September 26, 2017

Analyzing Hertha Berlin’s Two Year Evolution

Hertha Berlin have qualified for the Europa League. The last time this happened was in 2008-09, so this is quite an achievement for the capital based cub. After all, they were relegated in 2009-10 and promoted the season after (2011-12) for a year (losing via the relegation playoff to Fortuna Düsseldorf). Since 2013-14, Hertha has held steady and now with former player Pal Dardai at the helm, can the club nicknamed ‘The Old Lady’ (like Italian giants Juventus Turin) destine themselves for greatness? In this piece, Alex Rathke examines Hertha’s last two campaigns and asks whether even bigger success for Hertha lies just around the corner.

Before I start, I want to get something off my chest. Over the past two years, I have found following Hertha quite agonizing and stressful at times. While Dardai has ensured two consecutive finishes in the top 8 these last two campaigns, I silently squirm when January comes around. Based on my observations and the way the table changes week-by-week, Hertha have a stronger Hinrunde than Rückrunde in general.

Season Position  Total Points Hinrunde Points Rückrunde Points
2016/17 6th 49 30 19
2015/16 7th 50 32 18
2014/15 15th 35 18 17
2013/14 11th 41 28 13

Since its Bundesliga return in 2014-15, Hertha has had this incredible ability to hit the ground running in the first part of the season, so it’s almost as if the winter break does more harm than good for them. It’s fairly obvious, but Dardai and his staff need to find a way to motivate/control the team’s energy, so that they can go maximize their points intake in the Rückrunde. It’s not just the first and second parts of the season that are causing issues. Their home and away form could also not be more opposite from each other.

This line graph charts Hertha’s seasonal progress from both 2015-16 and 2016-17.

Hertha’s Two Season Overview

Goals scored and conceded on a year-by-year basis don’t tell us much about a team. However, Expected Goals (xG) For and Against can though. For those of you not familiar with xG, you may want to read this article or Opta’s German version. In short, xG evaluates the quality of shots created by teams and states the expected goals we would have expected teams to score and concede (based on the quality of these chances). My own xG model takes three factors into account when computing xG:

  1. Distance from goal.
  2. Angle to the goal.
  3. Footed vs headed shots.

Next, here are Hertha’s xG numbers — both attacking (“For”) and defensive (“Against”) — from the last two seasons:

  • 2015-16: Attacking xG = 35.89 (1.05 per game); Defensive xG = 42.33 (1.25 per game)
  • 2016-17: Attacking xG = 34.02 (1.00 per game); Defensive xG = 45.27 (1.33 per game)

Based on my model, Hertha scored 7 more goals in 2015/16 and 9 more goals in 2016/17 than its xG would indicate. Defensively speaking, Hertha conceded the amount of goals we would have expected it to conceded based on the quality of shots faced.

Shots

Hertha Berlin was among the Bundesliga’s fewest shot takers in 2016-17.

Hertha are a side who don’t exactly take a lot of shots. To put that into perspective, only Darmstadt took less shots than them this season and they got relegated. That’s not to say that Hertha will get relegated next season, they’re just very laid back with their shot volume.

For the last two seasons, Hertha have only taken more than 10 shots per game in 36 of the 68 Bundesliga games (18 games both season). There’s been studies which have researched shot volume and its effects on teams winning or losing matches. Shooting more does not exactly mean you will win games, it just means you have more chances.

Nonetheless, under Dardai, the number of shots taken per game is up by (9.76 to 10.21) from last season. What does that mean? Essentially the difference of why Hertha scored more goals but slightly less xG is due to the quality of chances taken (fallen from 11% to 9%). In summary (on average), Hertha this year were taking more shots, but the quality of those shots was reduced quite substantially.

Can we look at specific areas of the pitch and examine where 1) this increase in shots per game and 2) this reduction in quality has come from? Yes, we can. The underlying principle of xG is that shots further out are of lower quality. I will use the 18-yard box image below to help breakdown and illustrate the point.

The danger zone in the middle allows for more goals on average.

The 2016-17 season saw Hertha take more centrally located shots than the season beforehand. To put that in perspective, in comparison to 2015-16, Hertha increased their shot numbers in the Danger Zone (DZ), while decreasing their shots in the wide areas of the box. This inherently increased the quality of shots taken by Hertha, however their increase in shots from outside the box counters this. The increase of nearly a shot per game from outside the box can explain the reduced quality of shots taken by Hertha.

Personnel

In terms of personnel, it is good to see Hertha’s two most attacking minded players Salomon Kalou and Vedad Ibisevic taking the most shots out of the team’s total. In 2015-16 they combined to take 35% of Hertha’s total shots while 2016-17 was lower at 32%. How or why was it lower? Was it due to less shots taken by Hertha? No, as we established that above. So what else could it be?

Taking a metric called “per 90” into account, we can baseline players’ metrics to the amount of time they spent on the pitch. This can be used for shots, passes, assists and so forth. I have decided to focus on shots alone as they are attacking players and that is what you want from them. The following table shows how Kalou and Ibisevic have both decreased their shot volumes from last year.

Player 2015-16 2016-17
Minutes / Shots Taken / Per 90 Minutes / Shots Taken / Per 90
Salomon Kalou 2535 / 56 / 1.99 1997 /38 / 1.71
Vedad Ibisevic 2097 / 61 / 2.62 2723 / 71 / 2.35

As we can see, the numbers are a bit different for both players. Kalou had more game time last season, whereas Ibisevic had more this season. As we would expect, the shot volumes differ to how much the players played, yet over the course of the time spent on the pitch, shot volumes were down for both across the board. Why would that be? Well for one, age. Both are not the youngest anymore (31 and 32). Colin Trainor from Statsbomb wrote a great piece on this. Before Dardai dipped his toe into the transfer market, the next two “listed” attackers in the team were Sami Allagui (31) who has since left (for St. Pauli) and Julian Schieber (28). Again, both are not the youngest either and have not exactly played a lot of football last term (170 and 423 minutes).

We looked at shot volumes, but how did they fared in xG. Penalties were removed from this sample.

Player Expected Goals (xG)  / Actual Goals
2015/16 2016/17
Salomon Kalou 7.19/12 3.42/6
Vedad Ibisevic 10.49/10 9.95/9

As with the shots taken, both players are scoring less xG than the season before. As well as that, their shot quality rapidly decreased this season. In terms of over-performing, Kalou has so far over-exceeded his goal-scoring expectations by close to 50% while Ibisevic has been fairly consistent. From their shot maps below, we can see why this over-performance might be happening:

Kalou generally takes shots from good areas of the pitch, although this season he has been tempted to shoot from distance. (Yellow = goals, Orange = miss/blocked/saved.)

 

Ibisevic is on the same level as his team-mate, yet just takes more shots than him. (Yellow = goals, Orange = miss/blocked/saved.)

 

To see how both players’ total performance profiles have changed over the two seasons, we turn to a radar graph. There are other ways this data can be shown but thanks to the guys @FussballRadars this was the most effective way. Both players’ metrics have decreased considerably since 2015-16.

Salomon Kalou passing radars from 2015-16 and 2016-17:

Salmon Kalou passing radar 2016-17. Source: @Fussballradars.

 

Salmon Kalou passing radar from 2016-17. Source: @Fussballradars.

Vedad Ibisevic passing radars from 2015-16 and 2016-17:

Vedad Ibisevic’s passing radar from 2015-16. Source: @FussballRadars.

 

Vedad Ibisevic’s passing radar from 2016-17. Source: @FussballRadars.

 

Passes

Unlike shots taken, Hertha are an average possession team finishing with the 8th most passes (457 on average per game) in the Bundesliga this season. That was just above the average number of 447 recorded per game. By the way, it is a decrease of 333 passes (approximately 10 per game) compared to last season, but that does matter? Not in the slightest!

Now passes alone as a number are one of those things that I would argue does not tell us much about a team. Sure, it might tell us how much possession a team enjoys, yet how do we measure the build-up of an attack using passes? One way would be to use Key Passes or even better Box Key Passes.

Opta, a sports data collection company, define key passes as “The final pass or pass-cum-shot leading to the recipient of the ball having an attempt at goal without scoring” (although Colin Trainor with this Statsbomb piece mentions a Key Pass as “regardless of the shot outcome.” Having collected an entire season’s worth of shot, key pass and box key pass data, I wrote about them back in December last year. Essentially, a high number of key passes would suggest a team looking to play the ball into shooting positions earlier, while a low number could suggest a more patient approach.

Hertha Berlin ranks low on the average Key Passes per match chart for the Bundesliga in 2016-17.

 

Hertha Berlin ranks higher in average “box” per passes per match in the Bundesliga during 2016-17.

As we can see, the data would suggest that Dardai uses slow build-up play, especially compared to other Bundesliga teams or even to the league average. While Hertha are low with building Key Passes, their direct attacks (Box Key Passes) into the box show intend to move the ball faster up the pitch and into good shooting locations. However, if we compare it to last season, Hertha had 9 more key passes yet 8 fewer box key passes. What can we take away from this? Well the increase in key passes aligns with the increase in shots from outside the box (as per my definition).

Defense

Defensively, Hertha have performed near to exact how xG would have expected them to. 2015/16 they were 42 goals to 42 xGA and this season again just slightly over (47 goals to 45 xGA). Their shots conceded have increased by just over half a shot per game, so we can say that they are to an extend defensively strong. I say to an extend because they do receive the old hammering from teams from time to time (RB Leipzig and Bayer Leverkusen).

Breaking the shots down into zones or areas could help examine where Hertha have conceded more shots and goals from in comparison to last year. The increase in half a shot per game for the 2016/17 season can be attributed to Hertha allowing their opponents predominately more shots in the “wider areas” of the 18-yard box. Every other zone, as I have it broken down by, is virtually or nearly the same as the year before.

New Signings

At the time of writing the article, Hertha had already been busy in the transfer market. They bought Mathew Leckie (FC Ingolstadt), Davie Selke (RB Leipzig), Karim Rekik (Marseille), and elevated youth academy players (Julius Kade and Jordan Torunarigha) to the first team. What are these players going to bring to the squad?

Let’s start with Leckie. He will bring a bit of youth to Dardai’s attacking options at the very least, after all he is only 26. Anything else? From a physical side, he is strong in the air and can play in several different attacking positions. What about from a statistical stand-point?

Player 2015/16 2016/17
Minutes/Shots Taken/Per 90 Minutes/Shots Taken/Per 90
Matthew Leckie 2476 / 39 / 1.42 2087 / 49 / 2.11

Leckie is not a bad signing for Hertha. Even though he played less this season, he has contributed more shots per game than the season before. Now this won’t be the only thing Hertha would have looked at and said SIGN HIM! It’s just an example of what metrics we can use to examine why he was of interest to them. From a xG perspective, I had Leckie down as scoring 5.82 xG. Sadly, he didn’t score a single goal this term but he did create 3 assists. His shot map is decent, so I would assume given the chance, he should contribute nicely to the Hertha Berlin attack.

The location of Matthew Lekie’s goals in 2016-17 (with Ingolstadt).

Dardai bringing Selke into the team has huge potential to bolster Hertha’s attacking options. This move also shows that Dardai possibly recognized his aging strike force and decided that at 22 years of age, Selke was the perfect fit. Last season, while he made 21 appearances, he only started two games. In that sense, he did not exactly play a lot of football, just 436 minutes to be exact.

In those 436 minutes played, he took 14 shots, scoring 5 goals in contrast to his 1.9 xG. On a per 90, basis this rate equaled 2.89 shots and 1.03 non-penalty goals and 0.39 xG. Due to these low numbers, it’s not exactly certain what we can expect from Selke over the course of more minutes played. What I will say is from a statistical perspective, that’s a pretty audacious signing. However, stats should never be the only recruitment tool used to evaluate potential signings.

The location of Selke’s shots during 2016-17 (orange dots = goals).

I don’t particular know much about Rekik so I asked Twitter. The consensus there was not much better. He’s been around the championship teams, the Eredivise with PSV and now Marseille in Ligue 1. He played 10 games last term so not a lot but gives Dardai another option at centre-back. Either way, the competition for a centre-back starting position nevertheless gets heated again.

Who’s next?

Ah yes, the two academy prospects Kade and Torunarigha. Now I don’t know much about both of them but then again there’s always Google. First up, Kade. The 17-year-old sat on the bench for 8 games this season and was called upon for 9 minutes in the 1-0 away loss to Gladbach. He can play in several positions in midfield but is most prominent as a No. 10. I don’t expect him to play a lot next year (unless injuries take a massive hit to the squad) but a few more substitute appearances should definitely be on the cards.

Torunarigha (19) on the other hand played a couple more games, 8 to be specific and got on the scoresheet once (away to Darmstadt). Now that John Brooks has left to join Wolfsburg; it is the perfect time for Torunarigha to step in. If successful with consistent performances, the Hertha faithful will be more than happy to forget Brooks (who wasn’t always the most consistent centre-back).

Europa League & Conclusion

Based on my observations in this article, Hertha Berlin have over-performed in their attacking out-put while defensively being consistent to expected goals. In addition, the extra Thursday night games will take their toll on a team with a squad depth like Hertha. They need to bring in some more quality players, preferably with Europa League experience. The summer is still young so expect the unexpected with transfers. Regardless of the fact, I still think Hertha will challenge for Europa League but might possibly miss out due to the new experiences of the EL this next season. I don’t think they’ll be struggling for Bundesliga survival like in 09/10 when they qualified for the Europa League the season before (2008-09).

Feel free to access the Bundesliga Tableau document here.

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A South African by birth, the bilingual (English and German) Alex has called many places home (South Africa, Ireland, Germany, and U.S.). In college, he studied sports performance. In his work as a data analyst (mainly football and rugby), Alex relied on this training in developing his Expected Goals model, his Goalkeepers dashboard, or other goodies on his Tableau profile. You can follow him @AlexRathke.

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