Category Archives: Network Analysis

Arsenal vs Liverpool: passing network analysis

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Arsenal and Liverpool drew 2-2 at the Emirates, as Arsenal came back from two goals down. Below is the passing network analysis for Arsenal and Liverpool. More information on how these are put together is available here in my previous posts on this subject.

The positions of the players are loosely based on the formations played by the two teams, although some creative license is employed for clarity. It is important to note that these are fixed positions, which will not always be representative of where a player passed/received the ball. The starting eleven is shown on the pitch, while Enrique and Santos, who came on as substitutes are shown on the sidelines.

Passing network for Liverpool and Norwich City from the match at Anfield on the 19th January 2013. Only completed passes are shown. Darker and thicker arrows indicate more passes between each player. The player markers are sized according to their passing influence, the larger the marker, the greater their influence. Only the starting eleven is shown.

Passing network for Arsenal and Liverpool from the match at the Emirates on the 30th January 2013. Only completed passes are shown. Darker and thicker arrows indicate more passes between each player. The player markers are sized according to their passing influence, the larger the marker, the greater their influence. The size and colour of the markers is relative to the players on their own team i.e. they are on different scales for each side. The starting eleven is shown on the pitch, with the substitutes on the sidelines. Click on the image for a larger view.

The contrast between the two teams approach is apparent, with Arsenal dominating possession (62% according to EPL-Index), which is reflected in their much stronger passing links across the team. Much of Arsenal’s play went through Aaron Ramsey, who played a similar role to that played by Mikel Arteta in the reverse fixture, although Arsenal saw more of the ball in this match. Arsenal’s midfield-three of Ramsey, Wilshire and Cazorla combined very well and dictated the passing patterns of the side excellently.

For Liverpool, the story was slightly different. The side was happy to counter-attack, which meant that the usual recycling of possession in deeper areas was less prevalent than for example against Norwich. Most of Liverpool’s play went through Henderson and Gerrard (again Liverpool’s major passing influence), with Johnson and Downing providing good support down the left and right flanks respectively. Daniel Agger was also able to influence the game from deeper positions, with his passing influence score being third behind Gerrard and Downing. Suárez was reasonably involved, combining well with Agger, Johnson and Henderson.

Hymns & Arias

In terms of passing influence, Ramsey was the undoubted star of the show. He conducted Arsenal’s play from deep beautifully, completing over 100 passes in the process. Obviously this was partially a result of Liverpool’s approach, which allowed him the time and space to dictate play but he combined well with Arsenal’s attacking players throughout the match. Gerrard was the major influence for Liverpool, while Jordan Henderson provided a passing option higher up the pitch and brought Downing, Suárez and to a lesser extent, Sturridge into the game. This was an important function in the team’s counter-attacking.

Liverpool delivered a different passing performance in this match. There are many parallels with the Everton match here, where Liverpool had a similar passing network and employed a more pragmatic counter-attacking style. It will be interesting to see if they use such tactics in the next match against Manchester City

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Liverpool vs Norwich City: passing network analysis

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Liverpool beat Norwich City 5-0 at Anfield while posting some impressive passing statistics. I’ve previously used network analysis to assess Liverpool’s passing this season. It has been a while since I last posted something on this but now seemed a good time to get back to it.

Below is the passing network for both Liverpool and Norwich City. The positions of the players are loosely based on the formations played by the two teams, although some creative license is employed for clarity e.g. Suárez’s position is shifted left-of-centre. It is important to note that these are fixed positions, which will not always be representative of where a player passed/received the ball. Only the starting eleven are shown in this instance.

Passing network for Liverpool and Norwich City from the match at Anfield on the 19th January 2013. Only completed passes are shown. Darker and thicker arrows indicate more passes between each player. The player markers are sized according to their passing influence, the larger the marker, the greater their influence. Only the starting eleven is shown.
Liverpool: Jones (1), Johnson (2), Agger (5), Carragher (23), Wisdom (47), Lucas* (21), Gerrard (8), Henderson* (14), Suárez (7), Sturridge* (15), Downing (19)
Norwich: Bunn (28), Garrido (18), R Bennett (24), Turner (6), Martin (2), Johnson (4), Tettey (27), E Bennett* (17), Howson (8), Snodgrass* (7), Holt (9)

There is a stark contrast between how the two teams approached passing the ball. Looking at Jones, the back four and Lucas, there are a multitude of connections between them as Liverpool aim to build from the back. Furthermore, Henderson and Gerrard are heavily involved in this area as the team aims to recycle possession – look at the strong links between them, Lucas and the centre-backs. This is completely missing in Norwich’s network as they sought to be more direct – see the long link between Bunn and Holt for example. Norwich created relatively little during the game and it is clear from their passing network that Holt was fairly uninvolved. I’ll not delve into Norwich’s passing network any further.

Sharing the load

An important diagnostic for network analysis is a measure known as “closeness centrality”, which in this context is dictated by the number of passes played and received by a given player. The higher the value the better and this can be thought of as the “passing influence” that a player has on their team. The absolute values aren’t important in this instance* so the main thing to look at is the relative size of the circles for each team. One of the major aspects of Liverpool’s network is that all of the outfield players aside from Sturridge were heavily involved in the passing movements of the team. Sturridge’s lesser involvement isn’t a criticism as such, as he clearly combined well with Liverpool’s more advanced players. In some ways, strikers can be disadvantaged by such a measure as they have less opportunity to get involved with everyone in the team, which can also be the case for goalkeepers. A more even distribution of passing responsibilities allows a side to create multiple attacking angles/opportunities – notice the large level of criss-crossing of the networks for Liverpool’s attacking players. Liverpool’s front-five plus Glen Johnson had a large amount of interplay with able support from Wisdom and Lucas.

O Captain! My Captain!

However, there was clearly a stand-out performer in terms of passing influence as Steven Gerrard dominates the passing network for Liverpool. Gerrard was the hub of the team’s passing. This combined with the rest of the team stepping up to the (passing?) plate, meant that Liverpool delivered an excellent passing performance. Whether they can continue this level of performance over the coming games will be crucial.

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*At some point I want to put these measures into a more quantitative context, which will hopefully add further detail regarding how Liverpool’s passing develops. 

West Bromwich Albion vs Liverpool: passing network analysis

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Liverpool began their season with a disappointing result against West Bromwich Albion at the Hawthorns. Much has been made since Brendan Rodgers’ appointment about his passing philosophy, so the focus here will be upon analysing how Liverpool passed the ball against West Brom.

Passing network analysis

One method of analysing passing by a football team is network analysis, which I’ve used previously to assess Liverpool’s passing against FC Gomel. The idea with network analysis is that the connections between players are analysed to look at passing patterns in the team and to identify key players in the network in terms of passing. The number of passes played and received by each player is collated according to the player they passed to and who they received from respectively. The data for passes played and received is taken from the Stats Zone application, which was kindly provided by the excellent Anfield-Index. One caveat to note is that throw-ins are included, which boosts Johnson and Kelly’s passes completed in particular.

Below is the passing network for Liverpool and shows completed passes only. The larger and darker the arrow is, the greater the number of passes played by one player to another. The positions of the players are based on their average positions during the match provided by WhoScored, although Lucas and Allen are slightly separated horizontally for clarity as their average positions were practically next to each other. It is important to note that these are the average positions, which will not always be representative of where a player passed/received the ball. Also, only the starting 11 is shown as the substitutes had a fairly limited impact upon the game in terms of passing.

Passing network for Liverpool from the away match against West Bromwich Albion on the 18th August 2012. Only completed passes are shown. Darker and thicker arrows indicate more passes between each player. The position of each marker is based upon their average position and the size of each marker is related to their closeness centrality, which is described in the text below. Asterisk indicates players who did not play the full match. Only the starting eleven is shown.

The main features in the above network are the reciprocal passes played between the defenders and the criss-crossing of passes in the midfield zone. Liverpool clearly kept the ball efficiently in deeper areas as the back four plus Lucas and Allen retained the ball well. The main issue for Liverpool was getting the ball to their attackers further up the pitch. Borini and Downing received the ball just 31 and 33 times respectively, with Downing in particular tending to pass the ball back to players in deeper areas; Downing completed a pass to Suárez twice and Borini once. Borini tended to combine with Johnson and Suárez in the main, passing to both of them on 7 occasions. Liverpool did effectively get the ball to Suárez, as he received the ball on 51 occasions and he was Liverpool’s main attacking outlet. Suárez tended to receive the ball from players in wide areas and from Lucas and Allen, whereas against Gomel the main link was with Gerrard and the quick interchanging of passes between them was less in evidence sadly.

Where you gonna pass to now, where you gonna go?

One of the useful tools of network analysis is that you can derive measures that indicate which players in the team are the most influential in terms of passing. One of these measures is known as “closeness centrality”, which in this context is dictated by the number of passes played and received by a given player. The key aspect of this measure is that it is greater when the passes that the player plays and receives are distributed more evenly across the team. If a hypothetical player makes 100 passes in a match and receives the ball 100 times, they would have a greater closeness centrality if they passed and received the ball 10 times to and from each team-mate compared to if they simply passed the ball back and forth to just 1 team-mate. Players with a larger closeness centrality score are interpreted as being a greater influence upon the passing of the team as they dictate the movement of the ball within the side.

In the figure above, the size of the player markers is dictated by their closeness centrality score. Joe Allen was Liverpool’s stand out player as he dictated Liverpool’s passing play. He generally received the ball from his centre-backs and Johnson prior to playing his passes. He linked well with Johnson and Borini on the left, his midfield partner Lucas and Suárez further forward. A feature of Allen’s play was his movement to make himself available for a pass and he received a pass on 62 occasions, more than any other player.

Skrtel had the next highest closeness score, although he was some way behind Allen. Agger was far less effective compared to the Gomel match, partly due to the sending off but also due to his passing recipients being lesser in scope as he favoured passes to Johnson, Skrtel and Allen. Lucas was also less of an influence, again partly due to not playing the full game but also due to being less central to the teams passing. Johnson was more effective than Kelly from full-back and was probably Liverpool’s most influential attacking force as he played high up the pitch on the left and created 3 scoring opportunities according to the EPL-Index Stats Centre. Downing and Borini’s involvement was very limited compared to their team-mates (only Reina was less involved). The involvement of Suárez and Gerrard was also disappointing. Overall, the lack of involvement of Liverpool’s front-4 was a hindrance over the course of the match, as most of the play was contained in the defensive and midfield zones.

Hey Joe

Liverpool’s passing against West Brom was reasonable, particularly in the 1st half and there were definite signs of Brendan Rodgers’ philosophy bedding in. However, the lack of involvement of the front-4 and in particular, Borini and Downing was disappointing. The major bright spot was the performance of Joe Allen, who dictated the passing play of the team to good effect. Unfortunately, Lucas wasn’t up to his usual level, which may be due to his ongoing recovery from injury and also this match being the first time he started with Allen. Hopefully future games will see this partnership blossoming as they begin to complement each other in terms of their roles within the team. Such a partnership could be crucial in implementing the control that Brendan Rodgers desires.

Passing Network Analysis: Liverpool vs Gomel

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Football is a simple game based on the giving and taking of passes, of controlling the ball and of making yourself available to receive a pass. It is terribly simple.

The above quote by Bill Shankly is one of my favourites regarding football and the passing style associated with Liverpool football club. The question is whether there is a way of assessing this “simple” aspect of the game that Shankly speaks of?

Passing network analysis

A method of assessing passing within a team that has been increasingly used in football, is network analysis. This treats players as “nodes”, through which passes connect each player within the team. The number of passes played and received by each player is collated according to the player they passed to and who they received from respectively. Using this, you can examine who passes to a particular player and who they pass to themselves, along with how often they do this.

Below is an example of such an analysis from the Liverpool vs Gomel match in the UEFA Europa League from the 9th August 2012. The data is for Liverpool and shows completed passes only. The larger and darker the arrow is, the greater the number of passes played by one player to another. The positions of the players is based on the rough formation that I thought Liverpool played in (I think Skrtel and Agger might have been higher up the pitch but the diagram is clearer if there is more space between players).

Owing to a lack of official statistical resources, I manually collated the passing data for each member of the Liverpool team, which was quite time consuming! Unfortunately, the on-demand replay of the game from ESPN was missing 5 minutes towards the end of the match, so there are some passes missing. After checking the completed passes data collated by the dedicated and excellent Anfield-Index in this piece with what I collated, I only missed up to 5 extra completed passes for some players, which shouldn’t make too much of a difference to the analysis.

Passing network for Liverpool from the home match against Gomel. Only completed passes are shown. Darker and thicker arrows indicate more passes between each player. The position of each marker is approximate and the size of each marker is related to their closeness centrality, which is described in the text below. Passing data was collected manually.

One of the key themes in the network above is the apparent prevalence of 3 or 4 players interchanging passes in different areas of the pitch. For instance, Reina often played the ball to his centre-backs, who often dropped deeper and wider to collect the ball, where-after they often recycled the ball between themselves. Further up the field, the centre-backs would form triangles with their full-back and nearest midfielder (often Lucas). You can also see this to an extent on the left-hand-side where Enrique, Borini and Gerrard linked up.

Another key feature, particularly in wide areas was the number of passes played back and forth between two players, which was used to retain possession and to advance the ball further upfield; note the reciprocal arrows between Agger-Enrique, Enrique-Borini, Skrtel-Johnson and Johnson-Downing. Borini in particular often received the ball and then played it back first-time to whoever passed it to him. The relationship between Suarez and Gerrard in the final third was also evident watching the game with lots of short passes between each other with excellent movement thrown in for good measure. This connection is evident in the passing network, with Suarez being Gerrard’s most frequent target with his passing and vice-versa.

Metronomic

The above gives an idea of how the passing network fits together as a whole but there are several measures that can assess which are the most important parts of the network. One such measure is known as “closeness centrality”, which in this context is dictated by the number of passes played and received by a given player. Crucially, this measure is greater when the passes that the player plays and receives are distributed more evenly across the team. So for instance, if a player makes 100 passes in a match and receives the ball 100 times, they would have a greater closeness centrality if they passed and received the ball 10 times to and from each team-mate compared to if they simply passed the ball back and forth to just 1 team-mate. Players with a larger closeness centrality score can be interpreted as dictating the passing network by having an impact upon the movement of the ball around the team.

In the figure above, the size of the players marker is dictated by their closeness centrality score. Daniel Agger, Lucas Leiva and Steven Gerrard are Liverpool’s major performers on this score. Agger outscored Lucas partially due to their differing passing accuracy (98.8% vs 90.8% according to Anfield-Index) as they received the ball a similar amount but Lucas misplaced more passes. Lucas’ accuracy may well increase as his match fitness increases. Gerrard was clearly the play-maker in the attacking third with good link up between Borini and Suarez along with spreading the play to Enrique and Johnson as they overlapped from full-back. This distribution throughout the spine of the team represents a potentially beneficial division of responsibilities; having a single player with a much larger centrality score could have negative consequences as a team can become overly reliant on a single player.

Such players are likely to be crucial to the style of play favoured by Brendan Rodgers this season. Agger and Lucas in particular had a strong linkage, acting as the fulcrum of the team in the recycling and transition phases of play. Higher up the pitch, Gerrard dictated play in the attacking phase, often linking with Suarez quickly and dangerously. Liverpool’s prospects this season may well depend on fielding these players together, something that didn’t happen at all last season.

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If anyone knows of any sources which collate passes played and received by each player then please let me know in the comments. I don’t have access to Stats Zone unless they launch an Android version and I would be interested in looking at these networks more as the season progresses. I don’t have the time or inclination to collect these manually over the course of the season; once was more than enough!