By Stephen Shea (@SteveShea33)
February 2, 2017
We recently released a metric for individual perimeter defense (or at least our first attempt at one with modern data). The purpose of this post is to examine how this metric, Perimeter Defense Rating (PDR), behaves at the team level.
We ran the formula for each team as if the team were a player. Memphis rated the highest, with Golden State, Toronto and Milwaukee not far behind. Detroit, Orlando and Denver took the bottom three spots.
Of course, the perimeter is only one component of team defense. We wanted to see how team PDR worked in conjunction with interior defense. We considered a team a “+” perimeter defensive team if their team PDR was not negative. 13 of the 30 teams qualified. We considered a team a “+” interior defensive team if they held opponents to less than 60% shooting at the rim. 11 of the 30 teams qualified. Portland and Utah held opponents to the lowest FG% at the rim (just under 56%).
Interestingly, among the top 8 teams in opponents’ FG% at the rim, 7 were a negative in team PDR. This strongly suggests that it’s hard to play great defense at both the rim and the perimeter. Intuitively, that makes sense. If you press up on the perimeter to try and get turnovers or to prevent quality 3-point attempts, you are leaving space in the middle of the court and are vulnerable to drives and cuts to the paint.
In total, 4 teams qualified as both a + perimeter and a + interior defensive team. Those were Golden State, San Antonio, Memphis and Atlanta. All 4 are in the top 5 in defensive rating.
The following chart shows the average DRtg among teams categorized by whether or not they met the + defensive qualifications.
It’s no surprise that teams that can be plus defenders on both the interior and perimeter have the best overall defense. Preliminary findings suggest that excelling in both is an exceptionally challenging task.