THE POWER RANK

The coaching bump in the NCAA tournament – how to use it for picking your bracket

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college_basketball_photoWhich coaches excel the most in the NCAA tournament?

Some coaches seem to take a cast off band of misfits and whip them into a machine that wins in March. These men must not only motivate players in all games but also make adjustments for new opponents with a short turn around time.

Here, we’ll look at which coaches outperform expectations. To set this baseline expectation, we’ll use types of predictors:

Care to guess which coach outperforms the most? Yes, Michigan State’s Tom Izzo does elevate his team to a new level during March Madness.

However, Izzo is not the coach that outperforms expectations the most between 2002 and 2015. Let’s look at the coaches on this list and the implications for winning your pool.

Tom Izzo

I started crunching these numbers because I didn’t think Tom Izzo had any quantifiable tourney magic. Back in 2015, he had led his 7 seed Spartans to an improbable Final Four and again became a media darling because of his tourney success. I thought it was small sample size bullshit.

I was wrong.

To evaluate the coaching bump, I compare the actual margin of victory in a game with a baseline expectation. For example, consider Michigan State’s 2015 tournament game against Virginia. My pre-tourney numbers expected Virginia to win by 6.2 points. Michigan State won by 6, so they exceeded expectation by +12.2 points.

The coaching bump is the average points by which a coach exceeds expectations, whether by my numbers or the markets. Over 44 tournament games from 2002 through 2015, Izzo has a coaching bump of 1.74 points over The Power Rank baseline.

To show the significance of this coaching bump, we resort to a t-test. This gives a 88.7% chance that Izzo’s performance is not due to randomness. It doesn’t quite reach the 95% level used in medical studies, but it still inspires confidence in Izzo’s coaching.

I also looked at Izzo’s coaching bump compared with the markets. His teams have outperformed these point spreads by 0.84 points. Note this also implies that the markets on average give Michigan State an extra point compared with my pre-tourney numbers.

Which coaches do better than Izzo?

Mike Krzyzewski

How about the coach with the most career wins?

No. Over a sample of 44 tournament games, Coach K’s teams have performed exactly at The Power Rank baseline (-0.01 if you must be exact). Duke has done -0.63 points worse than the markets.

This surprised me. I view Coach K as a people person that pushes the right buttons in motivating his players. However, it hasn’t worked in the tourney over the past 14 years.

Duke has had their successes, as they’ve won two titles (2010, 2015). However, they have also suffered three humiliating defeats in the Round of 64 (2007, 2012, 2014).

My methods for looking at the coaching bump suffers from small sample size, so perhaps Coach K has done better over a longer time horizon. The man does have 5 titles.

However, a study by FiveThirtyEight looked at how far a team advances in the tournament each year compared with expectation of seed and analytics. Even with data back through 1985, Coach K doesn’t appear near the top.

Rick Pitino

During his time at Louisville, Pitino has exceeded pre-tourney expectation. Oh wait, they’re on self imposed stripper probation this year.

Let’s move on.

John Calipari

How about the slick haired coach at Kentucky?

Since 2002, his teams have performed 2.47 points better than my pre-tourney numbers, better than Izzo’s Michigan State teams. These numbers include coaching stops at both Memphis and Kentucky.

Calipari has a 0.89 coaching bump over the markets. This suggests a substantial adjustment by the markets for Kentucky in the tournament, a factor with great implications this year.

Calipari’s “one and done” program at Kentucky provides a partial explanation for his coaching bump. He has embraced the modern world of college basketball in which the top talents leave for the NBA after one year.

It’s reasonable to think his freshman talent plays better towards the end of the season than the beginning. This maturation plays a role in Calipari’s coaching bump.

This year, Calipari’s Kentucky team has surged late in the season. According to the markets, they have the fourth best odds of winning the tournament behind Kansas, North Carolina and Michigan State.

However, Calipari doesn’t have the biggest bump based on my data. Who does?

Roy Williams

I was surprised to learn that North Carolina’s Roy Williams has given his team the biggest coaching bump for the tourney.

Since 2002, his North Carolina teams have performed 3.84 points better than The Power Rank’s pre-tourney numbers, by far the most. Over a sample of 51 games, the t-test implies a 99% confidence that Williams’ teams outperform expectation.

Williams has also outperformed the markets by 1.71 points. This implies that the markets have made an adjustment for his coaching but not quite enough.

Roy Williams isn’t known as a tournament coach. He’s a great recruiter that employs an up tempo style with great athletes.

Of course, this study is based on a limited sample size. Williams also coached Kansas before his tenure at North Carolina and disappointed in many tournaments. The FiveThirtyEight study with data back until 1985 doesn’t have Williams near the top.

If I could perform this study with more data, we might get different results for Williams. And this leads me to bracket advice based on this research.

How to win your March Madness pool

My win probabilities for the tournament, which you can play with in this interactive bracket, are based on the same pre-tourney numbers used in this study. Since some coaches outperform this baseline, it’s useful to make some adjustments to my win probabilities.

For example, my numbers give Michigan State a 10.2% chance to win the tournament. With the Izzo bump, it should be higher. The markets agree with this, as they have a one in five chance. This gives an implied probability of 12.1%.

For more advice on how to win your pool, check out my book How to Win Your NCAA Tournament Pool.

John Calipari is a better tournament coach than Tom Izzo

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calipariJohn Calipari evokes many different emotions in sports fans.

If you’re a Kentucky fan, you probably love Calipari. In six years as coach, he has won a national championship, and his 2015 team might win another with an undefeated record.

If you’re not a Kentucky fan, Calipari represents all that’s wrong with college basketball. His teams at Massachusetts and Memphis had to vacate wins during Final Four years because of NCAA rules violations. While the NCAA never found Calipari guilty of anything, it seems unlikely he knew nothing about the infractions.

Moreover, Calipari pisses off his colleagues. At a press conference, he got former Temple coach John Chaney so mad that Chaney attacked him, yelling “I’ll kill you.” Yes, this really happened; check out the video.

Numbers reveal a third side Calipari: he’s an amazing tournament coach. This article looks at how teams perform in the tournament compared with a regular season baseline. With a high degree of statistical certainty, Calipari’s teams play better in March than the regular season.

Calipari’s ability to get more out of his teams during the tournament is neither a typical part of his narrative nor the story in which I was originally interested. Michigan State coach Tom Izzo usually gets praised for his excellent coaching in March. I didn’t believe this conventional wisdom, so I dug into the numbers.

Comparing tournament performance with the regular season

To test Michigan State’s play in the tournament, I compared their margin of victory in the post season with expectations from the regular season.

For a regular season baseline, I used my college basketball team rankings at The Power Rank. Developed from my Ph.D. research in statistical physics, this algorithm takes margin of victory and adjusts for strength of schedule.

From 2002 through 2014, the higher ranked team in my pre-tournament rankings won 71.3% of games. In addition, the rankings provide a predicted margin of victory in each game. We’ll use this prediction as a baseline for tournament performance since, unlike the point spread in Vegas, it makes no preference for Michigan State or any other team in March.

For all tournament games from 2012 through 2015, I looked at Michigan State’s actual margin of victory compared with The Power Rank’s prediction. For example, in 2015, Michigan State beat Virginia by 6 points and exceeded the baseline prediction by 12.1 points. In 43 games tournament games, Michigan State has exceeded their expectation from The Power Rank by an average of 2.07 points.

Two points might not seem like a lot, but it’s a huge jump in performance. If the betting markets favor a college basketball team by 2 points, this teams wins the game 58.4% of the time, much more than the 50% for a game with a zero point spread.

Are these results statistically significant?

However, we can’t just assume that Michigan State performs better in the tournament based on this 2.07 points. There’s randomness in this estimate. We don’t know whether Michigan State performed at the same level as the regular season and got lucky by two points a game. Or Michigan State could be 4 points better than the regular season and got unlucky in the tournament.

Statistics gives us tools to account for the randomness in this estimate. A t-test, a method first developed at the Guinness Brewery, provides a probability that this estimate of 2.07 points is better than zero. This test, using this nifty calculator, gives a 92.6% confidence that Michigan State performs better in the tournament. (For those who want to check my work, the standard deviation of sample mean over 43 games was 1.40 points.)

I was wrong. The numbers suggests a high likelihood that Tom Izzo’s teams perform better in the tournament. Conventional wisdom wins this time.

The greatness of John Calipari

With the code to perform this test for Tom Izzo, I decided to repeat the test for the other Final Four coaches in 2015.

Duke coach Mike Krzyzewski has a reputation for getting the most of his players in March. However, since 2002, they have performed 0.41 points worse than The Power Rank’s expectation from the regular season.

Wisconsin coach Bo Ryan did slightly better than Krzyzewski in the tournament. However, his teams still performed 0.21 points worse than expected over 37 games.

John Calipari was a different story. During his years at Kentucky (2010 to present), his teams have performed 3.86 points better than their regular season expectation. Even with the smaller sample size than the other coaches (25 games), we can be 98.1% sure Kentucky has played better in the tournament.

Calipari also coached at Memphis before taking the Kentucky job. From 2002 through 2009, his Memphis teams exceeded their regular season expectation by 1.38 points in 20 tournament games.

It’s probably best to combine the tournament performances of Calipari’s Kentucky and Memphis teams, which gives a 2.76 point improvement over 45 games. That implies a 96.8% confidence that his teams play better in the tournament. In addition, Calipari’s tournament improvement is 35% larger than Tom Izzo’s improvement.

The following list summarizes the difference in tournament performance from the regular season since 2002.

  • John Calipari: + 2.76 points per game.
  • Tom Izzo: +2.04 points per game.
  • Bo Ryan: -0.21 points per game.
  • Mike Krzyzewski: -0.41 points per game.

For the 2015 Final Four, the main story should be John Calipari’s greatness as a tournament coach.