# Nylon Calculus: Charting player passing lanes

There is this guy at the gym named Dave. He’s got above-average athleticism, sure; but only in that All-County, Honorable Mention sorta way. He can’t dunk. He’s not super fast. He’s more or less a regular guy. Except for one thing: he has this annoying knack for ALWAYS standing in the passing lane. Or, to be specific, he has a knack for always standing in MY passing lane.

Sailing a skip pass across the court to an open 3-point shooter? Nope — Dave was waiting there the whole time. Kicking it out to the top of the key from underneath the basket. Unh-uh — Dave was ready for that one too. Starting the possession with a lazy toss to the wing? Crap — Dave stepped into the passing lane and now he’s streaking the other way for a layup. Freaking Dave.

You probably know a Dave too. There’s a Dave or two in every run. And there are Daves in the NBA, of course. Andre Iguodala is a Dave, for example. Robert Covington, Thad Young, Ricky Rubio – they’re all Daves. They are those guys who just seem to know where the ball is going before it gets there.

But could I become a Dave? Could you? Could your local NBA player — with enough film study and personal training — become a Dave? I think so, yes!

By studying the tendencies of his opponent, a player can identify which passing lanes his matchup uses most often and which ones he neglects. And — in the same way that the red and blue hexagons of a shot chart can show the defender where to snug up on his cover and where to slack off — an assist chart could help a defender anticipate his opponent’s passes. Collectively, teams could adjust their defensive schemes to pull help defenders away from the blind spots that an opposing passer tends to overlook and reposition their players in a way that is most obstructive to the opponent’s favorite passing lanes.

That’s the idea anyways. The problem is that — using publicly-available data — there’s no real easy way to chart passing lanes. My fellow Nylon Nerds Krishna Narsu and Positive Residual have made the best of the available play-by-play data, by collating and charting the location of assisted field goals. However, the NBA does not provide the location from which the assist was thrown nor, for that matter, do they provide the location in which the assist was caught (the latter can sometimes be more than a few feet from the subsequent shot location).

So, in lieu of getting access to tracking data that would unlock a more sophisticated and automated solution; I just went ahead and watched a ton of clips that ended with an assist (thank you, 3ball.io/plays) and charted all the passes, one at a time. Using this brute-force approach, I was able to log a sample of 165 assists for each of four MVP candidates: Giannis Antetokounmpo, James Harden, Stephen Curry, and Nikola Jokic. These guys are all offensive focal points for their respective teams (team leaders in touches per game, for example); but they operate in very distinct ways from each other. Because they have different individual skill sets and play for teams with different offensive schemes, their assist charts are very different, too; making them fun to compare and contrast.

In the charts, each white line represents one assist from the 2018-19 season. The lines show the path of each pass from its point of origin (the vanishing tail) to the point where the scorer made the catch (the bright dots). The shot locations are not charted, specifically; although, in most cases, the catch and the subsequent shot occur in close proximity to each other.

The Photo-Hunt stars among you may be able to scan from panel to panel and spot the discrepancies. You should, at least, get a sense for the typical distance and direction of the passes used by each player and which locations on the court he passed to and from most frequently. You might also spot a few blank spaces.

But, honestly, it’s pretty challenging to digest all that information at once. I think it’s probably more useful to examine these assist charts a little bit at a time, for example, breaking them down by catch location. Let’s start by looking at all the passes these guys made into the painted area.

Focusing on the passes that were caught in the paint helps to highlight some of the different ways these offensive engines make their teams go.

The new-look Bucks offense is predicated on opening up space for Antetokounmpo to attack the rim. And, with all of his teammates clearing out beyond the 3-point line this season, he hasn’t had a lot of chances to throw an assist to anybody standing near the basket. Among the 165 assists I charted for Antetokounmpo, just 26 (16 percent) were caught in the paint.

On the other end of the spectrum, 79 of the 165 Harden assists that I logged (48 percent) were caught in the paint. The Rockets run a lot of pick-and-roll actions that send Harden rushing toward the basket with an option to dish to a rolling big man. These plays result in a lot of lobs and other assists near the hoop.

To be thorough, we can compare my sample of assists (165 each) with the full season of data for these players. According to PBPstats.com, 32 percent of Antetokounmpo’s assists and 56 percent of Harden’s were converted at the rim (remember, my charts are showing CATCH locations whereas PBPstats — and most other data — track SHOT locations). Among the top-50 assist leaders, those rim-assist rates represent the 4th and 94th percentiles, the extreme possibilities for primary ball handlers. For their parts, Curry and Jokic split the difference between Antetokounmpo and Harden for both paint and rim passes.

When we look at all the assists that were caught in the right corner, we see the panels once again differ by line density. Per PBPstats.com 19 percent of Antetokounmpo’s assists were corner 3s (98th percentile of top-50 assist leaders) compared to 16 percent for Harden (84th percentile), 10 percent for Curry (49th percentile), and just 7 percent for Jokic (10th percentile).

Aside from noting the differences in corner-3 assist frequency, it’s interesting to see from which spot on the floor each of these primary creators passes to the right corner. Antetokounmpo and Harden have a pretty similar pattern of kick-out passes, with the main distinction being that Harden tends to get closer to the basket before whipping his one-handed hook passes to the opposite corner. But look at Curry’s corner-3 assist pattern — it looks totally different than the others. He rarely passes to the right corner after driving into the lane, nearly all of his lines trace the paths of swing passes made from the right wing.

Here’s an interesting contrast: among the 165 assists I tracked, Harden threw 26 (16 percent) to the right corner and just 8 (5 percent) to the left one. By comparison, the other three stars demonstrated much more balanced corner-3 passing. Antetokounmpo, for example, had 22 assists to the right corner and 24 to the left.

Now, shifting our attention to above-the-break 3s, we once again see traces of Antetokounmpo’s kick-out output. Fully 82 of his 165 charted assists (50 percent) were caught above the break and, per PBPstats.com, 39 percent of his assists this season have been converted from that zone (98th percentile of top-50 assist leaders).

Keep an eye on the direction of the passes here. Harden’s lines are mostly pointing downward at 45-degree angles along the 3-point line, indicating that a lot of his assists in this zone are swing passes. Curry’s chart looks similar to Harden’s but it has more horizontal lines, which illustrate his flair for cross-court skip passing. In contrast, most of the Jokic lines are pointing up, showing his ability to pass out of the post as well as his effective use of dribble handoffs.

Having looked at all the passes that ended up inside the paint or outside the 3-point line, now we’re left with everything in between. Per PBPstats.com only 1 percent of Harden’s assists have led to long 2-pointers, less than any other top-50 assist leader. In contrast, 11 percent of Curry’s assists generated long mid-range shots (80th percentile). You can see the difference in their assist charts where Curry had 35 assists (21 percent of his 165 assists) that were caught between the paint and the 3-point line, whereas Harden had only 8 (5 percent).

So that’s what it looks like to divvy up these assist charts by catch location. Alternatively, we can also look at them by the location of the passer. For example, here are all the assists these players made from the backcourt. Curry (with 26) and Harden (with 29) are both expert long-outlet passers, frequently spotting open teammates while dribbling up the court. Despite tossing a few unforgettable long bombs this year, Jokic only had 8 assists from the backcourt. Likewise, even though he brings the ball up a lot, Antetokounmpo had just 4 assists that crossed midcourt in midair.

To emphasize the differences in passing ranges between the four players we can rearrange the assist charts to center each line around the passer’s location. In this way, we can directly compare the distance and direction covered by each pass.

In these charts, the intersection of the two red lines shows the point of origin for all the assists. Each concentric gray circle marks a ten-foot increment, so that any lines which stretch beyond the outer ring represent passes that traveled 30 feet or more. These charts also show the direction of each pass — towards the basket (down), away from the basket (up), or side to side.

We can convert this from a chart of individual passes to one with zones sorted by distance (0 to 10 feet, 10 to 20 feet, 20 to 30 feet, and 30+ feet) and direction (toward/away from the basket and left/right) —  to create an assist heat map. The red zones show the distance and direction in which each player is most likely to assist. The black zones show where he is least likely to assist, his blind spots.

One interesting observation from these blind-spot charts is that Harden passes to his right a lot. Of his 165 assists charted, more than half (55 percent) were thrown forward and to the right, whereas only a quarter (25 percent) went toward the basket from right to left.

Harden’s propensity for passing to the right is a function of his left-handedness. He likes one-handed passes — hooks, slings, lobs — that tend to work better when he throws them from left to right. Harden’s signature assist is that one-handed scoop alley-oop he throws to Clint Capela, which he can pretty much do from any distance.

Taking the time to chart 600 assists one play at a time might sound like a drag to you; but, with high-quality passers like these, it can actually be pretty fun! Jokic, in particular, is joy. It’s his funky release points, his unexpected pass angles, and his total lack of explosion —  or, sometimes, even a lack of any movement at all — that make his passing so refreshing to watch. I got a special kick out of seeing all of his passes from the top of the key.

Here’s something kinda fluky about Curry’s assist chart. Among the 165 assists I tracked, 8 of them were on inbounds passes. That’s a lot. And it makes me wonder if teams could be doing more to prepare for the Warriors set plays; although, in reality, it probably has more to do with Golden State’s great shooting than any tactical advantage they have had on inbounding sets.

Finally, here’s one scouting tidbit that came out of these assist charts which might be legitimately useful. Antetokounmpo has set up a huge number of 3-pointers this season with dribble handoffs. That’s not necessarily unique. I mean, the Nuggets actually used the DHO even more than the Bucks in the plays that I watched. But what makes Antetokounmpo’s handoffs noteworthy is that he has a DHO-sweet spot. He’s created about a dozen different 3-point DHO’s this season from one particular location on the court — the foul-line extended on the left side. So, next time you’re guarding Tony Snell or Kris Middleton in the left corner and you notice Antetokounmpo dribbling towards you — brace for impact!

OK then — now we have the blueprint for shutting down Antetokounmpo, Harden, Curry, and Jokic, right? Ha, not really — obviously, an assist chart is far from a cheat code.

Still, I wouldn’t want Dave reading mine.