Does Guard Defense Matter?

[jonathanlambert33]

It has been remarked a couple of times this off season that the Celtics are going into the season with an upside down roster, their guards cant shoot and their bigs cant play defense. Certainly with Rajon Rondo, Phil Pressey and Marcus Smart on the roster, all with shaky three point shots, there is some truth to that. The Celtics front court also scored relatively poorly looking at the ability to protect the rim, using the new SportVu data.

But before we get too far into the specifics of the Celtics roster, as currently constructed, I want to question the idea that it would inherently be bad if a team did have an upside down roster.

James Brocato, over at his website Shut Up and Jam, did an interesting study that calls that idea into question. He looked at long term stabilized adjusted plus minus data, known as RAPM, comparing players by position on offense and defense. There are issues with RAPM to be sure, but in the realm of orthogonal data on basketball defense, the one eyed man is king. In any case, in the study, Brocato found that, yes, centers tended to score higher on defense on average than guards, and guards on average, scored better on offense.

So, centers are more important to defense, right?

Well, you may have noticed I used scare quotes there, because thats not whole story. Its true that the data supports the idea that a team benefits defensively having a center on the court. But the interesting thing Brocato found, was that the range of values between the top centers and bottom centers on defense was largely the same as the range between the top point guards and bottom point guards on defense.

Heres Brocatos image from his study:

http://nyloncalculus.com/2014/08/13/celtics-upside-roster-point-guard-defense/

 

[bosoxlover12]

I feel the title is misleading

Last line from the article

"But, what this data does indicate, I think, is that the difference between guards defense matters, perhaps more than we often give credit."

 

[jonathanlambert33]

This article speaks to exactly why I am so excited about what the Pelicans can become. The article basically suggests that replacing a average defender at the point guard position with a top 5% PG has as much of an impact on a teams defense as replacing a average defensive center with a top 5% one.

So what happens when the Pelicans replace below average defenders in Brian Roberts and Greg Stiemsma with top tier defenders at their positions in Jrue Holiday and Omer Asik?