A few days back I wrote about the relationship between the NCAA’s new, proprietary method of ranking college basketball teams called NET, and the traditional measure of team strength known as RPI. The two were unsurprisingly closely matched, but there were some strong disparities between the two measures when it came to certain teams like Kansas.
Since the two measures are not perfectly correlated, they might have played separate roles in the Committee’s decision-making process when seeding the field last Sunday. In addition, I showed in that earlier article that the NET methodology already had a built-in bias toward teams in the six major conferences. The Committee has always favored teams from the major conferences and seeded them higher than teams from other conferences with the same RPI score. If the new NET score already benefits major-conference teams, did they also get their traditional bonus from years past, in effect a “double bonus?”
To answer this question I estimated a slightly different version of the model I’ve used before to predict seedings. I include RPI and major conference memberships once more, but this time I added the NET measure as well. Because NET is simply a ranking taking its logarithm improves the fit. So this model asks whether both NET and RPI had independent influences on seeding position, and whether major-conference teams still received a bonus. Here are the results (again using Tobit with censors at one and sixteen):Even with just sixty teams, all three factors prove “significant.” Of the three coefficients in the first column, only the one for major conferences has an intuitive meaning. Teams from those conferences were seeded nearly two (1.9) ranks above teams from other conferences with identical scores on RPI and NET ranking.
A more useful comparison comes in the “standardized” coefficients, which adjust for differences in the variation of the different measures used. By this measure, the most important factor by far in seeding decisions this year was NET. However, at the margins, RPI played a role as did whether the team came from a major conference.
While the “double bonus” is statistically measurable, it does not seem to have affected the distribution of at-large bids. Half the field, 32 teams, receive automatic bids because they have won their conference tournaments. The other half are selected by the Committee to receive an at-large bid. During the ESPN discussion show following the draw on Sunday night, famed basketball commentator Dick Vitale complained that the Committee was awarding too many at-large bids to teams from major conferences. Might NET have been responsible for that?
There was a slight uptick in the number of at-large bids given to major-conference teams this year, but that has been the trend since 2012. If NET was responsible for closing out smaller schools, it had a very limited impact compared to the trend.