Heat

LeBron James Playing Only 'Good' with Heat

| by David Berri

The Miami Heat are not loved by many people outside of Miami. And when the “Superfriends” struggled to start the season, joy was heard throughout the land (outside of Miami).

Naysayers noted, though, that the Heat’s early struggles were somewhat due to luck. The team’s efficiency differential (offensive efficiency minus defensive efficiency) consistently ranked the Heat among the league’s best teams. So even though their won-loss record indicated the Heat were close to “average”, stats people tended to say “we still expect this team to be among the league’s best”. 

Well, after just 23 games – yes, life changes fast at the start of a season in the NBA – we see the following:

  • With a record of 15-8, the Heat are tied for 8th in the NBA in winning percentage (not the best record, but no longer “average”)
  • The Heat are only four games behind the Spurs (the team with the best record)
  • More importantly, the Heat’s efficiency differential of 9.298 ranks third in the league, behind only the Celtics (9.302) and the Spurs (9.57)
  • The mark of 9.30 bests the mark of the Orlando Magic in 2009-10, the team that led the NBA last season with a differential of 7.95

In sum, Miami is actually a very good team. But as illustrated with the following table, Miami is not quite as good as the performance of the Heat’s players from 2009-10 would suggest.

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This team’s Wins Produced (and efficiency differential) suggest that the Heat are on pace to win 64 games this year. But last year’s player performance suggest this  team should win 70 games this year. 

Looking at the numbers for the individual players we see that the players who have declined the most are none other than the two stars the Heat added this past summer. LeBron James and Chris Bosh are on pace to offer 16.9 fewer wins than the performance of these players in 2009-10 would indicate. 

For Chris Bosh, this result is not that surprising.  Prior to 2009-10, Bosh had never offered an ADJ P48 mark in excess of 0.500 (go HERE to see what ADJ P48 means). So his mark 0f 0.440 this year is not completely different from what we saw before last year.

What we see with respect to King James, though, is surprising. LeBron’s ADJ P48 mark of 0.463 is quite similar to what we saw before the 2006-07 season. However, relative to last year, LeBron has seen his per 48 minute productivity decline by 0.158. In other words, LeBron’s drop-off is equivalent to the Heat completely losing the services of an above average NBA player (average WP48 – or Wins Produced per 48 minutes – is 0.100).

Of course it is obvious why LeBron is offering less. This must be another classic example of diminishing returns. As a player’s teammates improve, we expect the player to offer less. LeBron now has better teammates, so now he must be offering a lower level of productivity. Right?

Well, that may not be the big story about LeBron. Although diminishing returns is something that data clearly says happens in the NBA (after all, there is only one ball), the fall of King James is mostly about something else. Consider the data reported in the following table. 

When we think of diminishing returns, we first think about shot attempts (where the effect is the largest). And we do see that LeBron – relative to last year – is attempting fewer field goals and free throws. King James is also grabbing fewer rebounds, but that is probably not diminishing returns. Relative to LeBron’s 2009-10 teammates in Cleveland, his new teammates have a lower defensive rebounding percentage. So although LeBron is grabbing fewer defensive rebounds (the study reported in Stumbling on Wins suggests we don’t see diminishing returns with respect to offensive rebounds), LeBron’s drop-off with respect to defensive rebounds is probably not about diminishing returns.

The big story in LeBron’s decline is not diminishing returns (despite what we see with respect to shot attempts). The big story is his decline in shooting efficiency.  Last year LeBron had a 54.5% adjusted field goal percentage. This year his mark is only 49.6%. 

As noted a couple of days ago, changes in shooting efficiency has the largest impact on a player’s WP48. And LeBron appears to illustrate this point. 

Consider his performance last year. When we consider net possession (rebounds + steals – turnovers), LeBron wasn’t much different from an average small forward. So how did he produce more wins than any other player in the NBA? King James hit his shots at a very high rate (and it helped that he got to the free throw line and dished out a few assists). 

What’s interesting about LeBron’s shooting efficiency this year is that I think people would expect LeBron to be more proficient. After all, LeBron is now surrounded by better scorers. And I have heard that when a player is surrounded by more proficient scorers, the player’s shooting efficiency improves. 

Well, actually we don’t see that in the data. A player’s shooting efficiency does not appear to be related to the shooting efficiency of his teammates (a result reported in Stumbling on Wins). So it was not guaranteed that LeBron would shoot better with better teammates.

One might also expect that fewer shots taken would result in more efficient scoring (the classic usage story). But again – as we report in Stumbling on Wins – that effect appears to be exaggerated. We do find that increases in field goal attempts lead to lower levels of shooting efficiency, but the impact is very small (see the book for the exact numbers). And with respect to LeBron this year, this small effect is not appearing (the effect we estimate is what we see in general, not in every instance). 

Okay, we know LeBron has declined. We can see this isn’t really about diminishing returns. So what’s going on?

And this is where I run out of answers. Shooting efficiency is not as stable as other facets of player performance in the NBA (although it is still more stable than quite a bit of what we see in football). So maybe this is just a random fluctation. Or maybe there is a better explanation (and I sense people will offer some stories in the comment section).

Regardless of why LeBron is offering lower levels of shooting efficiency, we do know…

  • LeBron is still the most productive player on the Heat.
  • The Heat – even with LeBron offering less – are still one of the best teams in the NBA.
  • There is a good chance that the Heat — even if LeBron doesn’t return to form — are going to disappoint all the “haters” (can I note that I “hate” the “haters” label – even if I just used it?)

And if LeBron starts hitting his shots, there is an excellent chance the Heat will claim the top spot in the NBA (after all, they are almost there in terms of efficiency differential).

- DJ