely has it on the radar of Lunardi, other bracketologists, and the NCAA tournament selection committee.

NET, which stands for NCAA Evaluation Tool, replaced RPI as the committee’s primary evaluation metric in men’s basketball beginning with the 2018-2019 season. It has evolved slightly since its initial launch and this is how the NET is officially described by the NCAA:

The NET has two components: the Team Value Index, which is based on game results and factors the result, the game location, and outcome. The other component is net efficiency (offensive efficiency minus defensive efficiency), which is adjusted to account for the strength of the opponent and the location of the game.

The Difference Between the NET and RPI

How does the NET differ from RPI? There are two primary differences. First, the NET actually factors in the location of games played, giving different weights for home, away, and neutral site contests. Second, while the Team Value Index does factor in wins and losses as RPI did, the adjusted net efficiency is the massive change.

Adjusted net efficiency, also called adjusted efficiency margin, is how KenPom evaluates and ranks teams, and that is what largely influenced the switch to NET. Efficiency margin takes how many points a team scores per 100 possessions and subtracts how many points it allows per 100 possessions.

This changes how teams are evaluated because it eliminates the binary value of each game, assigning more of a sliding scale value. A one-point WSU win is not as valuable as a 15-point WSU win. The NET does cap margins, as does KenPom.

The difference between NET and KenPom, aside from potential coefficients in the formulas, is that KenPom does not take into account wins or losses—it merely evaluates based on efficiency margin.

The reason for this is that KenPom is meant to be a predictive tool rather than a resume evaluation tool. The NET acts as both, and that creates slight differences. The Cougs currently sit at No. 33 on KenPom and No. 36 in NET.

Where would WSU be if the old RPI system was still used? Wazzu would be sitting at 74th, according to CBS Sports. This illustrates the impact of adjusted efficiency margin. In the RPI system, WSU’s 27-point win over Colorado would carry the same weight as its 5-point loss Colorado. In the NET, the Cougs get more credit for the big win and are punished less for the narrow loss.

The seven losses on WSU’s resume are by a combined 29 points, while many of the Cougs’ wins have come by double digits. That imbalance gives Wazzu an overall positive efficiency margin and that’s why the NET ranks them so much higher than RPI.

How does the NCAA tournament selection committee use NET?

The NCAA describes the NET as one of many evaluation tools that tournament selection committee members use. It’s also possible that some committee members value it more than others. However, it does provide a baseline ranking that can help narrow down their list of potential NCAA tournament teams.

The committee also looks at other factors beyond the NET, such as key players missing games and travel challenges, as well as other metrics like KenPom. It also puts emphasis on quality wins, and that is why it created the quadrant system for categorizing the value of specific wins and losses.

The NET quadrant system puts each game into a box based on team ranking and location. There are four quadrants and they break down as such:

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 quadrant system for evaluating wins is why WSU is still on the outside of most tournament projections. The Cougs have played just two Quadrant 1 games (USC and Boise State) and lost them both. While WSU has the NET ranking of a tournament team, in all likelihood it still needs to add some Quadrant 1 victories to its resume for at-large selection.

There will be many Quadrant 1 opportunities for WSU before the start of the Pac-12 tournament: Arizona at home along with Oregon, UCLA, and USC on the road. It would be of serious benefit to WSU’s NCAA tournament chances to win a couple of those games.

What are WSU’s chances of adding Quadrant 1 wins?

While WSU’s NET and KenPom rankings certainly put it on the radar of the NCAA tournament selection committee, they also provide a reason for optimism. These ranking systems are meant to be predictive, especially in the case of KenPom. WSU’s rankings mean they are probably good enough to compete with the Quadrant 1 teams on their schedule.

Currently, KenPom gives WSU a 29% probability to beat Arizona, 44% probability at Oregon, 22% at UCLA, and 37% at USC. Those probabilities cumulate to 1.32 Quad 1 wins expected.

Obviously, those probabilities predict WSU to lose in each game, but that’s the beauty of probabilities: they offer a range of possibilities. KenPom thinks the Cougs win 29 times out of 100 against Arizona. That’s far from a long shot.

If you want to drink some deeper crimson Kool-Aid, check out Bart Torvik’s ranking system. Torvik’s formula ranks the Cougs at No. 17. It gives WSU a 43% chance to beat Arizona, 43% to beat Oregon, 25% at UCLA, and 46% at USC. That adds up to 1.57 expected wins in that highly important subset of games.

Torvik’s system is like KenPom’s old Pythagorean ranking system before KenPom transitioned to adjusted efficiency margin. The key difference that gives WSU a boost is Torvik’s incorporation of a game-state metric that evaluates a team’s average margin throughout a game—meaning the Cougs are getting credit for the many big leads that turned into smaller wins or losses on their ledger.

Based on predictive systems, the Cougs are expected to win between one and two of their four Quad 1 NET opportunities. If WSU outperforms expectations slightly with two Quad 1 victories while winning most or all of its Quads 2-4 games remaining that would likely set it up on the right side of the NCAA tournament bubble.