Court Symmetry and Offensive Strategy:

One interesting thing I noticed when looking through various players’ shot charts that I created using data from the NBA’s SportVU player tracking cameras is that LaMarcus Aldridge takes a lot of shots from the left side of the court relative to the right:

LaMarcus Aldridge shot chart. Bigger circles indicate more shot attempts from that area

Regardless of whether it is preference or strategy as the reason for this many shots from one side of the court, opposing teams can use these tendencies in order to set their defensive schemes – for example, if a team favors the right side of the court, you can place your best defenders on that side of the zone. Over time, I would think that playing the odds like that can only help and not hurt.  It’s a bit like counting cards in black-jack.

In order to assess this phenomenon, I looked at the data on a league, team and player level (player analysis coming next week). An important metric that I will cite is the idea of an X-value. In terms of coordinate geometry, if the court is an (X,Y) plane, an X value of 0 is the center of the court, an X value of -25 (feet) is the far right sideline, and an X value of 25 (feet) is the far left sideline.

League:

As a league, there is a slight favor towards the right side of the court. The average x-axis value of the 95,419 field goals attempted between 10/28/14 and 1/13/15 is -.003 feet, which on the surface I thought indicated about an equal number of shots from the left and right side of the court. But what is interesting is that when you break it down into percentage of shots taken from each side of the court, it is a skewed towards the right:

FGA by Shot Location

	Left	Center	Right
NBA (percentage)	40.7%	14.4%	44.9%
NBA (number)	38,845	13,762	42,812

Essentially we are dealing with a weighted average – in basketball terms what this means is that while there are more shots coming from the right side of the court than the left, the shots that are coming from the left side of the court are coming from further to the left than the shots from the right side of the court are to the right. And when we analyze the data further – it reveals this to be exactly the case:

Pull to Side by Shot Location

	Left	Center	Right
Average X value by side	9.75 feet	0 feet	-8.85 feet

So the conclusion here is that teams tend to favor the right side of the court relative to the left, but take shots further from the center on the left side of the court than the right. To some extent, this makes sense to me – players like to drive with their dominant hand, which for most players is their right, and thus you see not only more shots from that side, but closer shots.

Team:

The data from the team level analysis shows that 22/30 teams favor their right relative to their left, some to an extreme degree – such as the Nuggets. The teams that favor their left on average more heavily favor that side than the teams that favor the right do in favoring the right side. Below is a table of the data, and below that are a few sample team shot charts to help visualize this skew:

Team	Left	Center	Right	Left/Right Delta	Favor
Denver Nuggets	35.83%	14.30%	49.87%	14.05%	Right
Dallas Mavericks	36.83%	14.89%	48.28%	11.46%	Right
Atlanta Hawks	37.28%	14.15%	48.57%	11.29%	Right
Brooklyn Nets	38.58%	12.34%	49.08%	10.50%	Right
San Antonio Spurs	38.98%	12.04%	48.98%	10.00%	Right
Washington Wizards	37.89%	14.99%	47.12%	9.22%	Right
New York Knicks	39.82%	11.28%	48.90%	9.08%	Right
Boston Celtics	38.18%	14.76%	47.06%	8.89%	Right
Miami Heat	40.61%	11.28%	48.11%	7.50%	Right
Indiana Pacers	40.70%	11.45%	47.84%	7.14%	Right
Utah Jazz	38.84%	15.18%	45.98%	7.14%	Right
Orlando Magic	38.94%	16.37%	44.69%	5.75%	Right
Memphis Grizzlies	40.06%	15.30%	44.64%	4.57%	Right
Phoenix Suns	41.58%	12.34%	46.09%	4.51%	Right
New Orleans Pelicans	40.98%	13.98%	45.04%	4.06%	Right
Golden State Warriors	40.72%	15.59%	43.69%	2.98%	Right
Chicago Bulls	42.67%	12.11%	45.22%	2.55%	Right
Charlotte Hornets	43.15%	11.33%	45.52%	2.36%	Right
Sacramento Kings	41.99%	13.85%	44.16%	2.17%	Right
Los Angeles Clippers	41.91%	14.15%	43.94%	2.03%	Right
Toronto Raptors	42.55%	12.88%	44.57%	2.03%	Right
Houston Rockets	41.89%	14.26%	43.85%	1.96%	Right
Los Angeles Lakers	43.24%	14.05%	42.71%	-0.53%	Left
Oklahoma City Thunder	42.54%	15.72%	41.74%	-0.80%	Left
Minnesota Timberwolves	42.29%	16.37%	41.34%	-0.95%	Left
Philadelphia 76ers	42.62%	16.09%	41.29%	-1.34%	Left
Cleveland Cavaliers	42.17%	18.13%	39.69%	-2.48%	Left
Detroit Pistons	40.60%	21.46%	37.94%	-2.66%	Left
Milwaukee Bucks	41.64%	20.41%	37.95%	-3.69%	Left
Portland Trail Blazers	46.03%	11.85%	42.11%	-3.92%	Left

Two opposite ends of the spectrum – Nuggets favor the right more than the left, Trail Blazers favor the left relative to the right, but with much less skew to the left than the Nuggets have to the right.

It’s a bit hard to tell, but for the Nuggets it appears that a fair amount of the skew towards the right comes in the paint in addition to the right elbow region. For the Blazers, the skew towards the left appears to be rooted in baseline shots and corner 3-pointers.

When you disaggregate the skew to each side by team, only three teams (Kings, Suns, Rockets) shoot close towards the sideline on the right than they do on the left.

Pull to Side by Shot Location

Team	Left	Right	Higher Absolute Value?
New Orleans Pelicans	8.81 Feet	-7.60 Feet	Left
Memphis Grizzlies	8.65 Feet	-7.85 Feet	Left
Philadelphia 76ers	8.88 Feet	-7.97 Feet	Left
Toronto Raptors	10.75 Feet	-8.08 Feet	Left
Minnesota Timberwolves	9.11 Feet	-8.14 Feet	Left
Oklahoma City Thunder	9.4 Feet	-8.16 Feet	Left
Chicago Bulls	9.11 Feet	-8.21 Feet	Left
Charlotte Hornets	9.26 Feet	-8.26 Feet	Left
Indiana Pacers	9.96 Feet	-8.27 Feet	Left
Boston Celtics	9.58 Feet	-8.33 Feet	Left
Brooklyn Nets	9.80 Feet	-8.36 Feet	Left
Sacramento Kings	8.32 Feet	-8.45 Feet	Right
Orlando Magic	8.65 Feet	-8.56 Feet	Left
Utah Jazz	9.41 Feet	-8.62 Feet	Left
Denver Nuggets	10.19 Feet	-8.71 Feet	Left
Dallas Mavericks	10.5 Feet	-8.71 Feet	Left
San Antonio Spurs	9.33 Feet	-8.72 Feet	Left
Washington Wizards	9.85 Feet	-8.92 Feet	Left
Atlanta Hawks	9.67 Feet	-9.1 Feet	Left
Milwaukee Bucks	10.41 Feet	-9.14 Feet	Left
Golden State Warriors	9.45 Feet	-9.15 Feet	Left
Los Angeles Lakers	9.38 Feet	-9.17 Feet	Left
Detroit Pistons	10.21 Feet	-9.6 Feet	Left
New York Knicks	10.69 Feet	-9.62 Feet	Left
Portland Trail Blazers	10.82 Feet	-9.64 Feet	Left
Miami Heat	10.94 Feet	-9.75 Feet	Left
Los Angeles Clippers	11.02 Feet	-9.8 Feet	Left
Cleveland Cavaliers	10.52 Feet	-9.85 Feet	Left
Phoenix Suns	9.65 Feet	-9.95 Feet	Right
Houston Rockets	9.96 Feet	-10.93 Feet	Right
New Orleans Pelicans	8.81 Feet	-7.6 Feet	Left