The NCAA Tournament Network

By John Ezekowitz and Ben Blatt

Now that the bracket is out and fans everywhere are busy trying to find that perfect upset, a lot of attention will be paid rightly to projecting ahead. We thought, however, that it might be nice to take a moment and look at what we have already. The NCAA Tournament bracket represents the culmination of an entire college basketball season, and holds a lot more information than it might appear on first glance.

For instance, we can use the NCAA Tournament bracket to illustrate just whom the best teams have played, beaten, and lost to in college basketball this year. We can do this using graphical techniques and analysis from the field of network analysis.

Who Beat Whom? A Network of the Top 8 Seeds

In this network, the teams are the nodes (the size of the nodes are weighted by the seed with one seeds being the largest), and the vertices are games played between two teams. Arrows pointing at a team represent losses to other teams in the upper half on the NCAA Tournament, lines going out represent wins. Connections with two arrows (Duke and North Carolina) mean that both teams beat each other over the course of the year. We had tried to do this graph for all 68 teams, but it was hopelessly confusing.

What does this tell us? It is clear that Big East teams had the most opportunities against teams in the top 32 of the seeding. That does not mean that they necessarily have more wins against these teams than teams from other conferences. St John’s, for instance, lost to no fewer than six top eight seeds. Ohio State, the overall number one seed, has only lost games to top four seeds, and has beaten every team that they have lost to.

Two teams at the bottom may be of interest. San Diego State and Florida are both two seeds, but do not have many wins over top 32 teams. SDSU’s might be because of a lack of opportunity (they only played two this year, BYU and UNLV), but Florida’s is more puzzling.

This may not help you with your bracket, but it is a cool way of understanding the NCAA Tournament Network.