# A Review of Euroleague Basketball Clubs Perspective on Rotation

One of the greatest challenges for basketball coaches is to find the perfect balance between the lineups they deploy. The so – called “Rotation” is one of the most used terms in the sport. Especially the last couple of decades it has been a topic with a lot of discussion about. A big question is whether teams should rely more on their key players.

#### Abstract

In this research, the effect of role players on success of a team and more specifically in Euroleague Basketball is analyzed. Quite recently, more and more coaches set their rotation in such a way that even the 9th or 10th player in the hierarchy are considered quite important. In the first part, the author uses a series of indexes to find which team had the most balanced rotation during the last season. Subsequently, the correlation between this balance and final team position is examined. The overall aim is to determine if clubs that use more players and distribute minutes more equal, are those which finish in the top positions of final standings.

#### Introduction

Rotation was an unknown word for majority of European coaches till late 90’s. Teams were usually built around one or two players, who were their stars. Everything was planned to meet their playing style or attributes. However, this changed over the years. Nowadays, we have reached an era where reserve players play a more important role for their success. In the following paragraphs the researcher will examine how balanced was the rotation of the top European basketball clubs during last season, as well as its correlation with their performance.

#### Data Collection and Methodology

For the purposes of this research, data from all 16 teams of Euroleague Basketball during 2017 – 2018 regular season was collected. More specifically, total minutes and points scored. Team performance will be analyzed making comparisons between the starting lineup and the players coming off bench. This will be done using the Herfindahl Index.

Herfindahl Index (also known as Herfindahl Hirschman Index) is used widely in economics as a measure of market concentration. The closer a market is to a monopoly, the higher the market concentration. In basketball, it can be used to measure scoring balance and minutes distribution. The calculation formula is the following :

$HHI&space;=&space;Starting&space;Lineup&space;Share^2&space;+&space;Bench&space;Lineup&space;Share^2$

It ranges from 0.5 to 1 and the closer to 0.5 the value of the HHI, the more balanced the team is. For example, between two teams, the one that has greater scoring HHI has less scoring balance between starters and reserve players (meaning that one of those two categories contribute more towards scoring than the other one).

#### Evolution of Rotation in Basketball

Basketball in Europe has changed so much over the years that the average minutes per game of a player have seen a significant decrease. 30 or 40 years ago the majority of teams had 3 or 4 players averaging at least 30 (and sometimes 35) minutes per game. In addition, the match squad consisted of 10 or 12 players but in many cases no more than 8 or 9 them were used.

Extensive rotation has made its way into coaches’ philosophy, who see the importance of having a squad where even bench players can make a big difference. Thus being said, they have to decide whether they would prefer to be in charge of a team where its starters are amongst the best in the league but their role players of much lower ability, or one with greater balance between those two. In other words, should quantity be more important than quality or vice versa? Is it possible to find the perfect balance between those two?

Euroleague Basketball teams can be a great study case for this topic. It is a common assumption that weak sides depend more on their star players as they cannot afford having or attract many superstars. Likewise, strong clubs can probably rely on bigger number of players and even distribute playing time better amongst them and giving the chance to their stars to rest and the others to be active and in game fitness. Focusing on 2017 – 2018 season, it would be interesting to see therefore if teams which performed better were more balanced in terms of scoring and minutes distribution than the others.

#### Final – 4 teams

Having a look at Real Madrid’s squad, it is quite evident that its squad was probably the strongest in Euroleague Basketball. The Slovenian wonderkid Luka Doncic was the MVP of the league, while other members such as Randolph, Ayon and Fernandez could be key players for many teams. What makes this even more impressive is that Sergio Llull missed almost the entire season. Pablo Laso did a great job in terms of roles distribution. During regular season, only in 3 out of 30 games starting lineup played more than 60% of total game time.

On the other hand, Zelimir Obradovic preferred a different approach for Fenerbahce Ulker. He rarely used more than 10 or 11 players and the ratio between starting and reserve lineups quite often was around or exceeded 65 – 35%, especially during the first half of regular season. However, there is an explanation behind that as there are not many good domestic players available and therefore Turkish players were merely members of squad in order to meet with the restrictions set for Turkish League.

CSKA Moscow and Zalgiris Kaunas were very close to Real Madrid and Fenerbahce Ulker respectively. CSKA used less number of players per game in average, but the minutes distribution was slightly more balanced than Real Madrid. Zalgiris Kaunas lies between those two and Fenerbahce Ulker. It should be mentioned though that it had more close games than the other 3 teams, so coach Jasikevicius was forced to use his key players more often.

The previous outcomes are sum up in the following chart.

Chart by Visualizer

Another intriguing remark is that in the case of Real Madrid and CSKA Moscow, their minutes distribution was less balanced than their scoring distribution. In simple terms, their bench players were more efficient scorers than their colleagues of Fenerbahce Ulker or Zalgiris Kaunas.

#### Top – 8 Teams

Amongst the 4 teams that made the quarter finals but not the Final – 4, there is the following paradox : Panathinaikos Athens had the biggest number of players used per game (11.4) but Baskonia was the one with the most balanced minutes distribution. By taking a closer look though to league player stats, one can see that Chris Singleton and Nick Calathes were in Panathinaikos’ starting lineup in all games they were available and they averaged nearly 60 minutes accumulatively.

Khimki is the greatest example of 9 or 10 man rotation analyzed so far. The 5 members of starting lineup in each game, were on court in average approximately 62% of playing time. What is more, they scored 67.7% of Khimki’s total points. How weak was its bench is also evident by its scoring performance. Not only its scoring HHI was the highest as a result of the large proportion of points scored by the starting lineup, but additionally there is a big difference between this index and the minutes distribution HHI.

Panathinaikos’ bench players were quite efficient though in terms of scoring. They shared 43% of total minutes in average and scored 43.3% of total team points. In other words, in a 50 – 50% minutes distribution they would score the same points as the starting lineup. The same applies for Saski Baskonia.

The chart below illustrates those conclusions. Overall, those 4 teams were less balanced than Final – 4 teams and relied more on their key players.

Chart by Visualizer

#### Rest of Teams

The usual thought is that those teams get involved in more close games and have limited budget (or prefer to spend it to attract 2 – 3 very good players and a few with supplementary role). In that case, they do not have the same chances to rest their starters often during a game or trust more than 10 players.

7 out of 8 Euroleague Basketball teams which did not qualify to playoffs, had a minutes distribution HHI greater than . Their starting lineup was usually the one that had to do all the hard work. In fact, the relevant function is monotonically increasing starting from a value equal to and even reaching , in the case of Anadolu Efes. Even the average number of players used per game for those teams ranges from 9.8 (Anadolu Efes) to 11 (Unicaja Malaga and Crvena Zvezda Belgrade). To understand better the difference from the teams which finished above them, only 3 clubs used less than 10.9 players per game.

There is one big exception to this general rule though. Unicaja Malaga not only had the most balanced rotation amongst all 16 teams, but furthermore this one was close to perfect. In 13 out of 30 games, their bench players even spent more time on the floor than starters. Only 2 players (Nemanja Nedovic and James Augustine) averaged more than 23 minutes per game.

Chart by Visualizer

As it is also evident above, the scoring distribution HHI follows almost the same pattern as the minutes distribution one.

#### Correlation Between Team Performance and Roster Balance

In the final part of this research, the author will gather the previous outcomes to determine whether more balanced rotation leads to better team performance. To do this, the correlation between the previously used indexes and team final position will be examined using Pearson’s Correlation Coefficient.

Regarding the average number of players used per game, the R Value of the coefficient is equal to -0.45 . There is a negative correlation, which can be considered weak though; stronger sides usually use more players but this cannot be said with certainty.

The R value for the correlation between minutes distribution HHI and final position is equal to 0.53. This is a moderate positive correlation which means the less balanced the rotation of a team (higher HHI value), the worse the team performance.

The relevant value for points distribution HHI however is significantly lower, equal to 0.31 . Even though there is a positive correlation, this is not strong. More balanced scoring between starters and bench players does not necessarily happen only in teams which make the Final – 4 or playoffs. For example, Unicaja Malaga and Maccabi Tel Aviv were ranked 2nd and 3rd respectively in that list but finished 9th and 10th.

#### Results and Discussion

By having a look at the following table, reader can get a clear idea of all data and results earlier demonstrated.

TeamPlayers Used Per Game
Minute Share, Starters
Minute Share, Bench
Points Share, Starters
Points Share, Bench
CSKA Moscow10,8
0,5260,474
0,495
0,505
Fenerbahce Ulker10,40,5590,4410,57
0,43
Olympiacos Piraeus11
0,5680,4320,5780,422
Panathinaikos Athens11,4
0,5690,4310,5660,434
0,5270,4730,5020,498
Zalgiris Kaunas110,5530,4470,5890,411
Khimki Moscow Region10,60,6170,3830,6770,323
Unicaja Malaga11
0,520,480,5360,464
Maccabi Tel Aviv10,30,5560,4440,5480,452
0,5720,4280,5710,429
Brose Bamberg10,90,5650,4350,5540,446
FC Barcelona10,7
0,5570,4430,5720,428
0,5870,4130,5930,407
Armani Exchange Olimpia Milan10,6
0,5850,4150,5830,417

Amongst all 16 teams participating in the latest edition of Euroleague Basketball, Panathinaikos Athens averaged the biggest number of players used per game. However, Unicaja Malaga was the one that had what can be called as the most balanced rotation between starters and bench players. In addition, the most balanced performance in terms of scoring belongs to CSKA Moscow

Another remarkable point to make has to do with Anadolu Efes. They were the worst ranked team in all 4 categories : average number of players used, minutes distribution HHI, scoring distribution HHI and final position.

Last but not least, it was found that there is a correlation between team performance and minutes/scoring distribution. Nonetheless, this is not very strong to fully justify that.

#### Summary

To sum up, rotation in basketball nowadays usually seem to be a key factor for the success of a team. Good balance in playing time and roles distribution between starting and reserve lineup can lead to great team performance, and vice versa. As this research showed, Euroleague Basketball clubs which qualified to Final – 4 or the play – offs at least had a greater balance than the majority of those which finished below them.

#### Bibliography

Euroleague.net. (n.d.). Turkish Airlines EuroLeague – Welcome to EUROLEAGUE BASKETBALL. [online] Available at: https://goo.gl/sRYoHy [Accessed 2 Aug. 2018].

Investopedia. (n.d.). Herfindahl-Hirschman Index – HHI. [online] Available at: https://goo.gl/fPzL3q [Accessed 1 Aug. 2018].

Whitehead, T. (2018). Nylon Calculus: Steve Kerr coaches like a role player. [online] FanSided. Available at: https://goo.gl/6aL4j8 [Accessed 1 Aug. 2018].

### Konstantinos Kotzias

I believe that sports and data science interrelate perfectly and their combination gives us the chance to understand better the whole science behind a single game. Therefore, for me Statathlon is a unique project that enables me to use my passion for research and writing about an important aspect of my life.