We Can’t Talk About NBA Defense. That’s a Problem.

There was an offhand remark in a recent Zach Lowe column on ESPN that pointed out Klay Thompson‘s positive attributes as a wing defender, and Thompson enjoys a reputation as one of the premier stoppers in the league whenever he’s got a man in front of him.

Anyone who watches Warriors games can see it.

But on the other hand, Thompson’s advanced defensive metrics range from “mediocre” to “utterly putrid, like among the worst in the league” when you look him up on Basketball Reference, his 112 Defensive Rating, minus-2.2 Defensive Box Plus-Minus, and that stat’s subsequent drag on his VORP (which at points during the season was “below G-League” level before Thompson’s three-pointer came back from the dead) suggest a guy who can’t guard a chair, never mind elite NBA players.

All of the above on a Warriors team that is middle of the pack defensively, so he’s having his stats neither artificially made to look better by great defensive teammates nor dragged into the sewer by playing for a terrible defensive team.

So what gives?

Well, for starters, while you can mix and match offensive statistics in myriad ways in order to produce both distilled-to-one-number stats like PER and much more granular locational shot breakdowns, the only three defensive counting stats we have are rebounds, steals, and blocks.

And sure, stuff like SportVU can tell you how a guy’s matchup shot during a man-to-man matchup, but how instructive is it if you have a guy you’re guarding who’s moving without the ball, losing you on screens and back cuts, and otherwise getting his points from means other than beating you one-on-one?

And what does “great on-ball defender” even mean against teams that never run isos?

What I’m saying is that Zach Lowe (and the Warriors fans who kill me on Twitter when I bring this subject up) can say that Klay Thompson is a great defender, and they can run a bunch of film, and Klay looks like First Team All-Defense.

Then I can turn around, point at Klay’s horrendous defensive advanced stats, cite Sheed’s Law, and say Klay isn’t worth a nickel on the trade market defensively compared to guys like Ben Simmons, Lonzo Ball, and Marcus Smart. (and yes, Lonzo’s got a fantastic statistical case for First Team All-Defense.)

And we can get in a slap fight over it on Twitter until the cows come home.

This needs to be a priority in the league office. Because the advanced defensive metrics that are out there and available to journalists and the public without needing to understand a lot of statistical esoterica (and perhaps more importantly, for those who do understand such things to be able to distill those brain-breakers into a form that casual fans can understand) simply don’t exist.

Of course, there are plenty of other ways we can talk about defensive impact.

To wit, there’s “just look what happens to them when he’s out.”

This is also known as the Gobert-Turner Principle.

We know Rudy Gobert and Myles Turner are great defenders because the Jazz and Pacers can’t stop anyone without Gobert and Turner, respectively, on the floor.

Of course, this also sails wide like a Carlton Banks halfcourt heave when put to the test of context.

Derrick Favors is nowhere near the equal of Gobert defensively, and neither is Domantas Sabonis anywhere near as good a defender as Turner. If Gobert got hurt and the Jazz had Turner as the backup, and if we didn’t know from having watched him in Indiana how good Turner is, we’d be tempted to say that Gobert can’t be that good because he’s easily replaced.

Likewise, if Sabonis were the equal of Turner as a defender, we wouldn’t say nice things about Myles defensively—as in Serious NBA People who are not Pacers fans agree he deserves consideration as Defensive Player of the Year—because he’d look replaceable. If anything, we’d be giving Quin Snyder and Nate McMillan, Gobert and Turner’s coaches, more credit than we give to the players themselves.

If a guy can’t shoot, it doesn’t matter who his coach is or who his teammates are. He’ll shoot shots in situations that other players all around the NBA do, from certain distances, on catch-and-shoot or off the bounce, driving the lane or hanging back for three, from the midrange or in positions that don’t make fans cringe…and it’s apples to apples to compare him to any other player in the league taking the same shot.

If a guy can’t play defense, it isn’t that cut and dried.

Bottom line, we can chop up offensive stats, serve them in every cuisine under the sun, and create rich narratives.

But defense? No matter how you argue it, someone’s going to think you’re dead wrong, and they’ll have a point.

This needs to get better. The NBA needs to commit to better defensive metrics and make them publicly available.