The NCAA announced significant changes to the NET formula used to help the NCAA Men’s Division I Basketball Committee select and seed the NCAA Tournament. Gone are the factors for winning percentage, weighted winning percentage and the capped margin of victory. The secret “Team Value Index” remains unchanged. The Net Efficiency component is now called Adjusted Net Efficiency and now factors in strength of opponent and game location. The TVI has those components as well, however they may have different impacts on each of the two components.
Here is what you need to know about the new NET and the impact on the selection process.
NCAA keeps formula a closely guarded secret
The secret formula is now even more secret. In fact, there is almost no part of the formula that can be calculated or reverse engineered. Only the base net efficiency can still be calculated.
My long-time readers know that I am not a big fan of secret formulas. It is unfair to teams to not know exactly how they are being judged. When rankings come out that intuitively do not make sense, there is nobody who can explain why that is, and that likely includes the committee itself. They are telling you that either you are not smart enough to understand this system in detail, or that you do not deserve to understand. Maybe both.
There are no plans to make any more parts of this formula publicly available.
Caps on Margin of Victory officially gone
There is no longer any pretense that Margin of Victory is capped, or even unimportant. Margin of Victory never was capped before because net efficiency is an analytics term for uncapped margin of victory and that was the second most weighted factor in the previous version of the NET. The difference is that net efficiency calculates MOV based on points per possession instead of points per game. And since possessions have to be estimated, they may not be exactly equal.
However, now it is the most weighted part of the formula. In fact, NCAA Director of Media Coordination and Statistics David Worlock said that this part is weighted “considerably” more than the TVI. For the first two years of the NET, the TVI was the most weighted part of the formula, reflecting the committee’s desire to put results over margin of victory. Now, that is reversed. Strength of schedule is still important and in some way part of both factors, but running up the score cannot be underrated.
Strength of Schedule will be changed
Strength of schedule rankings will still exist, both overall and non-conference, but those formulas have also changed. That is probably good, because they were still using the formula from the old RPI, and that was not very sophisticated. They will also still be important.
However, like everything else, the formula for this is a secret too. It is described thusly:
“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.”
I suspect we all have different definitions of “NCAA tournament-caliber team.” We will not see the NCAA’s definition of that.
The winning percentage, adjusted winning percentage and capped MOV parts of the old formula never made sense, so good riddance.
The quadrant system stays the same
This is the new ranking system for putting teams into quadrants on the team sheets. Those sheets are unchanged as well. No matter how sophisticated the ranking system gets, it is not designed to select and seed the teams for the committee. There will still be teams left out with good rankings and teams that get in with relatively poor rankings. The committee still doesn’t want a computer to do all their thinking for them.
A final thought. This is likely to skew even more to the power teams. That is just an educated guess, but the more important margin of victory becomes, the more that will benefit the power schools. It means they can still play some bad teams, but mitigate the SOS impact of that by running up the score as high as they can.
Also, it will be difficult to judge how the committee treats these rankings vs the old version of the NET because we only had one year of selections based on that. That is not a great statistical sample.