Sunday, January 31, 2016

Home Court Advantage: Free Throw Shooting

The King emerges from behind Arizona State's
"Curtain of Distraction"
This is the first in a series of posts on home court advantage in the NBA. Each post will examine home court advantage from a specific statistical angle.

Home court (and home field) advantage may be one of the most documented and replicated phenomena in the field of psychology. It shows up in every major sporting competition: soccer, football (professional and collegiate), baseball, college basketball, and the NBA. There is a wealth of statistics supporting its existence, literally spanning three centuries.

Since 2010, home teams in the NBA have won 59% of their games, with an average point differential of 2.8 points. While home court advantage has been on the decline, relative to the veritable coach and buggy days of the 1970's (see this chart from ESPN's Tom Haberstroh), rumors of its eventual demise may have been exaggerated.

At this point in the season last year, home teams had an all-time low winning percentage of just 53.7%. It appeared we were in the midst of a home court advantage sea change. NBA teams were finally winning the road battle, thanks to advanced biometrics, disinterested crowds, and sweet, sweet chartered jets.

Saturday, January 23, 2016

San Antonio's stinginess in transition

The San Antonio Spurs currently lead the league in defensive efficiency, allowing just 95.3 points per 100 possessions, according to Basketball Reference. With the league averaging 105.1 points per 100 possessions overall, the Spurs are ten points above the league average on defense. They are better at defense than the Warriors are on offense, as Golden State is currently nine points above the league average, with 114.3 points per 100 possessions.

To illustrate what an outlier the Spurs are on defense, I will use the advanced per possessions statistics tool to examine the Spurs' defensive efficiency and what drives it. Here is a chart for overall defensive efficiency (note that these numbers differ slightly from basketball reference, due to oddities in the play by play data and the exclusion of technical foul points).

Wednesday, January 6, 2016

The Vegas Playoffs

Inspired by numbers shared by Cousin Sal on Monday's Bill Simmons podcast (and idle curiosity), I decided to reseed the NFL playoff field according to record against the spread, as opposed to win-loss record. There is literally no point to this exercise, but when you have spent hours coding the NFL's excessively redundant tiebreaking procedures like I have, you're on the lookout for any way to justify your time down in that hole.

Here is the AFC Vegas playoff field:

Sunday, January 3, 2016

Heroes, Goats and Garbage Men : New Clutch Shooting Reports

Clutch shooting isn't easy, and neither is defining it. The NBA defines clutch shooting as any shot taken in the last five minutes of the game in which the score differential is within five points. For this post, I will introduce a new interactive tool that uses my win probability model to classify shots into four categories: Garbage Time, "Normal" Basketball, Clutch Situations, and "Double Clutch" situations. With these four new shooting categories, we can dive deep into which players are taking and/or making the most clutch shots.

As I called out in a previous post on clutch performance, there is nothing inherently wrong with the NBA's definition of clutch performance. There's something to be said for easily applicable rules that are simple to explain. However, a shot taken in the final minute when your team is up by five doesn't feel quite as "clutch" as a three pointer in the final 10 seconds with your team trailing by two. Fortunately, we can use win probability to create a more nuanced version of clutch, and one that better aligns with what one would expect a clutch situation to be.