Why don't advanced stats like Bradley's defense?

[PhoSita]

"Avery Bradley is one of the best perimeter defenders in the NBA."

That sentiment is one I've heard a lot over the years, but it's been repeated especially frequently recently with some excellent showings by Avery against the likes of Steph Curry and the Blazers' backcourt.

NBA players and NBA observers alike seem to agree that Bradley's tenacious defense is something else.



So why don't the stats support his status as one of the best defenders in the league?

He has a negative Defensive Boxscore Plus Minus.  His DRPM is negative also, and ranked quite low leaguewide.  He has 2.6 Defensive Win Shares on the season, which is fine, but not close to top 20.  His defensive rating is 106, which is not horrible, but not particularly great either.  His steal percentage of 2.2 is fine but far from exceptional.


What gives?

[JBcat]

I'm just taking a wild guess, but maybe when he is guarding bigger 2 guards verses opposing point guards his defense takes a hit.  I would be curious to know if the advanced stats can break it down by what position he is guarding, or even height of opposing player.

[jpotter33]

Now, I could be off-base with this, especially because I'm not really all that competent when it comes to advanced stats, but I think it has to do mainly with a distinction between two types of great defenders.

There are two types of great defensive players: stoppers and defensive quarterbacks.

Smart, KG, Draymond Green - these are all examples of defensive quarterbacks. They're great individual defenders, but they also make their team better defensively simply by being on the court because they're great team defenders as well as individual defenders, which is why their advanced stats are generally very positive of them defensively.

People like Bradley, and to a lesser extent Tony Allen and Jae Crowder, are stoppers. They're phenomenal individual player/ball stoppers, and they can exceedingly limit their individual player that they're guarding. However, a lot of times this comes at the expense of some team defense, or at least they're so focused on limiting their individual guy that their team defense suffers.

I think this observation works well with Bradley, because you always see him in this type of defensive role. However, there are a lot of times that Bradley and Crowder get a little lost with their help/team defense; whereas, you hardly ever see that out of the defensive quarterbacks like Smart, Green, KG, etc. They're always in the right place at the right time.

Sound plausible?

[chilidawg]

Good question, I've wondered the same thing.

As far as the individual vs. Team defense point, that makes some sense, but Crowder's drpm is very good, so maybe he does both well.  I'm leaning towards the "he's great against the curry/lillard types, but not so good against the bigger shooting guards" theory.  Don't know how to test it though.

[Boris Badenov]

"Avery Bradley is one of the best perimeter defenders in the NBA."

That sentiment is one I've heard a lot over the years, but it's been repeated especially frequently recently with some excellent showings by Avery against the likes of Steph Curry and the Blazers' backcourt.

NBA players and NBA observers alike seem to agree that Bradley's tenacious defense is something else.



So why don't the stats support his status as one of the best defenders in the league?

He has a negative Defensive Boxscore Plus Minus.  His DRPM is negative also, and ranked quite low leaguewide.  He has 2.6 Defensive Win Shares on the season, which is fine, but not close to top 20.  His defensive rating is 106, which is not horrible, but not particularly great either.  His steal percentage of 2.2 is fine but far from exceptional.


What gives?

I think that when the other players at the same position are also good, BPM and RPM are limited. They attempt to control for how the other players do, but if they are all good defenders, the data won't reveal exactly who is having the biggest impact relative to a replacement-level defender.

In this case you're looking at Smart and Turner, who are good defenders.

You'll see that Amir looks the best on these metrics, because he's implicitly being compared to Lee and Zeller.

My impression anyway.

[Androslav]

I think the answer is even more simplistic. Defensive stats are not as accurate and developed as the offensive ones. Bradley is a fantastic on ball defender, I have seen it, i dont need any stats to explain me that.
On the other hand, some advanced stats favor Pau Gasol, (sorry Pau, love your game) but it is pretty evident to me that he is poor on that end, at this stage of his career. I dont care about his 10 rebounds, good block totals, I wouldnt inlude him in the lineup to save the team from elimination.

[PhoSita]

Sound plausible?

It does, except that it doesn't account for why the defensive stats I mentioned earlier look much better for Jae Crowder and TA.

[kozlodoev]

He has a negative Defensive Boxscore Plus Minus.  His DRPM is negative also, and ranked quite low leaguewide.  He has 2.6 Defensive Win Shares on the season, which is fine, but not close to top 20.  His defensive rating is 106, which is not horrible, but not particularly great either.  His steal percentage of 2.2 is fine but far from exceptional.

Part of it is that these metrics are awful measures of defensive ability. Another part is that his defense is somewhat overrated.

[PhoSita]

He has a negative Defensive Boxscore Plus Minus.  His DRPM is negative also, and ranked quite low leaguewide.  He has 2.6 Defensive Win Shares on the season, which is fine, but not close to top 20.  His defensive rating is 106, which is not horrible, but not particularly great either.  His steal percentage of 2.2 is fine but far from exceptional.

Part of it is that these metric are an awful measure of defensive ability. Another part is that his defense is somewhat overrated.

Yeah, I'm inclined to agree on both counts.

I think Bradley is a good defender, but he gets extra love from opposing players who see (or experience) his persistent on-ball defense, and outside observers who appreciate the same.  Bradley's energy and persistence on the ball has always stood out.

My hunch is that maybe it doesn't always translate to a huge effect on the team's overall effectiveness defensively, though there are instances where it's clear that it does.

At the same time, I think the defensive stats are probably a good distance behind the offensive stats in terms of their efficacy.  Evaluating the defense of individual players requires measurements beyond those that are found in a basic box score.

[Chris22]

Bigger guards like OJ Mayo eat Bradley alive.

[mctyson]

He has a negative Defensive Boxscore Plus Minus.  His DRPM is negative also, and ranked quite low leaguewide.  He has 2.6 Defensive Win Shares on the season, which is fine, but not close to top 20.  His defensive rating is 106, which is not horrible, but not particularly great either.  His steal percentage of 2.2 is fine but far from exceptional.

Part of it is that these metrics are awful measures of defensive ability. Another part is that his defense is somewhat overrated.

You are right about #1 but the debate comes from both Lillard and McCollum stating that they believe he is the best.  And they would know much better than anyone on this blog.

[Rondo9]

I think Bradley plays alot with the bench which impacts his defensive stats.

[Smart457]

Bradley would be better if he had some back line support.

[kozlodoev]

He has a negative Defensive Boxscore Plus Minus.  His DRPM is negative also, and ranked quite low leaguewide.  He has 2.6 Defensive Win Shares on the season, which is fine, but not close to top 20.  His defensive rating is 106, which is not horrible, but not particularly great either.  His steal percentage of 2.2 is fine but far from exceptional.

Part of it is that these metrics are awful measures of defensive ability. Another part is that his defense is somewhat overrated.

You are right about #1 but the debate comes from both Lillard and McCollum stating that they believe he is the best.  And they would know much better than anyone on this blog.

The fact that Lillard and McCollum doesn't like having someone in their face when they dribble the ball doesn't necessarily make them an overall impact defender.

[Boris Badenov]

Sound plausible?

It does, except that it doesn't account for why the defensive stats I mentioned earlier look much better for Jae Crowder and TA.

I think it fits with mine though. Crowder's backup is who - Jerebko?

Also note that DBPM seems heavily skewed toward big guys - like, insanely so.

http://www.basketball-reference.com/leaders/dbpm_top_10.html

And we have two guys in the top 20 - Amir and Sully. KO's is quite good too.

It seems possible to me that DBPM somehow assigns good perimeter defense to the big guys playing with those defenders. Like, perhaps a primary effect of good perimeter defense is that teams take more difficult interior shots?

I'd have to dig into the mechanics of it though to say for sure.