NCAA football ranking variablity
Massey collects a bunch of different college football rankings. Below I’ve plotted the mean of these rankings on the x-axis and the standard deviation on the y-axis. There is very little variability among the rankings for the teams at the very top and very bottom. But in the middle, the variability is much larger. The color of the circle represents the conference and the size of the circle corresponds to wins.
Let’s consider some of the interesting cases. The team with the largest variability is Northern Illinois. Their mean rank is 62 and are ranked as high as 23 and as low as 95. Northern Illinois is 8-2 in the MAC and basically no one has any idea what to do with them. They have some wins over bigger conference football teams such as Northwestern (who just beat Notre Dame somehow) and UNLV. Their two losses are to Arkansas and Central Michigan. They are indeed and very confusing team to rank.
Marshall is another interesting case. Yes, they are undefeated, but they haven’t exactly played the most difficult schedule (#understatement). Some ranking called the Nolan Power index has them ranked 2 (behind Ohio State ?!?!). They are also ranked as low as 37. No one ever seems to know what to do with these undefeated teams that play terrible schedules.
Arkansas is the highest variability team of the major conferences. They are 5-5 but all five of those losses came against teams that were ranked top 10 at the time they played (Auburn, Texas A&M, Alabama, Georgia, and Mississippi State). Their big win before this week was Northern Illinois. And just this past week, they beat LSU. That is indeed confusing. As a result they are ranked as high as 10 and as low as 76 with an average of about 31.