When people think of March Madness, they often focus on the men’s tournament because of its history of Cinderella’s making deep runs into the tournament (ie. Loyola-Chicago this year). There seems to always be an unpredictable upset every year. This year, the men’s tournament’s first round saw UMBC defeat Virginia, only the second time in tournament history that a 16 has defeated a 1 seed. The first time occurred when Harvard defeated Stanford 20 years ago in the women’s bracket. Despite this unlikely upset, the women’s bracket has become known for its lack of randomness. For example, in 1999, the top 16 seeds made it to the Sweet 16. In addition, only 2 number 1 seeds have been eliminated before the Sweet 16 since Harvard knocked off Stanford.
Recently, Fivethirtyeight wrote an article suggesting that the other teams are catching up to UConn; however, this focused on other top teams like Baylor. In this year’s tournament, both Buffalo and Central Michigan have made the Sweet 16. This is the first time that 2 double digit seeded mid-majors have made the Sweet 16 this century since 1996. Thus, I was curious to see if the women’s half of the bracket has actually become more prone to upsets.
To do this, I looked at the past 20 tournaments through the Sweet 16 (1999-2018). First, I calculated the sum of seeds that made the Sweet 16 and the number of upsets (I considered any lower seed winning to be an upset). Finally, I calculated the total difference in seeds for upset wins for each year. We can see plots of all 3 below.
Next, to see if there has been a significant increase in each of the 3 measures over the past 20 years, I ran a linear regression. We found none of the 3 to be significant at the 5% level despite seeing a positive trend over the past 20 years. As such, we cannot reject the null hypothesis that the level of upsets has increased. However, this data is certainly encouraging and does indicate that the tournament is becoming more balanced. This year, 2018, actually has the highest sum of difference in seeds in upsets and is tied for the most upsets in this dataset. While UConn and the other elite programs may still be prohibitive favorites, we can tentatively say that other teams will have a reasonable chance of busting everyone’s brackets in the not so distant future.
Editors Note: If you have any questions about this article, please feel free to reach out to Chase at firstname.lastname@example.org