Will a 16 seed ever beat a 1 seed?

That question arose during a recent dinner with my friend Graham at a popular pizza restaurant in Seattle. Tony Kornheiser of PTI said last week that it will never happen. Graham agrees. I think it will happen in our lifetime. It has almost happened a number of times already.

It seemed to me from casual observation like 16 seeds are getting closer to winning on average, but I decided to check this by plotting the point differential of higher-seeded teams during the first round of the NCAA tournament (in the first round there are four 1-vs-16 games). Indeed, compared to many other matchups the 1-vs-16 matchup has shifted greatly over time.

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The margin of victory is still substantial, between 10 and 15 points so far this decade, but I remain confident that, let’s say, sometime in the next 40 years it will happen.  There have already been eight 15 seed victories over number 2 seeds and twenty-one 14 seed wins over 3 seeds. The situation looks even better when you consider the closest 1-vs-16 game during each tournament (since we only need one 16 seed to win).

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It seems that about two to three times every decade there are relatively close 1-vs-16 games and about once a decade there is an extremely close game (decided by just a couple of points). The 2000s did not fare well for 16 seeds.

I think the outcomes of close games are more stochastic than most. Leadership attribution bias seems to turn these stochastic events into narratives of late-game heroics and we’re prone to say that the 1 seed is more poised and resistant to pressure than players at smaller schools. Of course the history of the tournament has shown us many, many exceptions to this rule (if it’s a rule at all). At tension with this narrative is the story of the underdog that is just happy to be at the tournament and has nothing to lose, playing loose, having fun, and playing “to win” while the nervous champion is playing “not to lose.” So to me many of these games are closer to a coin flip than we like to think and given enough coin flips a tail is bound to come up eventually.

Also, think about it this way: How much difference is there between a 1 seed and a 2 seed, and between a 15 seed and a 16 seed? As you know if you ever watch the tournament seeding show there isn’t much of a difference. The lowest ranked number 1 seed isn’t much better – and could be worse – than some of the number 2 seeds, and eight times has a two seed lost in the first round. Of course you could argue the 2 seeds that lost should have actually been 3 seeds, although this year Michigan State lost as a number 2 seed and many considered them to be a favorite in the entire tournament (by some measures this is the biggest tournament upset ever). The larger point is that seeding is also somewhat stochastic and the question “can a 16 seed beat a 1 seed” is really the question of whether an overmatched team can exhibit a one-time victory over an opponent that is much more dominant on average. And we already know the answer to this question is “yes.”

To give the other side its due, since 1979 when seeding began, 22 of the 37 NCAA Tournament winners have been 1 seeds, so at least some of the top seeds are properly ranked and 16 seeds will have a tough time beating them when ranking is accurate.

It’s also a question as to why the decrease in point margin has occurred. Keep in mind the plot above is just a second-order trend line, although if you plot the underlying year-by-year margin it does follow the trend on average (of course). It’s interesting that the late 1980s and early 1990s was a time of lower point differential for 16-vs-1 games and that this period also correlated with three wins for 2 seeds in the first round (1991, 1993, 1997). Likewise the past few years have seen another decrease in 16-vs-1 game point differential and another string of 2-seed wins, two in 2012 and one each in 2013 and 2016. Similarly, between 1986 and 1999 there were thirteen times that a 14 beat a 3, and since 2010 this has occurred another six times (the intervening years saw only two instances of this in 2005 and 2006). These two periods also correspond to the highly touted recruiting classes of Michigan in 1991 (famously nicknamed the “Fab Five“) and Kentucky’s 2013 “mega class.” It may be that there are episodic shifts in recruiting that systematically leave certain types of talent on the table for smaller schools to cull and develop. (Of course, it may be I’m just seeing patterns where none exist).

My recent memory is that although there are a few good schools that still get the best players, smaller schools have seen that if they recruit good players (particularly good shooters or traditional big men) and play as a team they have a chance at beating anyone in the first rounds and perhaps going deep into the tournament. This increases their confidence and performance. This is another reason I think a 16 seed will eventually beat a 1, because the recent years of the tournament have expanded our imagination of what is possible. Think about the well-known phenomenon of a 12 seed always beating a 5 seed. How nervous do you think 5 seeds are every year? How much of this consistency in a 12 beating a 5 is self-reinforcing and due to the 5 seeds having “the jitters” and the 12 seeds being relatively overconfident?