Ben Simmons as Defensive Unicorn

After a masterful performance against the Lakers, characterized by aggression, quality finishing, and all around effort, let's dig a little deeper into Ben Simmons’ game. The goal here is to use some non-traditional stats (things not found on NBA.com or Basketball Reference) to discuss his defense, because I found some pretty interesting things while digging around last night.

Full disclosure, most of the stats/metrics/numbers I reference will be coming from either things I created, or helped to create, and can be found here.

How Does Ben Defensively Impact the Opposing Offense?

One of my main basketball related interests is understanding and quantifying how players and teams on defense impact the shot profiles of opposing offenses. It’s tricky because so much of the defensive data that would be ideal for this is not available to the public. However, I think what comes next is pretty informative nonetheless.

On the high level, impacting the FG% of a specific offensive player is difficult regardless of how hard a contest is or is not. What’s better is to force that player to take a shot with a low expected efficiency. Following that train of thought, I developed a new advanced stat called Regularized Adjusted Deterrence, or RAD. There are two variations, RAD (vanilla version) and Q-RAD (slightly more involved).

Technical Note #1: RAD is essentially a cousin of RAPM and is generally calculated using the same ridge regression methodology.

What RAD does is provide a single value for how a player impacts the shot distribution of the opposing offense, with no regard to if the shots go in or not. Again, this is exclusive a field goal attempt based stat. Q-RAD is the specific variant we will be using here, which rewards defenders for giving up generally low efficiency shots from long midrange and punishes them for giving up generally high efficiency shots at the rim and from corner three. All other shots are neutral. Unlike other advanced stats, a negative value is “good”, and implies that the player in question reduces quality attempts from offenses. For example, one Joel Embiid leads the league in Q-RAD both this year (-7.99) and over a five year sample (-6.63).

If you want a more detailed explanation with charts, hit this link

Technical Note #2: RAD/Q-RAD are on a per-FGA basis and are not adjusted for pace

So for Ben specifically, this year has been his best so far in terms of Q-RAD, with a value of -1.35, which is about the 75th percentile or so, especially since it leans to post players on defense.

Let’s look at two charts that help explain this further.

In Figure 1, we look at lineups with Simmons on the court compared to the NBA Average. Areas in red are where shots are more likely to come against Simmons lineups than average, and blue the opposite. Something to keep in mind is that these contour plots looks cool, but are actually smoothed twice, so don’t over analyze these on the minute level. Broadly, there are more shots against Simmons lineups around the long midrange straight away and fewer wing/corner shots. This is tricky though since he literally can be covering the opponent’s center (where he is overmatched) or a perimeter (where he dominates), so it’s not surprising that there might a slight increase in shots at the rim with him on the court. Interesting, but just a descriptive tool (seriously don’t use this as “proof” of anything).

In Figure 2, we get a little more applied. The goal is to have opponents take more low efficiency shots or fewer high efficiency shots, and areas in purple show where Simmons lineups do that. Orange areas are the opposite. So his lineups produce approximately -2 points per 100 shots in the light purple areas. Of note, the -4 to +4 scale on the axis is the Joel Embiid (good) to Frank Kaminsky (bad) scale. Keep in mind that both of these charts are lineup related, so Ben plays with Embiid quite a bit, and also with no other bigs quite a bit.

Is Ben Really a 1-5 Defender?

Yes. Yes he is. We know this because of work that Krishna Narsu did based off of the idea of Patrick Miller. You can read the original article here if you’re so inclined. Krishna’s updated defensively versatility data can be found at this link, in the Versatility tab.

The basic idea of defensive versatility is the range of positions that a player guards, and the number of possessions that they guard against each position. While we know that traditional positions are kind of blurred these days, over the course of a season, the data is still highly informative.

The below table looks at the top-10 in defensive versatility for the current season, with the percentage of possessions guarding each position and their single year D-PIPM (ideally that would be multi year D-PIPM, but I wanted to restrict to same time scale). PEM, or position estimated matchup is the quantitative estimate of his defensive position. For example, a PG is 1.0 and a C is 5.0, if a player split their possessions 50/50 between those two positions they’d be a 3.0.

Note Simmons’ % vs. PG and % vs. C, that’s indication of real 1-5 guarding. You’ll note that James Harden is highly versatile according to this. Much of that is the Rockets potentially hiding him on various opposition players, as well as being a competent low post defender.

Figure 3 shows Simmons versatility over time against the rest of the league. His versatility is not a new development.

What Makes Him Unique?

We’ve established that Simmons can actually guard 1-5, although we have seen that true 5’s can give him some trouble (much like all of the above except Draymond). Now for the cool part. Krishna (who you should follow on Twitter), was able to then use the matchup data to determine how often a defender covers the #1 or #2 offensive options on the other team.

Table 2 below breaks that information out by the top-11 (wanted to include Jrue) in the percent of the possessions that a defender covers the offense’s primary option.

Figure 4 breaks out Simmons guarding by Option 1 and Option 2 by his position (PG).

Therefore, Simmons covers the offense’s primary option on approximately 26% of the possessions and the secondary option on approximately 16% of the possessions. Now, if you see the TWPU column, that’s where we go next. This refers to Two Way Primary Usage and is a joint venture (more like 90/10) between Krishna and myself. TWPU measures a player being the #1 option on offense and covering the #1 option for the opponent’s offense. Higher values correspond to more of the two way usage and lower values less. We know that Ben is not often the primary option on offense due to Joel and Tobias, so his is strongly weighted towards his defense, whereas someone like Dorian Finney-Smith is never the primary option for Dallas, so his TWPU is zero. TWPU can gauge the theoretical two way game load for a player, but is not yet quality adjusted.

Figure 5 shows Simmons (look for the X) in terms of O-PIPM and D-PIPM and TWPU.

So What?

• Ben Simmons is highly effective team and individual defender
• He actually can and does guard 1-5 and is one of the league’s top-10 most versatile defenders
• He guards the opposition’s #1 option approximately 26% of possessions, again in the top-10 for covering the primary option
• In combination, Simmons carries a high two way usage responsibility that is unique for players of his versatility

You can explore the data further and make all the above charts on your own at this link.

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