Kirk Goldsberry and some other Harvard folks have written a new piece on Grantland about NBA defensive metrics. They will be presenting their work at Sloan, and are also publishing an academic paper on the subject. They are using the SportVU cameras to first understand defensive assignments (who is guarding who at any specific time), and come up with various metrics, including: "1. Defensive Shot Charts: Depictions of how a defender’s opponents shoot and score against him. 2. Counterpoints: Estimates of how many points an individual defender allows, per 100 possessions." 3. Contest Rate: what percent of shots do you contest when you're on the floor 4. Points Against 5. Attempts Against Goldsberry fans, fear not, there are plenty of hexagons in the article. Of course, the reality is always more complicated than these metrics (being only metrics), with the prevalence of help defenses. Just because the model thinks you are defending someone, and they make a field goal, does not make it your fault.