Harden Versus Elite Defenses

One of the stories right now is the supposed implosion of James Harden, the breakthrough shooting guard who's lauded for his scoring efficiency but receives heavy backlash from people who hate his flopping and deride his game, calling it bland and, since he has no midrage game, devoid of skill. Critics also imply he's somehow paying off the refs or the league has an interest in his success, like it would make sense to conspire in an effort that could get you fired for propping up the NBA markets of Oklahoma City and Houston. Now there's a widespread declaration that he shrinks in playoff games and against good defenses, coming of a disappointing finals from the 2012 season and the recency bias of some high turnover games against the Thunder. While the playoff woes deserve a little more time because you can't judge a player based on so few games, Harden just spent an entire season as the number one scoring offense and we should be able to tell if he indeed struggles against top defenses.

Methods to the madness

There actually isn't a single straightforward way to judge how well someone fared against a defense. Points doesn't tell you how many shots someone missed or turnovers created. Focusing on shooting efficiency doesn't account for more of an offensive burden: if you take more shots, your efficiency typically decreases. There are lots of single number metrics (too many, honestly), but not all have an only offense component and none are perfect.  The best approach is to analyze this from multiple angles and look for patters, as well as comparing Harden's output to that from the league's other top scorers.

But what myths are we looking to bust? Does Harden perform worse as the defense gets better? Generally, every player gets worse as the defense gets better, because it's better defense. I'll separate all the different hypotheses about the general myth of Harden shrinking versus top clubs.

1) Hypothesis: Harden's offense performs worse as opposing defenses defenses get better.

2) Hypothesis: Harden's offense performs worse than expected as opposing defenses get better. Expectation is based on the opposing team's allowed points per possessions.

3) Hypothesis: Harden's offense performs worse compared to other high scorers as opposing defenses get better.

The data

Using basketball-reference's team defensive ratings and their offensive efficiency rating for players, I've produced the graph below. Usage percentage is the percentage of team possessions a player uses based on field goals, free throws, and turnovers. I've coded usage with color so you can see if Harden is getting less attempts in games against elite defenses, and everything is on a per possession basis so there's no bias in pace or minutes played.

I don't see how there's any pattern between Harden's scoring and the opposing team's defensive rating, and unless you're John Nash you won't find one either. People may get distracted by the clump of low efficiency games versus the league's two best defenses, Memphis and Indiana, but he had another game versus Memphis with an offensive rating of 153 and above average usage -- and yes, Tony Allen and Marc Gasol played, and Memphis was blown out. Additionally, he had a string of good games versus the league's third best offense the Spurs. Using regression, you can test whether or not the defense is a significant predictor of various offensive stats. I've included a summary below, and the results are much like the scatterplot: there is no link. I've also used home/away games as a dummy variable, in case that was influencing the result. It's an interesting sidenote, but with Harden and the other top scorers their production does not appear to be significantly affected by away games.

	Offensive rating	Offensive game score	Points/minute	Usage %	Assist %
Coefficient	0.885	0.319	0.216	0.118	0.409
p-value	35%	28%	36%	50%	33%

*Offensive game score is the game score outlined here but without the defensive components

The most telling fact from the results is that none are statistically significant (near the 5% p-value threshold.) There's simply too much noise and variation. He doesn't appear to perform worse in a systemic way. The offensive rating coefficient is interesting. Since it's on the same scale as the defense (the dependent variable), a coefficient less than one means Harden is performing better than expected. (This can also be taken as an inelastic value.) The best way to understand the coefficients is to think of the league's best defense with a rating around 100 and one of the league's worst defenses with a rating around 110. With a ten unit decrease (going from a terrible defense to an elite one), Harden's points per 36 minutes only decreases by two points, his assist percentage by 4%, his offensive rating by 9, etc.

How does he compare versus the other top scorers? Using the same basic regression of offensive rating or usage % versus the opposing team's defensive rating (points allowed per 100 possessions), I created two tables for easy comparisons. Keep in mind the scale and units of the coefficients, and that negative means you're actually improving as the defenses get better. The p-value shows statistical significance (anything around 5% or lower.)

The results are surprising. In offensive rating, Harden performs better than anyone except for Carmelo Anthony. Harden maintains a healthy offensive rating as the defenses get better, and his usage is only slightly decreased. Keep in mind that his results aren't statistically significant, so you can't actually say he performs better or worse. However, the other scorers are more interesting. Durant's efficiency plummets (a coefficient of 2.8 is huge), while he increases his scoring load a far amount, but not enough to offset his efficiency. Both Kobe and James see their efficiency take a dive, and they don't see a significant ride in usage to counteract it.

Offensive rating versus opposing defensive rating

	James Harden	Carmelo Anthony	Kevin Durant	Kobe Bryant	LeBron James
Coefficient	0.885	0.282	2.82	1.74	2.18
p-value	35%	77%	0.029%	3.1%	0.31%

Usage rating versus opposing defensive rating

	James Harden	Carmelo Anthony	Kevin Durant	Kobe Bryant	LeBron James
Coefficient	0.118	-0.0731	-0.431	-0.176	-0.108
p-value	50%	77%	4.5%	47%	51%

Of course, team roles play an important part because elite defenses are better at certain techniques of flooding the strong side of the court or controlling the top scorer with a premier wing defender. But Harden has a tougher role than some of the other stars: he's the only focal point on offense and the only top creator. James has Wade, Durant had Westbrook, and at least Kobe had Howard, who demanded more defensive attention than anyone else on Houston's team.

Speaking of team effects, one might wonder if Houston performs worse against better defensive teams in the regular season. Well, this is pretty easy to test. Using b-ref's definition of offensive/defensive efficiency, I grabbed Houston's data from the regular season and calculated their offensive efficiency in each game to compare it to the defensive efficiency of their opponent, and used regression (again.) Basically, Houston has a coefficient of 1.08 for defense, which means they play slightly worse than expected versus better defenses, but it's so slight it may not be significant. So I then constructed an expected efficiency differential. This is just the difference between Houston's offensive efficiency for a game and the opposing team's defensive rating for the season, along with the effect of homecourt advantage. Just to be sure, I did this with an assumed homecourt advantage for Houston of 2.32 and league average of 3.23 from this study, and again with home and away as dummy variables so the model calculated its own homecourt advantage numbers.

Long story short, Houston's offense does not perform significantly worse than average. For the expected efficiency differential model with HCA built in, the coefficient for defensive efficiency was only 0.0108 -- translated, in going from an elite defense (rating of 100) to a crappy one (rating of 110) they'd be only 0.108 points per 100 possessions worse than expected. The variable wasn't significant -- or close to it. (As a fun statistical side note, the standard error was forty-six (!!) times larger than the coefficient, and the R^2 value was a minuscule 5.8*10^-5.)

Hypothesis 1: Does Harden's offense get worse as defenses get better?

There appears to be a slight relationship of team defense and his offense, but it's not statistically significant. Hypothesis 1 is actually rejected.

Hypothesis 2: Does Harden's offense perform worse than expected as defenses get better?

Since hypothesis 1 was rejected, this one also falls, and actually Harden was performing better than expected (due to his coefficient being less than one for offensive efficiency) by some metrics.

Hypothesis 3: Does Harden's offense perform worse compared to other top scorers as the defenses get better?

No, and actually he looks better in comparison. This one, however, will be the focus of future research (how top scorers fare against top defenses.)

Harden may depend on his foul drawing abilities for his scoring, but this is true of many elite wing scorers in the past from Jerry West to Jordan. Perhaps he's a playoff underperformer, but he hasn't played enough yet to brand him with such a slanderous accusation. Being called a playoff failure is a career killer, as David Robinson knows all too well. He doesn't have a midrange game, but he's one of the few players who can successfully shoot three-pointers at a healthy percentage off his dribble, and his team doesn't perform worse than expected as defenses get better. Being dependent on the two most valuable shots (three-pointers and at the rim attempts) in the game should in fact be considered a strength. The Beard has his detractors, but his game is holding up.

Edited: Added a section on how Houston performs as defenses get better.

Harden Exits Stage Right: Enter Kevin Martin and Lamb

While I was playing around with a model to predict wins for teams in the 2012-13 season, I heard the news of the Harden trade.

I was shocked.

He's a "mere" sixth man of the year, but he's a 23 year-old gifted scorer (and passer) who completed a season that by TS% and usage% (how efficient his scoring is and how often he shoots) has only been bested by Charles Barkley and approached by Nash, Kevin McHale, Amare Stoudemire, and Adrian Dantley. That's it. It was a historic shooting season, and at his age it's intriguing to wonder what will be. Obviously, without Westbrook and Durant the game will change for him, but given how well he plays as a ball-handler a bigger role will not be a negative: he'll play more minutes and put up more shots, averaging 20+ on stellar percentages. With the shooting guard position unbelievably weak (beyond Kobe and Wade the cupboard is bare), he has a chance to pick up all-star teams and other distinctions. He is by no means perfect, but with how his age aligns with the other Thunder big names -- Durant, Westbrook, and Ibaka are all within roughly a year of one another -- it pushes their core from very promising to unbelievable. Now that's gone.

Kevin Martin has an interesting story from the perspective of those who study NBA stats. From his box score stats, he appeared to be an underrated shooting guard star because of his elite TS%. (That sounds familiar, but Martin's was only in the 62% range.) He is, however, essentially a poor man's Adrian Dantley. This is not a compliment: Dantley was an amazingly efficient scorer, but he was known for not helping his team win by killing the offense through ball-stopping and not playing defense. Likewise, the evidence came in that despite Kevin Martin's shooting skills (and he's great at drawing fouls) he doesn't actually help a team all that much, mostly because of his defense, but even on offense he doesn't seem to add a lot of value. The funny thing is, he's not even a "star" on paper because his shooting is deceptively efficient: he'll shoot 8/19 from the floor, but he'll pick up 10 foul shots and hit 4 three's. In an earlier article, I discussed how there are microscopic (box score, numbers for single events) and macroscopic (how a team plays when a player is on or off the court) views of the NBA in terms of statistics. Kevin Martin viewed microscopically seems great, but from the big picture angle he's a detriment to his team and he's only getting older.

How will this affect Oklahoma City, owner of the youngest team in 35 years since the '77 Blazer, weighing their age by minutes played and by starting lineup? Since I was already working on my simple wins predicted model, I estimated playing time for the scenario keeping Harden and one with keeping Kevin Martin, and calculated some numbers. I predict the win percentage based on point differential, so it's best to compare the expected win percentage from last year in the table to this year's expected win percentages.

	2011-12	2012-13 with Harden	2012-13 without Harden
Wins	47	59.1	53.8
Win %	71.2 (69.8*)	72.1	65.6
Off. Eff.	5.2	5.0	3.3
Def. Eff.	1.4	2.5	1.7

*Expected win percentage from point differential and strength of schedule
-Efficiency scores are based on the league average (5 is significantly higher, while -1 would be below average)

The Thunder by my rough estimate will drop about 5.3 wins losing Harden, which is surprising considering most of their players are young and they should be improving. Their 2012 season was supported by an elite offense, and their moderate drop (due partly to a small decrease in minutes for Durant who shouldn't keep playing as much as he has) is recovered by better defense, which is what you'd expect from a young crew still learning how to compete. But losing Harden and replacing him with Kevin Martin's defense kills their offense and stunts their defense. 59 versus 54 wins may not seem like a terribly large gap, but when you're aiming for a title that's like plummeting an entire tier. What's worse is not next season but the ones after that -- instead of keeping a 23 year-old Harden they could either let Martin's contract expire or re-sign him or another cheap player, lowering their ceiling for years to come.

Of course, those are crude estimates, and I'm not stating they'll be accurate. The Thunder may not even keep Kevin Martin, instead dumping his expiring contract elsewhere and (hopefully) picking up a good player in the process. It's not a buyer's market for shooting guard, unfortunately, as Harden was the best piece remotely on the market now that Iguodala has switched teams. They could use the amnesty option on Perkins and pick up a quality big, but they'd still have a hole at the shooting guard position.

But there's still hope. The Thunder grabbed rookie Jeremy Lamb, an intriguing shooting guard with insanely long arms and an outside shot; with good luck he can turn into the kind of defensive ace with reliable three-point range so many great teams covet. There are also a couple picks thrown in, mostly notably a reverse-protected first round from Toronto, meaning OKC will net the pick if the Raptors miss the playoffs (an easy assumption). If Jonas Valaciunas and Kyle Lowry play well, however, the pick could end up in the 10-12 range. With fortune on their side, the Thunder will hope one of their rookies or draft picks will end up being as good as James Harden was.

The constellations have realigned in the west. Oklahoma City's dominant future has faded, though still potent through Durant and Westbrook; and Harden joins Lin and Asik on a pastiche of intriguing young players, as the Big Trade Morey was aiming for has landed. The Lakers and Spurs rejoice.