When I previously wrote about perimeter defense, I discussed the necessity of investigating so-called “league average” perimeter defenders as a next step. My intent for this article was to pick a few “league average” perimeter defenders to provide video and statistical evidence for what makes them “league average.” That is not what I ended up doing. After starting with Derrick White and scouting his defense, I ended up putting his numbers next to every other perimeter defender’s in a spreadsheet. Staring at that spreadsheet after watching his tape pushed me in another direction. Today, I present to you Derrick White and the Curious Case of the League Average Perimeter Defender.
(Note: I’m going to refer to my previous defense an article a fair amount, but I’ll only link to it the one time. You should go read it first.)
Finding a Simple Way to Define “League Average”
You may have noticed that I’ve been using “league average” in quotation marks. My reasoning is that despite its wide usage, I have no idea what it means with regards to perimeter defense. Terms like “relative True Shooting Percentage” are nearly ubiquitous on #NBATwitter because shooting percentages can be compiled, calculated, and compared in a neat little spreadsheet. Perimeter defense is much different for two reasons: 1. There is no simple metric one can use to evaluate perimeter defense, and 2. We haven’t established a universal way for grading perimeter defense. Since we’re all relying on hearsay and heuristics to judge perimeter defense, it’s impossible to establish what “league average” is.
To start my search, I used Basketball Index’s D-LEBRON metric to find a few guards around 0 which would indicate a neutral impact over 100 possessions. I landed on Derrick White (+0.03 at the time of writing), Justin Holiday, and Derrick Rose, but like I said, I only ended up considering White.
Derrick White’s Defense
As I noted in my previous defense article, “The simplest conclusion here is that great perimeter defenders make significantly fewer ‘Detrimental’ plays and more ‘Great’ and ‘Outstanding’ plays than poor perimeter defenders.” Essentially, the likes of Trae and Lillard made about 3 times more detrimental errors than Simmons, Butler, and Thybulle while making less than half as many great and outstanding plays. Because of this, I figured that White would be right in the middle. I was incorrect.
Watching the Film
Standing 6’4″ with a 6’7.5″ wingspan, White isn’t a pterodactyl. Regardless, his ability to block shots both at the rim and on the perimeter stood out. This two-handed block at the rim caused me to audibly yelp.
That’s not normal. In his Greatest Peaks series, which we discussed on Sense and Scalability, Ben talks about Russell and Robinson blocking shots above the rim in less than a second. White’s athleticism and stature don’t allow that, so this sort of block is particularly absurd. Furthermore, he showcased his blocking prowess in many situations such as staying in front of his man while jumping backwards at the rim — a Draymond special.
Of the 117 players that Basketball Index categorize as a guard (plus Simmons), White is second in blocks/75 possessions behind Thybulle (foreshadowing: I have more ridiculous Thybulle stats coming). Just after this, I was already questioning White’s D-LEBRON.
Although he did have his share of steals, none stood out as being especially impactful like the Simmons pick-six I discuss in the other article. However, I found White to be adept at drawing charges which would make him even more astute at protecting the rim compared to other guards.
All told, I came away impressed with White’s defense. He even showcased some “good” defensive plays which I didn’t formally track.
White Compared to Other Defenders
It’s easy enough to cherry-pick plays to make a case, but when I tallied the plays, he was still between Butler and Lillard, right? Wrong.
Uh, yeah, Derrick White stacked up pretty equally with some of the best perimeter defenders that I could find. I thought that if his sample of great/outstanding plays would match the likes of Simmons then his detrimental plays would be closer to Lillard’s/Trae’s.
(Huge caveat alert: I scouted White primarily through stats.nba so that I could get more data faster. Because of this, I’m almost certain that I’m undercounting the number of detrimental plays that he made.)
At this point, I was stumped. How could a player with a near 0.00 D-LEBRON indicate similar levels of defensive impact to Simmons and Butler? This is when I consulted the spreadsheets.
Blog Boy Stuff and Steals
Using Basketball Index’s droves of data, I started searching for a new gauge for analyzing perimeter defense. I’ve said before that I think that point-of-attack defense is overrated when considering impact and that off-ball defense is far more valuable, so I decided to be a caveman about it: I jammed off-ball stats together. Since most “great,” “good,” and “outstanding” defensive plays equate to steals, blocks, and deflections, I added every guard’s steals, blocks, and deflections per 75 possessions to see if that pointed me in the right direction. Not only does that simple metric correlate favorably to Basketball Index’s “Passing Lane Defense” stat, but it led me to a few possible answers. (From here on out, I’ll call the metric “Good/Great Plays per 75 possessions.”
First, when you sort all 117 guards by the sum of those defensive plays, White’s 4.7 Good/Great Plays per 75 ends up 25th. However, something stands out about him: out of the top 67 guards in my metric, White is the only one who doesn’t average a full steal per 75 possessions.
I feel that I’ve implicitly rebelled against steals, but the truth is that they’re extremely valuable. In 2014, Benjamin Morris wrote the following:
Steals have considerable intrinsic value. Not only do they kill an opponent’s possession, but a team’s ensuing possession — the one that started with the steal — often leads to fast-break scoring opportunities.The Hidden Value of the NBA Steal, Benjamin Morris, 2014
If we think about it analytically, a team that turns the ball over effectively ends the possession with a true shooting percentage of 0%. Consider a top-tier point of attack defender. Even in the best case scenario that doesn’t end in a turnover, the offensive player’s shot still has a chance to go in. The same is true for a rock-solid paint protector. NBA players are good enough to make scoring chances out of anything, so a defensive play that completely nullifies any chance of scoring is invaluable.
Furthermore, some of those steals can turn into a transition basket which, in the case of a pick-six (a steal that leads to a 1-0 fast-break), is the most efficient shot in basketball. When looking at an impact metric like D-LEBRON, those sorts of swings matter.
Zero is Good
After looking at White’s 25th ranking in Good/Great Defensive Plays per 75, I decided to revisit his D-LEBRON of +0.03. When I sorted those 117 guards by D-LEBRON, I found that White ranked 30th – in the ballpark of my metric.
To me, this was the simplest and most powerful reframing of defensive impact for guards. I shouldn’t have been looking at 0.00 as the average, but my stupid human brain couldn’t conceive of a negative number as good. To illustrate my point, here is every guard’s D-LEBRON charted by range.
Exactly 72.4% of all guards have a D-LEBRON less than 0. In other words, by this metric, almost three-quarters of all NBA guards who have played at least 750 minutes are below a “neutral” impact defender. Three times more guards are worse than -2 than better than +2, and four times more are between -1 and -2 than between +2 and +1.
Since 0.00 isn’t an indicator of “league average,” I took the average of all of their D-LEBRON which came out to -0.5.
Now we’re onto something. Instead of comparing a player’s D-LEBRON impact to 0, compare it relative to -0.5 for a more accurate look at his impact. All of a sudden, White’s +0.03 becomes +0.53 relative to other guards which matches the above film and statistical analysis. It also makes truly great defenders look even more unimpeachable: Thybulle’s guard-leading +2.3 becomes +2.8. By my rough calculation, that means Thybulle’s per 100 impact contributes about 7 wins over the average guard on defense alone! (Note: since he only plays 20 minutes per game, his per game defensive impact is closer to 3 wins over the average guard).
Every time I try and tackle a question I have about defense, I find myself getting lost down multiple rabbit holes. Nevertheless, I feel that I’ve come away with some clear conclusions this time. First, steals are important, and steals that lead to 1-on-0 (a pick-six) or other easy transition hoops are invaluable. One can be a perfectly lockdown defender, but if he’s not creating turnovers, he’s capping his defensive ceiling.
Second, “neutral impact” and “league average” defenders are not equivalent especially for guards. To be a neutral impact defender, a player’s impact must be exactly 0, but league average defensive guards have a worse than 0 impact on defense. Because of this, many of us ascribe the term “impact defender” to way too many guards unless we are, at the same time, saying that relative to other guards. In that case, we should say “so-and-so is an above average defender relative to other guards” if they’re not truly an impact defender.
Finally, guards simply cannot be the most impactful defensive player on the court. Matisse Thybulle — who I believe is the most impactful perimeter defender in the NBA — would probably cause a +1.75 swing on defense if he played starters minutes. On the other hand, Rudy Gobert is probably closer to +3.25. Based on the data I’ve presented, I wouldn’t be surprised if fewer than eight guards are even at a +1. I can’t speak to other centers, but I can assure you that it’s higher than that.
A Note About D-LEBRON
If you read enough of my work, you might notice that I often cite LEBRON over other impact metrics. Personally, I feel that it best matches what I see watching basketball, so for no other reason beyond that, I decided to get cozy with it. Furthermore, I think it’s valuable to deeply understand a couple of impact metrics – including their deficiencies – so that you don’t blindly cite numbers. When D-LEBRON didn’t make sense for Derrick White, I thought it would be more valuable for my analysis to see why it didn’t match the film as opposed to seeking out another stat that reinforced my analysis.
Overall, D-LEBRON has Thybulle at the top, Simmons lurking near the top, and Lillard/Trae near the bottom. Some players stand out as oddities (Dort is currently below league average on defense), but instead of throwing the baby out with the bathwater, this should inspire you to investigate why there’s a discrepancy between it and your own (or others’) analysis.
Finally, LEBRON uses inputs that aren’t directly from the box score or other tracking data (mainly luck-adjusted on-off numbers). Because of this, it’s impossible to fully match its output just by looking at a player’s stats and watching his film.
Cody Houdek is a writer and podcaster for Premium Hoops where he co-hosts Sense and Scalability. He also assists with videos for the Thinking Basketball YouTube channel. You can find all of his work (articles, videos, and podcasts) here.