Information You Need to Know to Help You Build Your Bracket in 2019

Building a bracket is easy.  Building a perfect bracket is effectively impossible, so you are not likely to achieve such a lofty goal. With 68 teams, there are 147,573,952,589,676,412,928 possible brackets (if one only considers the 64 teams in the main bracket, excluding the First Four. the number drops to 9,223,372,036,854,775,808). Since not all brackets are equally likely, the odds of creating a perfect bracket are better than these numbers indicate, albeit still quite remote. That being said, even building a good bracket is challenging.  It is difficult to imagine teams seeded No. 1, No. 2, or No. 3 losing early in the tournament, yet they do, with great regularity.  The challenge is deciding which of (and when) these seeds will lose. However, there are some patterns that have consistently emerged to help you avoid a bad bracket.

In the round of 64, the 5-12 upset gets a great deal of attention. In the 34 tournaments from 1985 through 2018, the No. 12 seeds had a 47-89 record. In fact, in 14 of the past 34 tournaments, two or three No. 12 seeds advanced to the round of 32. What gets less attention is the 6-11 upset. In the 34 tournaments from 1985 through 2018, the No. 11 seeds had a 51-85 record. Moreover, in 16 of the past 34 tournaments, two, three, or all four No. 11 seeds advanced to the round of 32. Collectively, an average of 4.58 teams seeded No 11 or lower (worse) advanced to the round of 32. Also, in 26 of the past 34 tournaments, four or more teams seeded No 11 or lower (worse) advanced to the round of 32. However, an average of 1.70 teams seeded No. 13 or lower (worse) have won in this round, so picking one such upset is prudent. Also, in 2018, a No. 16 seed defeated a No. 1 seed, the first such occurrence in the Men's tournament. Can we expect it to occur regularly? No one can predict the when, but we now know that the "if" is indeed possible.

How should your upsets be distributed in the round of 64? Eliminating the discussion on the 8-9 matchup, which is essentially a toss-up game (the No. 8 seed owns a 68-68 record), 25 out of 136 regions (18%) over the past 34 tournaments has had all of the top seven seeds advance. Moreover, in 43 out of 136 regions (32%) over the past 34 tournaments, exactly six of the top seven seeds have advanced, while in 49 out of 136 regions (36%) over the past 34 tournaments, exactly five of the top seven seeds have advanced. In only in 9 out of 136 regions (7%) over the past 34 tournaments have exactly four of the top seven seeds have advanced, while in 10 out of 136 regions (7%) over the past 34 tournaments, exactly 3 of the top seven seeds have advanced. Therefore, upsets should be spread thinly across the regions. If you feel really lucky, have one region "blowup".

In the round of 32, teams seeded No. 7 and worse continue to advance. In 30 of the past 34 tournaments, two or more of these teams have reached the Sweet Sixteen, with an average of 3.56 of these teams reaching this round. In fact, only once (1995) in the past 34 tournaments has there not been a team seeded No. 7 or worse reaching the Sweet Sixteen. Moreover, an average of 1.50 teams seeded No. 11 or worse reached the Sweet Sixteen, and in 30 of the past 34 tournaments, one or more of these teams reached the Sweet Sixteen. Among highly seeded teams, in 24 of the past 34 tournaments, 8 or fewer teams seeded No. 1, No. 2 or No. 3 reached the Sweet Sixteen.

The Final Four draws the most attention. The following table gives the probabilities for the number of No. 1 seeds that reach this round, based on our model.

P(Zero No. 1) 0.176
P(One No. 1) 0.383
P(Two No. 1) 0.312
P(Three No. 1) 0.114
P(Four No. 1) 0.015

It is over 11 times more likely for a Final Four to contain zero No. 1 seeds than it is to contain four No. 1 seeds. Picking one or two No. 1 seeds in the Final Four is prudent.

Some interesting factoids that may help you set your Final Four:

The odds against one or more No. 16 seeds reaching the Final Four is 477 to 1.
The odds against one or more No. 15 or No. 16 seeds reaching the Final Four is 187 to 1.
The odds against one or more No. 14, No. 15, or No. 16 seeds reaching the Final Four is 96 to 1.
The odds against one or more No. 13 through No. 16 seeds reaching the Final Four is 55 to 1.
The odds against one or more No. 12 through No. 16 seeds reaching the Final Four is 34 to 1.
The odds against one or more No. 11 through No. 16 seeds reaching the Final Four is 20 to 1.  This has happened four times over the past 34 tournaments (1986, 2006, 2011, 2018).
The odds against one or more No. 10 through No. 16 seeds reaching the Final Four is 12 to 1. 
This has happened five times over the past 34 tournaments (1986, 2006, 2011, 2016, 2018).
The odds against only teams seeded No. 3 or lower (worse) reaching the Final Four is 31 to 1.  This has happened once over the past 34 tournaments (2011).
The odds against only teams seeded No. 1, No. 2, or No. 3 reaching the Final Four is 2.5 to 1.  This has happened 11 times over the past 34 tournaments (1989, 1991, 1993, 1994, 1998, 2001, 2003, 2004, 2007, 2008, 2009).
The odds against only teams seeded No. 1 or No. 2 reaching the Final Four is 7.8 to 1.  This has happened 3 times over the past 34 tournaments (1993, 2007, 2008).

Enjoy filling out your bracket and watch the upsets unfold. Let the games begin!

 

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