EUROLEAGUE DEFENSIVE EFFICIENCY

Welcome back to Hack a Stat! The defense is today more than ever a tough task for all basketball teams. The current offensive tendencies (and some rules) make the defensive phase complex to be constantly brought on the court, especially if you do not have skilled players in this phase.
However, this does not mean that high-level defenses cannot be admired every year. But what does it mean to have a high-level defense? With the help of Instat, let’s see how Euroleague teams increase their defensive efficiency.

Italian version: https://lalentebasket.wordpress.com/2020/09/19/corner-stats-lefficienza-difensiva-episodio-1/

INTRODUCTION

Usually to identify the best defenses of a championship we look at the Defensive Rating and some other advanced statistics such as the Defensive Rebound Percentage.

The eye test, however, is essential to understand how a team obtains that Defensive Rating: this statistic summarizes in a single value all the efforts and tactical measures performed in the defensive phase. Obviously, equal Def Rtg values can be obtained in different ways. Each team uses their players in the best possible way to stop the opponent’s attack as many times as possible; I think the simplest example is the center’s movements in pick and roll situations. If you have a dynamic center, you tend to perform a show; if instead, you have a more statist center, drop is the smarter option. These two options will therefore be contemplated in the Defensive Rating, but it will be impossible to understand how much they affect the value of the statistic without the eye test.

PLAY TYPES

Thanks to InStat, however, it is possible to analyze numbers commonly not available to analytically understand which are the most important defensive aspects and how the teams behave. So let’s start by observing what are the most common play type situations in the Euroleague (the numbers refer to the past season):

Virtually half of the offensive solutions in the Euroleague take place following a pick and roll (PNR, where I have added together the situations concluded by the handler and the screener, both in roll and pop situations) and jump shots (this category includes catch and shoot, off-screen and hand-off; almost all are taken from behind the 3-point arc). The other half of the situations are concluded in different ways, with no particular percentage differences.
I don’t think there are big surprises in front of this chart: it is well known that PNR and jump shots are now the most used conclusions in modern basketball. However, being able to quantify their use helps to understand how much the teams exploit these two play types.

Let’s now observe the efficiency of the play types: the most useful value to understand that is the PPP (points per possession): thanks to this value you can understand the average efficiency of the League.

Some tips on the values shown: cuts and putbacks are situations in which players usually find themselves near the rim; they are situations where it is relatively easier to score. The most profitable play type, however, is the transition: honestly, I would have expected a slightly higher value, but anyway it is easy to understand why teams try to go in fastbreak as many times as possible: it allows them to play in numerical superiority.

HOW TO DEFEND THE MOST USED

Therefore, if we don’t consider transition, putbacks, and cuts, the PNR and the jump shots are the most profitable situations in half-court attack situations. The jump shots, influenced by 3-point shots, even reach values similar to those of the transition.
A defensive phase to define itself as a good level one must mainly limit three game situations: transition, pick and roll and jump shots (cuts and putbacks are off-ball situations that are born from passes or missed shots of other play type situations).

So let’s cross the PPP allowed by each team in the three play types identified as the most dangerous with the Defensive Rating.

EUROLEAGUE DEFENSIVE EFFICIENCY – TRANSITION

In this first chart, we can see the correlation between Defensive Rating and PPP allowed in transition situations. The chart trend is not so strong but we can see some interesting things anyway. In fact, except for Efes and Barca, all the best defenses of the Euroleague have a PPP allowed below the League average. It is also true, however, that there are teams like Khimki or Milan: they grant PPPs below the league average but have defensive ratings that are not exactly good. This heterogeneous arrangement is because a good defense is not a single-task job; teams have to be good in more game aspects to build a solid defense. This fact will become clear by observing the following charts.

EUROLEAGUE DEFENSIVE EFFICIENCY – PICK AND ROLL

In this second chart, I crossed the Defensive Rating with the PPP allowed in pick and roll situations. In this case, the trend line is even less sloped, meaning an even lighter correlation between the two crossed data. Once again, however, we can see how all the teams with excellent Defensive Ratings have PPPs close to or below the League average.

EUROLEAGUE DEFENSIVE EFFICIENCY – JUMP SHOTS

Lastly, I crossed the Defensive Rating with the PPP allowed to jump shots. Aside from Milan, the trend is very strong this time.

CONTESTING SHOTS

It is therefore interesting to deepen the discussion on this last chart before moving on to conclusions. From the disposition of the teams, it seems evident that a good defense depends on the efficiency with which the jump shots are contested. Analyzing the data relating to contested shots, I noticed that both the number and the quality of contested shots influence this defensive aspect.

To consider these two aspects together, I have summed up the percentage of contested 3-point shots out of the total number of jump shots and the opponent’s percentage of the contested triples into a single value, which we can define as Contested Rating. It is a percentile value that takes into account both the number and the quality of contested shots with different weights.

In this last chart, I crossed the Contested Rating with the PPP allowed in catch and shoot, off-screen, and hand-off situations. As you can see, the correlation between these two data is obviously very strong.

Now the question is: how can a shot be contested efficiently? Stevens’ Boston Celtics set the stage for it. By taking some risk (for example committing shooting fouls), the defender contests the shot with both arms raised, also performing a jump to reduce the distance from him to the shooter. Clearly having high backcourt players or dynamic big men helps a lot this technique: the more space they occupy, the more the shooter’s visibility is reduced.

This particular technique is now used by all professional teams. The quality (firstly) and the frequency (secondary) with which it is used are fundamental to effectively contest the opponent’s shots.
Teams like Barca, Real, Milan effectively and consistently contest the opponents’ conclusions from the arc.

CONCLUSION

In light of all these data, we can understand how a good defense cannot be considered as such if it shines only in a defensive aspect. Milan is the perfect example: an excellent team in contesting opponent’s jump shots, but on average when it comes defending a PNR. The best defenses since last season have been those of Maccabi, Baskonia, CSKA, Barcelona, and Real. In fact, all these teams fall into the best quadrant in pick and roll and jump shots charts, the two play types that we have identified as the most effective and used in modern basketball.