NBA HD: Blocks Not Just A Defensive Stat Anymore

Today’s post explores  a fairly new basketball statistic that hasn’t been analyzed in the public forum: percent blocked (%Blkd).

Well, maybe that isn’t totally accurate.  Matt Moore flirted with the shot blocked stat earlier this year in this very space but his love affair phased out as the season went on.  It’s a shame really because %Blkd awareness has plummeted ever since.  What is %Blkd? It’s the percentage of a player’s shots that get blocked.  Simple enough.  Although, it’s not to be confused by Basketball-Reference’s handy BLK% which calculates the flipside for the defender.

%Blkd is so simple that it feels like we should have had this information all along.   We make a big deal out of blocks for defenders but we ignore the other side of the ball.  Luckily, Hoopdata began publishing this data this season for the swat hungry masses.

Looking at the leaderboard of those who get denied a lot and those who leave the court unscathed, you find some interesting results.  No one’s safe from the swat.  Some of the tallest players to grace the court get blocked and the some of the shortest ones never do.  Seven-footer Brendan Haywood gets blocked more often than his 5-11 Carolina counterpart Ty Lawson.  Sure, Brendan Haywood lives in block territory and Ty Lawson only takes about half as of his shots at the basket (which is astoundingly high for a point guard) but evidently it takes more than height to be the last one to touch the ball as it approaches the rim.  In the former Knickerbocker department, Nate Robinson, who stands 5-9,  gets blocked less often than Darko Milicic who stands 84 inches tall.  Guess who takes more shots at the basket? That’s right: Nate. #wordaapp.

So anyway, who finds himself on the Most Blocked List? Let’s take a look at the ranking if we trim those who don’t play 20 minutes per game.

No surprise there with Chuck Hayes at the top. He’s undersized for a shooting guard but he’s employed at the 5.  But what about athletes like Tyson Chandler, J.J. Hickson and Gerald Wallace? Did you think their other-wordly hops would protect them? Not so actually.

And what about the Least Blocked List?

Notice some trends here? Bigs who lack an outside shot lead the blocked shot list and the guards who are allergic to the paint have gotten blocked fewer times than a highway patrol squad car.  Most blocks occur around the basket so if a player made it a priority to not get blocked, he could just live on the perimeter.

With that in mind, if the object is to learn something about the skill set of the players, these rankings probably aren’t all that informative.   We might as well look at their shot locations since there’s a very strong correlation between  the percentage of a player’s shots taken at the basket and how often they get blocked (r = .708, in fact).

What we want to find are the players who attack the rim cleanly without getting their shot swatted into the first row.  To do this, it’s worth looking at the relationship between percent blocked and how often they take shots at the basket. We measure the latter through at rim percentage.

In the chart below, we can glean more information about the player’s block evading skills if they display a separation from the pack.

At Rim Pct

There’s a lot to take in here, I know. Names, colors, lines. Oh my! Don’t worry, I’ll walk you through it.  (Click here for the standalone graph).  First, I elected to display the data points as player names instead of regular dots.  I mean, there are real people behind those dots so I just went ahead and identified them.   Secondly, the colors of those names correspond with their position. Consult the legend at the top left.  You’ll notice the orange centers cluster to the right. Lastly, the lines you see are trendlines for the positional distribution.  I wouldn’t put too much weight in the G and F trendlines since they only represent a few observations in the dataset but they’re there anyway.

Looking at the graph, we see that the Portland (and also injured) version of Marcus Camby has a much lower blocked percentage than we would expect given how much he works the basket.  Maybe he’s learned a thing or two from all the shot-blocking he does himself.  Or maybe it’s just a small sample of games (it is).  On the other end of the spectrum, Carl Landry strays from the pack, getting blocked on about 14% of his shots in Houston which is much higher than what we’d expect for someone with his taste for layups.  And the full season Landry (Carl Landry TOT), isn’t much better. You can see Steve Blake tucked in the bottom left hand corner.  He’s right on top of the trendline which tells us his tiny %Blkd isn’t really special.  Move along.

Speaking of which, why do we have the trendlines? For one, they provide a nice baseline so if the player finds himself above it, that tells us he gets blocked more than we would expect.  And vice versa below the line.  Secondly and most importantly, the regression equation associated with the trendline for each position enables us to derive an expected %Blkd with what we know about their propensity to take layups, dunks, and tip-ins.  For example, a 10 percent increase in At Rim Pct for centers increases %Blkd by 1.2 percent.  Furthermore, point guards suffer more compared to centers the more layups they take which seems logical given their stature.

So we want to find those who deviate from the expected line the most.  In other words, who gets blocked way more than they should given their appetite for layups?

Chuck Hayes no longer tops the list, all though he’s still a card-carrying member of this shameful group.  The new leader, 6 foot 7 Chris Douglas-Roberts gets blocked three times more than he should for a small forward taking 44 percent of his shots at the rim.  Gerald Wallace, for all his explosiveness, dunking chops, and athleticism, features an alarmingly high blocked percentage, moreso when he consider his position.  If all of Crash’s 101 blocked shots came at the basket, that would mean that one out of every five shots he takes at the rim get blocked.  If there’s a dent in his game, this is it.  And he’s not the only stuffed athlete on this list; Corey Maggette, Rudy Gay, and Caron Butler find themselves here as well.

Butler’s stint in Dallas has not been a slam dunk and maybe it’s because he hasn’t had enough of them.  He’s had his shot blocked a whopping 23 times in his time in Dallas, a high total considering he only takes a few shots at the basket per game.  He’s traditionally been blocked more than average but this is definitely something Mavericks fans should note as they march into the playoffs.

With the weak finishers taken care of, what about the undeniable attackers?

As remarkable as it is that Marcus Camby has only been blocked twice in Portland, the real leader on this list is Ben Wallace who should have given up about twice as many swatted shots as he has.  This is particularly interesting because Ben Wallace at 6-9 is woefully undersized for a center.  He’s not Kevin McHale underneath the basket but he certainly picks the right spots to get a clean look at the basket.

Notice that many of these players double as shot blockers on the defensive end.  Iguodala and especially Wade rank among the top shot-blocking guards.  On a per minute basis, Chris Andersen blocks more shots than any regular.  Dalembert and Camby are right up there.   Perhaps these players possess a shot blocking intuition and instantaneous jumping ability that helps not just on defense but on both ends of the floor.  Of course, not all shot-blockers avoid getting their own shots swatted (ahem, Brendan Haywood) but this is certainly an intriguing finding that I’m not sure I’ve seen before.

In the future, I’ll call up player height and And-1 percentages in effort to get closer to the heart of finishing ability. The findings here certainly warrant a deeper look to investigate further if shot-blocking ability translates to offense as well.