Are Premier League referees biased against Arsenal? (Part 1)

In the wake of yet another contentious penalty decision given against Arsenal, I thought it would be interesting to dive into the numbers to see whether Premier League referees do actually discriminate against Arsenal at either end of the pitch.

This is by no means going to be a comprehensive analysis of each individual decision and whether they were right or wrong. Rather, I'll be attempting to look into the number of penalties awarded and conceded over time, and seeing how they compare to other clubs, and against what we'd expect for a team of Arsenal's style and stature. This is partly to open our eyes to the potential influence of footballing reasons, and partly because looking at the refereeing errors affecting one club in isolation doesn't tell us anything about bias - ALL clubs suffer from bad decisions to some degree and ALL fans complain about decisions that go against them; looking at one club alone couldn't possibly tell you anything about whether they receive different treatment to other clubs.

This first part will focus on penalties awarded. In order to be thorough, data from the 10 seasons between 2007/2008 and 2016/2017 will be used, from the 22 teams that have featured most frequently in that time.

All statistics are sourced from OPTA, via Statbunker and Whoscored.

The most basic stat to start off with is the actual number of penalties awarded per season. In the following table you can see that Leicester surprisingly top this list, thanks in part to their haul of 13 awarded penalties in their title-winning 15/16 season. The top of the table is otherwise dominated by the league's strongest teams, with the exception of Arsenal all the way down in 9th place, and Blackburn and Crystal Palace way up in 6th and 7th.



Now penalties in isolation don't tell you much. To get a better idea of whether a team is winning too few penalties, we need to look at their general attacking threat. Well non-penalty goals is a good gauge of how potent a team's attacking threat is (and is independent of potentially biased penalties).  Arsenal top this list over the last 10 years, which produces quite an odd contrast with their lowly penalty figures. Definitive proof of refereeing bias right?

But Arsenal are not the only team who are under-represented. Swansea and Southampton would also have legitimate claims to be the victims of refereeing bias if we were to use this simple logic. And the likes of Leicester, Crystal Palace and Blackburn would appear to be enjoying the favour of referees.

To get a better idea of the discrepancy between a team's rank in the penalties awarded category and the non-penalty goals category, we can express the former as a percentage of the latter. This gives us a very nice spectrum as shown in the following table, with the likes of Crystal Palace and Leicester sitting at the top, winning penalties at more than double the rate (relative to their attacking level) of Arsenal, who sit at the very bottom.



Now, far from reinforcing the idea that referees are biased in favour of or against certain teams, this table actually goes a long way to explaining the footballing reasons behind this disparity. The top of the table is dominated by teams that could broadly be described as playing direct football, be it Leicester's lightning quick counter-attacks, Palace's tricky winger-based system, or Stoke and Blackburn's physical, aerial game. At the other end of the spectrum you have Arsenal and Swansea, two teams renowned for playing short-passing, possession football. And then in the middle you have the traditional big teams - minus Arsenal of course. These teams tend to dominate possession perhaps by virtue of their quality rather than by design, and they are not necessarily wedded to a slow, intricate approach.

On the face of it this contrast would make sense - penalties are often won during transitions, when tricky, pacy attackers can take advantage of opposition disorganisation, isolating defenders and drawing them into desperate fouls in the box. Teams that move the ball quickly from back to front are likely to win more penalties at any given level.

So the next table looks at a team's "directness", measured as the percentage ratio of long passes to short passes. Directness also correlates incredibly well with average possession, as you'd expect.

From this table we can see that there's a pretty clear trend of penalty % increasing as directness % increases. It's not a perfect trend of course, as Wigan seem to win more penalties than you'd expect for a team of their style, and Bolton have won far less than you'd expect with their direct approach, to name just 2 outliers.



So what does this data tell us? That there's a pretty good correlation between a team's directness, and the likelihood of them winning penalties at their particular quality level. The following graph demonstrates this better:



But this doesn't explain everything. Why, for example, do Man City win so many penalties for such an indirect team, while Arsenal win so few? Why are Arsenal awarded penalties at the rate of a mid-table team while their rivals at the top all earn considerably more despite not being that much more direct than Arsenal?

You would of course expect good dribblers at top clubs to also win penalties in crowded boxes, so directness cannot FULLY account for the penalty rates. Hence why the top clubs such as Man Utd, Chelsea, Liverpool and Man City hover around midtable for the penalty award rate, despite being at the bottom of the table of directness. Arsenal don't seem to benefit from this effect.

To illustrate this point one final time, let's compare average points per season to the penalty % rate below. You can see that the top 7 cluster all win significantly more penalties relative to NPG than Arsenal.



What can we conclude from these numbers? Firstly, this DOES NOT prove that referees are biased against Arsenal. This analysis is nowhere near exhaustive enough to be able to confirm that point of view. As we've seen, just a quick dive into the possession/directness figures has already uncovered one significant factor that affects how often different clubs are awarded penalties. There's no reason to think that a more detailed analysis of other metrics wouldn't uncover any more insights.

With that being said, there is room within the data for potential refereeing bias. This doesn't necessarily have to be an intentional bias, or the result of a conspiracy among referees. It could be something as simple as a sub-conscious stereotype of Arsenal as a 'soft' team who go down too easily under challenges. Again, the data above doesn't prove this, but doesn't rule it out either.

Part 2 will focus on penalties conceded, which should give us another angle to approach the issue from, and more data to add to the playing style vs refereeing debate.

Best Historical Attacking Seasons

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Arsenal Attacking Statistics 2017/2018

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Arsenal Attacking Statistics 2012/2013

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Arsenal Attacking Statistics 2000/2001

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Standout attacking performances:

Patrick Vieira
2 goals, 1 assist
Arsenal 5-3 Charlton Athletic (Premier League)

Ray Parlour
3 goals
Arsenal 5-0 Newcastle United (Premier League)

Sylvain Wiltord
1 goal, 2 assists
Arsenal 5-0 Manchester City (Premier League)

Sylvain Wiltord
3 goals
Arsenal 3-0 West Ham United (Premier League)

Thierry Henry
2 goals, 1 assist
Arsenal 5-0 Manchester City (Premier League)

Thierry Henry
3 goals, 2 assists
Arsenal 6-1 Leicester City (Premier League)

Barcelona Attacking Statistics 2001/2002

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Arsenal Attacking Statistics 1999/2000

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Standout attacking performances:

Davor Suker
2 goals, 1 assist
Arsenal 4-1 Everton (Premier League)

Dennis Bergkamp
2 goals, 1 assist
Arsenal 5-1 Middlesbrough (Premier League)

Marc Overmars
3 goals
Arsenal 5-1 Middlesbrough (Premier League)

Marc Overmars
1 goal, 2 assists
Arsenal 3-1 Blackpool (FA Cup)

Nwankwo Kanu
3 goals
Chelsea 2-3 Arsenal (Premier League)

Ray Parlour
3 goals, 1 assist
Werder Bremen 2-4 Arsenal (UEFA Cup)

Thierry Henry
2 goals, 2 assists
Arsenal 4-1 Sunderland (Premier League)

Thierry Henry
2 goals, 1 assist
Watford 2-3 Arsenal (Premier League)

Thierry Henry
2 goals, 1 assist
Arsenal 5-1 Deportivo (UEFA Cup)

Arsenal Attacking Statistics 1998/1999

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Standout attacking performances:

Dennis Bergkamp
2 goals, 1 assist
Arsenal 3-0 Newcastle United (Premier League)

Dennis Bergkamp
1 goal, 2 assists
Arsenal 3-1 Leeds United (Premier League)

Dennis Bergkamp
4 assists
Arsenal 5-0 Leicester City (Premier League)

Luis Boa Morte
1 goal, 2 assists
Preston North End 2-4 Arsenal (FA Cup)

Marc Overmars
1 goal, 2 assists
Middlesbrough 1-6 Arsenal (Premier League)

Nicolas Anelka
3 goals
Arsenal 5-0 Leicester City (Premier League)

Nicolas Anelka
1 goal, 2 assists
Arsenal 3-0 Manchester United (Charity Shield)

Nwankwo Kanu
2 goals, 1 assist
Middlesbrough 1-6 Arsenal (Premier League)

Stephen Hughes
3 assists
Arsenal 3-0 Manchester United (Premier League)

Arsenal Attacking Statistics 2015/2016

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Standout attacking performances:

Alexis Sanchez
3 goals, 1 key pass
Leicester 2-5 Arsenal (Premier League)

Alexis Sanchez
2 goals, 1 key pass
Arsenal 3-0 Manchester United (Premier League)

Alexis Sanchez
3 key passes
Arsenal 4-0 Aston Villa (Premier League)

Alexis Sanchez
2 goals, 1 assist
Arsenal 3-0 Dinamo Zagreb (Champions League)

Mesut Ozil
1 assist, 3 key passes
Leicester 2-5 Arsenal (Premier League)

Olivier Giroud
3 goals
Arsenal 4-0 Aston Villa (Premier League)

Olivier Giroud
3 goals
Arsenal 3-0 Dinamo Zagreb (Champions League)

Theo Walcott
2 goals, 1 assist
Hull 0-4 Arsenal (FA Cup)

Arsenal Attacking Statistics 2016/2017

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Standout attacking performances:

Alex Oxlade-Chamberlain
1 goal, 1 assist, 2 key passes
Arsenal 6-0 Ludogorets (Champions League)

Alexis Sanchez
3 goals, 1 assist
West Ham 1-5 Arsenal (Premier League)

Alexis Sanchez
1 assist, 2 key passes
Basel 1-4 Arsenal (Champions League)

Alexis Sanchez
1 goal, 1 assist, 2 key passes
Arsenal 5-0 Lincoln City (FA Cup)

Danny Welbeck
2 goals, 1 assist
Southampton 0-5 Arsenal (FA Cup)

Lucas Perez
2 goals, 1 assist
Nottingham Forest 0-4 Arsenal (EFL Cup)

Lucas Perez
3 goals
Basel 1-4 Arsenal (Champions League)

Lucas Perez
1 assist, 2 key passes
Southampton 0-5 Arsenal (FA Cup)

Mesut Ozil
3 goals, 1 assist
Arsenal 6-0 Ludogorets (Champions League)

Mesut Ozil
1 goal, 1 assist, 1 key pass
West Ham 1-5 Arsenal (Premier League)

Mesut Ozil
1 assist, 2 key passes
Basel 1-4 Arsenal (Champions League)

Olivier Giroud
1 goal, 2 assists
Bournemouth 3-3 Arsenal (Premier League)

Theo Walcott
3 goals
Southampton 0-5 Arsenal (FA Cup)

Robin van Persie 2010/2011

Season Stats:

26 starts + 7 sub apps

22 goals

7 assists

1 key pass

Premier League Stats:

18 goals

-Highest at Arsenal; 3rd highest in PL (Berbatov/Tevez 20)

3.4 shots per game

-Highest at Arsenal; 3rd highest in PL (Sturridge/Suarez 3.6)

7 assists

-3rd highest at Arsenal (Arshavin/Fabregas 11)

1.8 chances created per game

-3rd highest at Arsenal (Fabregas 2.9)

0.7 successful dribbles per game

-Highest of Arsenal strikers

1.1 clearances per game

-Highest of Arsenal strikers

High Point

Scored the equalising goal at home against Barcelona in the Champions League 2nd round. Going into the game on the back of a rich vein of goalscoring form, van Persie proved his big-game credentials with a superb near-post volley that caught Victor Valdes by surprise and gave Arsenal the belief to go on and grab the winner, which they duly did.

Low Point

Sent off in the return leg of the Champions League 2nd round tie at the Camp Nou. The Dutchman had endured a frustrating evening as Arsenal struggled for long periods to pass the ball out of their own half, and after being booked for a push on Alves in the 1st half, van Persie received his marching orders in the 56th minute when he kicked the ball out of play a second after the ref had blown for offside. Arsenal's remaining 10 men buckled under the waves of Barcelona attacks and went out 4-3 on aggregate.

Marouane Chamakh 2010/2011

Season Stats

27 starts + 17 sub apps

11 goals

4 assists

5 key passes

Premier League Stats

7 goals

-4th highest at Arsenal (RVP 18)

1.4 shots per game

-6th highest at Arsenal (RVP 3.4)

4 assists

-5th highest at Arsenal (Arshavin/Fabregas 11)

1.4 chances created per game

-6th highest at Arsenal (Fabregas 2.9)

78% pass success rate

-2nd lowest of Arsenal outfield players (Arshavin 75%)

47% aerial duel success rate

-Highest of Arsenal centre forwards

1 tackle per game

-Highest of Arsenal centre forwards

0.7 interceptions per game

-Highest of Arsenal centre forwards

2 turnovers per game

-Highest at Arsenal

High point

Scored both goals in a tough away win at Wolves in the Premier League. Chamakh set a Premier League record by finding the net in both the 1st and 90th minute of the game, the 1st a trademark header from a cross, the 2nd a composed finish from a quick counterattack.

Low point

Partially at fault for Arsenal's comical home defeat to Tottenham in the league. After scoring in the 1st half to help put the Gunners two goals up, Chamakh twice spurned good goalscoring opportunities by turning back away from goal and passing to teammates, a feature of his game that was to become more apparent during his loss of form in the second half of the season.

Jack Wilshere 2010/2011, Part 2

Highlights of the young Englishman from January to March:

Wojciech Szczesny 2010/2011

Season Stats

24 starts

25 goals conceded

9 clean sheets

72 saves

Most saves in a game: 9 - Newcastle 0-4 Arsenal (LC)

High point

After spending a season on loan at Brentford, made a wonderful return to Arsenal duty with an incredible all-round performance away at Newcastle in the League Cup. His combination of aerial prowess, big frame and cat-like reflexes ensured that Arsenal left with a clean sheet and - more importantly - demonstrated that he was ready to establish himself as the club's no.1.

Low Point

Partially at fault for Arsenal's inability to see out their lead in the 3-3 draw at Tottenham in the league. Although the young Pole dominated his box and made some excellent saves throughout the match, he could have done better for Spurs' first two goals and gave away a cheap penalty for their equaliser.

Arsenal Funny Moments 2010/2011

Real Madrid Attacking Statistics 2011/2012

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Standout attacking performances:

Cristiano Ronaldo
3 goals, 1 key pass
Real Zaragoza 0-6 Real Madrid (La Liga)

Cristiano Ronaldo
3 goals
Real Madrid 6-2 Rayo Vallecano (La Liga)

Gonzalo Higuain
3 goals
Espanyol 0-4 Real Madrid (La Liga)

Gonzalo Higuain
3 goals
Real Madrid 4-1 Real Betis (La Liga)

Marcelo
1 goal, 1 assist, 1 key pass
Real Zaragoza 0-6 Real Madrid (La Liga)

Mesut Ozil
2 assists, 1 key pass
Real Madrid 6-2 Rayo Vallecano (La Liga)

Barcelona Attacking Statistics 2011/2012

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Arsenal Attacking Statistics 2011/2012

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Alex Song 2010/2011, Part 2

Season Stats

39 starts + 3 sub apps

5 goals

3 assists

7 key passes

Premier League Stats

79 tackles won (77% success rate)
-11 highest in league; 2nd highest at Arsenal (Clichy 90)

48% aerial duel success rate
-3rd highest of Arsenal midfielders (Rosicky 63%)

2.6 interceptions per game
-Highest of Arsenal midfielders; 4th highest at Arsenal (Vermaelen 3.6)

2 clearances per game

-Highest of Arsenal midfielders

0.4 shots blocked per game
-Highest of Arsenal midfielders

2.2 fouls per game
-Highest at Arsenal

0.9 opposition dribbles allowed per game
-4th highest of Arsenal midfielders (Denilson 1.6)

1 chance created per game

-8th highest at Arsenal (Fabregas 2.9)

1.1 successful dribbles per game

-5th highest at Arsenal (Diaby 2.3)

2 times dispossessed per game

-4th highest at Arsenal (Fabregas/Nasri 2.4)

High point

Grabbed a late headed winner against a stubborn West Ham side at the Emirates, after a good all-round display in the box-to-box role. Having started the move by spreading the ball out wide, Song made what was to become a trademark surge into the box, and nodded in Clichy's inswinging cross to the delight of Arsenal fans.

Low point

Sent off away at Sunderland in the league, forcing Arsenal to (unsuccessfully) defend an aerial onslaught with 10 men for the remainder of the match. Although the yellows seemed harsh, Song's habit of persistently conceding niggling fouls finally caught up with him, and Arsenal caved in when a high ball into the box in the 5th minute of stoppage time wasn't dealt with adequately.

Tomas Rosicky 2010/2011

Season Stats

19 starts + 15 sub apps

1 goal

5 assists

11 key passes

Premier League Stats

1 assist

-10th highest at Arsenal (Arshavin/Fabregas 11)

1.3 chances created per game

-7th highest at Arsenal (Fabregas 2.9)

0.5 accurate throughballs per game

-2nd highest at Arsenal (Fabregas 1.5)

0.7 times disposesssed per game

-11th highest at Arsenal (Fabregas/Nasri 2.4)

0.8 successful dribbles per game

-8th highest at Arsenal (Diaby 2.3)

63% aerial duel success rate

-3rd highest at Arsenal (Vermaelen 73%)

High point

Filled in expertly for Cesc Fabregas in the 6-0 demolition of newly-promoted Blackpool, with a master display of creativity. In a display that was reflective of his early season performances, Rosicky tore the Seasiders apart with his throughballs, providing key passes for 2 goals and a penalty which Arshavin converted.

Low point

Put in a shambolic defensive performance when subbed on during Arsenal's embarassing 4-4 draw at Newcastle. After Diaby's 2nd half dismissal, Rosicky was brought on to shore up the midfield but instead played Leon Best onside for a (disallowed) goal, gave away a penalty and conceded the freekick that led to Newcastle's equaliser.