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Research - Defense based on shot location
David Locke - February 5th, 2012
Tags: Locked on Jazz
PREMISE OF RESEARCH
The main focus of my NBA research this season is how much of defense is simply forcing the opponent to shot from the correct location.
|
POINT PER POSSESSION |
||
|
LOCATION |
EFG% |
Pts per |
|
At Rim |
63 |
1.26 |
|
3-9 feet |
37.3 |
0.746 |
|
10-16 feet |
37.9 |
0.758 |
|
17-23 feet |
37.7 |
0.754 |
|
3 pointer |
51.7 |
1.034 |
|
FT% |
74.3 |
1.486 |
The premise is that if you can keep teams away from the rim and off the three point line you will be a good defensive team. The website hoopdata.com keeps a stat called XeFG. This is the expected effective field goal percentage of a team based on where they take their shots. Expected field goal percentage weighs a three point shot an extra *.5 since it is worth 50% more.
Twelve of the 30 teams in the league last year allowed an effective shooting % that was almost exactly what would have been expected simply by where the shots were taken. 20 of the 30 teams were within 2% of what was expected, 5 were considerably better and 5 were considerably worse.
Last year, the 4 best defensive teams in the NBA were Chicago, Boston, Orlando, Milwaukee and Miami. Orlando did the best job of any team at forcing teams to take the “correct or least efficient” shot. Boston and Milwaukee were 11th and 13th and Chicago was 16th with Miami 18th.
This shows that the best teams defensively are able to contest shots better than the other teams in the NBA. It also tells us most teams are not in that group. Chicago, Boston and Miami were remarkable shot contesters last year, whereas Cleveland, Detroit, Sacramento and Phoenix were very poor defending the shot.
JAZZ THIS SEASON
This season the Jazz are doing a better job than in year’s past at forcing the correct shot. This is largely because they are not following as much. For just the shots the Jazz are at 21st in the NBA at expected field goal % defense. In other words if every one shot average against every team the Jazz would come out 21st. Utah is actually doing a better job defending the shot than expected. They are allowing EFG% of 48.7% and based on where shots are being taken they should be allowing 49.7%.
I will continue to work on this throughout the season