Synergy, Holy Grail of basketball information. To use it is to be addicted, to be addicted is to sometimes abuse it.
I’ve lately seen many a writer and reader cite Synergy’s individual defensive statistics as argument trump cards. Hey, this player has a stingy points per possession (PPP), contrary to your denigration of his defense. Hey, this player can’t be good at D with a total Synergy rating like that. Eat your hat, gargle it with thumb tacks, you’ve just been Synergized!
The fine people at Synergy kindly curate many defensive plays into component parts. Thanks to them, we now have information on outcomes of isolations, post-ups, spot-ups, etc. This data is certainly interesting and valuable, but it should be applied wisely and modestly.
On Hang Up and Listen, Kevin Arnovitz cited how writers used Synergy to a good end. The Warriors trumpeted free agent acquisition Kwame Brown by referencing his “post defense” as an asset. Writers took to Synergy and checked Kwame’s data from those situations. Brown simply did not grade out as Kendrick Perkins of Charlotte, the numbers showed him to be below average at guarding the low block. This was a wise application. Take a specific claim, fact check it via a specific measurement.
But people falter when looking for absolute measures of overall defensive prowess. Unlike offense, defense is about prevention, and prevention is so difficult to quantify. Offense is often created by one man, bursting through a defense en route to a tangible reward. This act is easily recorded and credited to the athlete.
Defense is about five people working as one collective organism. If an offense-minded knight (named say, Brandon) bursts through a castle wall and lances an enemy nobleman, we know that he earned his mutton leg for that evening. Now say Brandon rides up and perceives the defensive fortress as impregnable. He moves in circles until the 24 second hourglass is empty, prompting him to slink off into the woods. Who deserves the mutton? The menacing archers on the castle’s left side? The screaming spear wielders on the right? Don’t forget the catapulters in back, those guys are such divas. Everyone played a role, but the outcome rewards no one in particular.
Synergy’s defensive statistics are outcome based. If someone misses a shot while guarded by LeBron James in an isolation situation, Bron’s defensive PPP goes down (a good thing). If LeBron prevents his man from ever catching the ball, there is no credit to be had. For all we know, the latter happens more often than the former does.
Or take this example, from Devin Kharpertian’s great work on New Jersey’s defensive ineptitude:
Deron Williams runs at a covered Nene for some strange reason–let us hypothetically deem this action a poor decision, one that is not dictated by team strategy. This leaves his man (Andre Miller) wide open at the top of the key. If defense is “everybody on a string” this is the point at which that string breaks. As the compromised Nets rush to recover, Miller throws a pass to an open Gallinari, and the rooster drains it.
Is Deron statistically punished for his defensive sin? No, and this result is fairly endemic to bad defense. Your mistake gets your teammate scored on, often on the other side of the court.
How did I learn about the displacement of defensive punishment? From Synergy of course. Their great video clip work can be highly instructive in showing how bad defense in one area can lead to a score elsewhere. I do not blame Synergy for providing data that people are over-applying, it is fantastic to see the end-game of every single score. But those who now know more on behalf of Synergy stats should know that it’s a sliver of the knowable. Outcomes are an important part of a complex story, but they should not be mistaken for the story itself.