There’s a problem with trying to take a statistical look at basketball: it’s hard to identify useful stats for individual defense. This problem has been discussed plenty, often concluding with the idea that it’s just really difficult to separate out a player’s individual contributions from the team concept. We may know that Andre Iguodala or Tony Allen are great defenders, but it’s hard to tell how great, or what about them makes their game so effective unless hours of tape are watched.
With the advent of new and different ways to break down the game, from Synergy Sports’ simple breakdowns of each play to the SportVu cameras which are compiling raw data on player and ball movement there is currently an influx of potentially useful data. This data is being handled in some interesting ways, as Zach Lowe detailed in this excellent piece about the Toronto Raptors. Still, the most relevant and widely available defensive stats are things like plus-minus numbers.
With the new data flowing in and being bent in a variety of interesting directions to try to get a better grasp of defense statistically, here are a few metrics that I would love to see in the near future:
Lateral Movement Speed/Change of Direction Time
To start off it’s important to think about the fundamental concepts of good defense. Perhaps the most central tenet is to put yourself between your opponent and the basket. In order to make this happen players spend basically the entire possession sliding laterally to position themselves where they need to be, and changing direction within this slide to stick with their man.
Knowing who is the quickest, both in terms of moving in one direction and in changing directions, would make it much more clear who has the tools to play great D. A guy like Tyson Chandler for instance moves very well laterally for his size, and he has been able to harness that to become an elite defensive big. On the perimeter guys like Iguodala and LeBron James are able to quickly get into position and stick with ballhandlers to prevent penetration.
These metrics wouldn’t necessarily demonstrate on-court value, but they could be very useful in scouting prospects or generally determining the areas that a player needs to improve. If the tools are there they may need to watch more tape, if not, more time with a trainer could be in order to work on their quickness.
Shot Angle Variation
Bear with me on this one. When jump shooters take a shot in an empty gym, they will release the ball from a certain angle. When there is someone in their face, the angle will be higher so the ball will (hopefully) clear the defender’s hands. A metric that showed which defenders were able to force big changes in a shooter’s angle of release would be be informative in determining who is consistently getting in the face of jump shooters and making their lives tough. The guys who can make a shooter adjust to them are almost always going to force more misses.
There are blocks, there are steals, and then there’s everything else. A third type of play which helps out a defense are deflections, tips, or anything else that knocks the ball away, however briefly. Anytime the defense knocks the ball out of bounds, pokes the ball away from a driving ballhandler, or tips a pass they are hurting the offense. Not to get too philosophical here, but that’s what the defense is supposed to do. So what if the offense gets the ball back? They have lost valuable time from the possession and now have to reset or scramble to find a sub-optimal shot. I say someone should be getting credit for that.
The ball has kicked around the perimeter, found an open man on the weakside, and now he is squaring up his shot. Would he rather see Josh Smith or Eddy Curry bearing down on him? Ok, that one is obvious, but what about deciding between Dwyane Wade and Iguodala? The less time a spot up shooter has to let one fly the better off the defense will be. A defender who can react quickly and is athletic enough to close the gap before a shot is taken has a lot of value against modern offenses that seek open threes on the weak side, and knowing the actual time that the close-out takes would be very informative.
These stats are fairly straight forward, and I’d be willing to bet that one or all of them, in some form at least, are being looked at by teams to start identifying better ways to judge defensive performance. Now it’s time for everyone else to get a glimpse at an improved lens through which to view the less-sexy half of the game.