Hi, my name is Tom Haberstroh. I write over at Hoopdata.com about the NBA and occasionally perform statistical magic over at ESPN Insider. I have two middle names and enjoy watching Serge Ibaka play basketball. Chris Paul, Randolph Childress and Muggsy Bogues went to my alma mater and my favorite Crayola color is jungle green.
The topic of interest in my first piece here at Hardwood Paroxysm centers around team shot location. At Hoopdata, we track how teams shoot from five different areas of the floor: at the rim (layups, dunks, and tip-ins), less than ten feet, 10-15 feet, 16-23 feet, and beyond the three-point line. There you will discover, among other things, that the Chicago Bulls take an outrageous number of long twos and the Washington Wizards’ defensive unit practically ushers the ball through the basket on shots at the rim. Today, the statistic I am particularly interested in is shot location field goal percentage. More specifically, if a team is horrible at shooting around the basket, how much worse does it get when they face a team that protects the rim?
Take, for example, Monday night’s matchup between the Milwaukee Bucks and Orlando Magic. The Bucks are just about the worst team in the NBA when it comes to converting shots at the rim as their 56.0 FG% from there ranks 29th in the league. Dwight Howard and the Magic have the very best opponent at rim percentage (55.1 FG%). So, what happened? The Bucks missed 11 of their 20 shots at the rim while getting swatted eight times on the evening. And for the just the third time all year, Brandon Jennings didn’t take a layup all game. I wondered if this was a typical performance for a poor-rim offensive squad taking on a stellar rim-defense and whether this opposite holds true when the tables are turned.
To shed more light on my curiosity, I ranked each team of 2009-10 by their field goal percentage from each area and separated the league into thirds depending on rank in the category. Teams ranked 1-10 get tossed in the Good bin, 11-20 into Average, and 21-30 into Poor. You may have seen this filing method before over at 82games.com. So for example, the Chicago Bulls offense ranks 30th at the rim (Poor), 7th from less than 10 feet (Good), 5th from 10-15 feet (Good), 28th from 16-23 feet (Poor) and 14th from 3-point (Average). I then gathered every game (over 1,400 matchups in the sample) and calculated the field goal percentage in each shot location area. So, on average, what happens to a poor at rim defense when it faces a good at rim offense? Let’s take a look.

I’ll walk you through this. Defenses are separated by columns and the offenses are separated by rows. At the end of each column and row, you’ll find the average for that group. Ignoring the intersections for the moment, you see that the collective Good defensive group allows a .578 field goal percentage on shots at the rim and good offensive teams average .635. Now when they meet (say, when the Cavaliers, a Good at rim offense, faces the Celtics, a Good at rim defense), the Good offense shoots 61.3 percent from the area, on average. With me? I’ll take that as a yes.
As expected, teams perform better if their opponent defends worse in that area. The empirical evidence confirms our intuition. The Bucks-Magic matchup represents an extreme case on both ends, so the Bucks’ 45.0 FG% makes sense. On the other end of the spectrum, a good offense will dominates the poor defense, converting almost 2-out-of-every-3 shots at the basket. Interestingly, a poor defense will make a poor offense look average by comparison and a good offense will make an average defense look poor. Let’s take a look at shots inside 10 feet (not at the rim).
We see much of the same trends here in this one. It really hurts to be a poor in this area offensively going up against a good defense. Despite the near proximity to the basket, poor teams shoot 36.6 percent against good squads or roughly the same as the typical squad shoots from downtown. This zone gets about a third less shot traffic compared to the at rim zone, so the results will be more varied in one-game snap shots. How about the 10-15 feet area?
It doesn’t really pay all that much to be a good offensive team going against a good defensive team from the mid-range; the good and average offenses are nearly identical on average (.379 vs. .380). That’s the first time we’ve seen such a case. The typical team only gets about 7 shots per game from this area, so the numbers here will tend to exhibit more statistical noise. Nonetheless, if you’re facing a good defense in the mid-range, don’t expect your shots to drop no matter how well you normally shoot from there. Let’s take a look at what we see from the least efficient area of the five: the long two.

Long twos are much more stable than the rest of the fields we’ve looked at. The spread between PoorO-GoodD and GoodO-PoorD is only 68 percentage points whereas in the previous ranges the spreads were 111 at the rim, 139 from short, and132 from mid. But this follows the bigger picture. A good long two shooting team isn’t a whole lot better than a bad one. However, if you can’t normally knock down long jumpers inside the three point line (attn: Bulls), don’t get too excited when you face a bad defensive team on the perimeter. You’re still probably going to miss more than 60% of your shots from there.
Interestingly enough, a good defensive squad in this area has the opposite effect compared to the mid-range. Compare the good defense columns. Field goal percentage against good defenses actually increases from .366 to .380 as you migrate further away from the mid-range to long-range twos. Either a good mid-range D is especially suffocating or a good long-range D doesn’t amount to much in the end. A third explanation could be that the low sample size of mid-range shots on a game-by-game level produces some whacky results. And finally, moving onto the three point line.

For the purpose of staying consistent, I’ve presented the three-point numbers in field goal percentage as opposed to effective field goal percentage. Just keep in mind that even though the most advantageous situation yields only a 37.9 FG%, the added bonus of 1 point makes a world of difference. And much like shots from 16-23 feet, the spread between the best and worst intersection is only 73 points. Take a look at what happens when a good three-point shooting team goes from an average opposing defense to a poor one. The percentage actually decreases on average from .386 to .379. Good shooters from a particular area tend to improve across the board, however, from beyond the arc there doesn’t seem to be a discernible advantage. I’d only be speculating as to why this might be the case, if there is in fact a real effect here, but it could be that the difficulty of three-point shooting caps the shooter’s ceiling. The best shooting teams from long distance can only shoot so well since the threeball rarely goes in to begin with.
Like most studies, there’s plenty of room for more digging and statistical analysis. The logical next step would be to gather the variability, or standard deviations, of the presented figures. That way, we can see the overlap and strengthen our expectations. In this piece, I analyzed the league on a macro level but I could take this in other directions as well. How does each team perform against the various defenses? Moreover, do good shooting teams take more shots in areas where they have the upper hand? I’ll have to save those questions for another time. But for now, it does appear that teams experience greater success if the defense is weak in a particular zone. So keep these numbers in mind as you prepare for your team’s next game.
Stay tuned for more shot location analysis in the future editions of NBA HD.
If you can’t knock down long jumpers inside the three point line (attn: Bulls), don’t get too excited when you face a bad defensive team on the perimeter.