The Tale of the NBA’s Top Two Offenses: An “Advanced Statistics” Explanation

Credit: NBA.com

(note: all stats were as of Wednesday morning)

The Oklahoma City Thunder and New York Knicks are the league’s top two offenses this season by offensive efficiency, according to ESPN’s advanced stats page. Each average over 110 points per 100 possessions, which is really, really good. But aside from the color scheme on the jerseys, these teams have little in common on offense, and their divergent paths to offensive greatness show that a strong offense can be achieved in more than one way.

First, I should explain what goes into offense in general, because I feel the best way to explain their success is through so-called “advanced statistics,” which are only slightly more advanced than their counting counterparts. Dean Oliver’s discovery and subsequent explanation of the four factors changed NBA thinking much like the discovery of the overall static nature of BABIP and pitching-independent-of-fielding were in baseball, though the four factors approach hasn’t nearly been discussed as much. It breaks down offense (and defense, for that matter, but we’ll focus on the offensive component for this post on offense) into four main factors, as explained by basketball-reference.com here, along with the statistics used to define those measures:

• Shooting – via Effective Field Goal Percentage (eFG%)
• Turnovers – via Turnover Rate (TO%)
• Offensive Rebounding – via Offensive Rebounding Rate (ORR%)
• Free Throws – via free throws made per field goal attempt*

*I actually prefer to combine shooting and free throws into true shooting percentage, (TS%), which takes into consideration both free throws and field goals into one tidy percentage. The math here is a bit more difficult to understand, though, and a formula can be found here. So I’ll use TS% as the base, and break that down into the two parts. If you’d rather just use eFG% and FT/FTA, go ahead.

One idea behind the four factors is the idea of a possession. A basketball game consists of possessions for each team, where each team has the ball in its control. A possession can only end in 3 ways:

• a made shot
• a missed shot resulting in a defensive rebound, or
• a turnover.

Made shots add to a team’s scoring total, and since that’s the objective, scoring as often and efficiently as possible should be the team’s offensive goal. Offensive rebounds result in the continuation of a possession, and often result in high-percentage shots. And turnovers end possessions in the worst possible way – without a shot going up – and often result in easy opportunities for opponents. As mentioned above, offensive efficiency is based upon points per 100 possessions, so that’s where this all links in. Teams that run faster use more possessions, so measuring offense per 100 possessions makes it so that teams who run at a high pace don’t have inflated numbers.

All of the statistics used in the four factors are slightly more complicated, but not at all overly complicated, versions of regular stats such as field goal percentage, turnovers, and offensive rebounds. Effective field goal percentage, for instance, counts three point makes as 1.5 two point makes because a three pointer is worth 1.5 two pointers. Turnover rate is just the amount of team possessions that end with a turnover. Offensive rebounding rate is the percentage of missed shots the offense rebounds. Again, nothing too complicated.

But knowing the fundamentals of how an offense works (or doesn’t) really can make what the Thunder and Knicks are doing make sense.  I’ll break this down by factor, starting with true shooting.

Credit: Newson6.com

True Shooting Percentage

Oklahoma City – 1st

It doesn’t really take advanced statistics to explain why Oklahoma City is so good on offense. They currently sit 2nd in the league in basic FG% and 3FG% (behind Miami, and not New York, interestingly enough). They also have two of the most dynamic players in the league in Russell Westbrook and Kevin Durant, along with sharpshooting wingman Kevin Martin and the rapidly improving Serge Ibaka. But the real reason Oklahoma City leads the league in true shooting: free throws. They lead the league in free throw percentage by 4 percentage points, which is ridiculous. They then combine that with the second most attempts, which makes that ridiculousness even more devastating. Despite being second – barely – in three point shooting, they don’t take enough shots from there for their shooting to be lethal (and for good reason – it would hurt their percentages, and likely their offense). But it doesn’t matter, because they get to the line so darn often.

New York – 5th

New York, unlike Oklahoma City, takes a little more digging to figure out how great they are. They rank 11th in FG%, 3rd in 3FG%, and 19th in FT%. But this is where weights, and more advanced statistics, really tell the story. The Knicks take more threes than any team in the league, and it’s not really close. At 29.5 a game, they average 2.5 more attempts than the second best team (Houston). Their new offense, complete with shooters (including Ronnie Brewer’s surprisingly stellar imitation of one) surrounding Tyson Chandler and Carmelo Anthony, created this monster. They also convert the third highest percentage on threes, so they make the most of their three point shooting. The rest of their offense is *just* good enough to keep the true shooting percentage high.

Offensive Rebounding Rate

Oklahoma City – 16th

About offensive rebounding so far this season – a lot of good offensive teams aren’t really focused on grabbing offensive rebounds. Oklahoma City ranks right around average. Offensive rebounding seems to have been de-emphasized around the NBA, as teams often look to send everyone back to the defensive end of the floor instead of allowing an easier chance for scoring in transition. Maybe more relevant is that as many good offensive teams fall below the NBA median for offensive rebounding as fall above the line.

New York – 26th

New York’s rebounding issues have been overblown, mainly because they regularly have just one capable offensive rebounder on the court at a time (Tyson Chandler) or none (if Rasheed Wallace is playing, since he generally floats on the perimeter). Like Oklahoma City, they don’t emphasize rebounding here.

Turnover Rate

Oklahoma City – 30th

And this is Oklahoma City’s biggest weakness, continuing a trend. The Thunder ranked 29th in total turnovers last season (ahead of, coincidentally, New York) and, more importantly, 30th in turnover rate. The Thunder’s two primary ballhandlers, Westbrook and Durant, create a lot of offense but, in the process, create a lot of turnovers as well. Just as guilty is Kendrick Perkins, who really shouldn’t be playing anyway, but that’s another story for another time. The gist: while creating tons of high-percentage looks, the Thunder can also be sloppy with control of the basketball and end up with the worst offensive output more often than any other team in the NBA. As it turns out, it doesn’t hurt that much because, again, they create better shooting outcomes than any other team.

New York – 1st

And this is where the Knicks break the code. They currently are on pace to break the record for fewest turnovers per game by an NBA team, last year’s offensively anemic Sixers squad. They also have a better turnover rate than those Sixers. But they combine it with, well, good offense. It’s what takes them up to number 2 overall – they shoot a lot of high quality shots and never have the worst offensive outcome, a very potent formula.

I’m not the first to take notice of the Knicks penchant for not turning the ball over and for shooting threes. Jeff Fogle, at his blog Stat Intelligence, has tracked the Knicks turnover and three point numbers and noticed a startling trend (in a good way, for Knicks fans at least): the Knicks have actually converted more threes than they have committed turnovers. In his “KRIB Index” posts, Fogle has kept track of every team’s 3’s-minus-TO’s stats and noticed the Knicks are far and away the best in this category. Notably, no team has ever come close to having more threes than turnovers. If the Knicks keep up their current pace, they could be the first team to ever reach that holy grail.

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As you can see, there’s a lot of avenues to having a good offense, but most important is that a team shoots really well. Basketball really is a make or miss game. Both the Knicks and Thunder rank in the top five in shooting. But in the other important areas, the Thunder come back to the pack while the Knicks surge up the offensive charts.  The rebounding and ball-control can certainly help, especially if they’re done at an elite level. The Knicks are certainly proving that, so far.