REf Review 2012/13 : The bias that teams can get playing at home

By Walter Broeckx

This article is part of the series of the Referee Review 2013. You can find links to earlier articles on the bottom of this article.


On this site we have published all kinds of reports over the season 2012-2013.

We have dealt with the different teams. We have looked  closely at the refs themselves leading to the best ref election of the season according to the views and based on the numbers found by our referee reviewers.

We then had another look at the bias from the refs with each team.

The next step was looking at the 4 most important decisions on the football field that could have the biggest impact on the final result of games. We have shown this in the wrong decisions about second yellow cards, red cards, penalties and goals. And we did not only show which teams gained and how many times they gained, but also which teams suffered and how many times they suffered. Of course when the ref makes a mistake there is always a team that benefits but there is also a team that suffers from the wrong decision. So it is important to have a look at both sides of the medal.

Next to our seemingly never ending numbers coming out from our reviews we will show all the bias decisions that teams had to suffer last season in the matches we reviewed.

We showed you how many decisions went in favour of each team at home and how many decisions went against each team at home. A bit like we did with the important decisions. But in this table we will also show what that means for each team in relation to how many games we reviewed. We will do this by showing the average decision they faced each game we reviewed.

And in this article we will do this for the away games and then in a next article we will give you the grand total.

This is also important in the way that big decisions are sometimes more visible. More visible when the people who show games on TV allow them to be visible and this certainly goes for programmes on TV where they only show highlights. Cutting an important decision out of the highlights can make things look different.

So the numbers we will show you include the big decisions but also the more invisible little decisions bias. Things only the eyes of a trained person are likely to see and that mostly is overlooked by most fans in the stadium or even watching on TV.  These are the numbers that include the decisions  were referees know that you can go from a level playing field in to a biased playing field.

In the tables you are going to see we have for each team the numbers of decisions that favoured them and then we have the numbers when they were suffering from the wrong decisions from the ref. In the third column of numbers you then see the total swing. And in the final column you see the average swing taking in account the number of games we reviewed. And it is that number that we will focus on when we talk about the tables.

But let us first have a look at the numbers. The decisions for and against each team when they played away:

away swing

First thing we notice is that in this table we see a more even picture. This is another confirmation of the existing home bias. We now suddenly see that away from home more teams suffer from wrong decision compared to playing at home.  And when we look at some individual teams we also see that there is a difference for their numbers when playing at home or when playing away. And most of the time the numbers show that they are better of playing at home.

What a surprise Mr. Riley! Well maybe for you, no longer for us.

The team that benefited most from wrong decisions from the refs away from home is…Norwich. Who? Yes Norwich. For some reason refs have given them an awful lot of decisions in their favour when on the road. Now they haven’t had the highest number of decisions in their favour in total but this is based on the average per game playing away from home. So not really a big team bias at the top one could say.

But when we look at the number of decisions in their favour we see that Manchester United is the team that got most things going their way. This results in just under 4 decisions going their way on average in each away game. Remember at home just under 6 decisions and away it drops with 2 decisions. But a number that most teams would love to enjoy.

And just as with the home bias numbers we notice once again that this has nothing to do with big team bias. Because in 3rd place we find Stoke. They have benefited more than 3 decisions also on their travels. So theory that it is the atmosphere at the Brittania that forces refs to give them decisions is wrong. And then next in 4th place we have West Ham United.

When we look at the other top 4 teams we see that Manchester City, who had a little negative home bias against them now have a little away bias in their favour.  The team that finished in 3rd place, Chelsea has a negative bias away from home. They have to overcome 1 decision against them in each away game it seems.

And when we look at Arsenal we see that they have suffered the highest negative away bias of all teams. At home they have to overcome more than 7 decisions and away from home this rises up to just under 10 decisions per match going against them. If you compare this with let us say Manchester United this gives us a difference of 14 decisions between those teams.

And if we use the table from the home bias and compare this with the away bias from two teams you get an indication on how a team has to overcome the referee in some games. Let us take a match Manchester United – Arsenal. United has a positive home bias of +5.667 and Arsenal a negative bias of -9.632. That gives a difference of 15 decisions! Of course this is based on averages but that is what Arsenal has to overcome when they go to United.

Level playing field, Mr. Riley? You having a laugh!

In our next article we will look at the grand total of decisions and the total swing for each team both home and away. If you still can digest it.


Previous articles on referees…

The earlier series of reviews:

15 Replies to “REf Review 2012/13 : The bias that teams can get playing at home”

  1. Why don’t you do something about it then?
    You have the facts. Why aren’t they used to make the public and media aware?

  2. Very powerful data, which strongly supports gut feeling of MU given huge advantages while we tend to suffer. It’s strange it’s not more widely reported. The obvious objection of course being an Arsenal supporting site reporting huge refereeing against Arsenal…

    For credibility it’d be great to learn more about: 1) who is assessing the games? Several times it has been mentioned “the majority not supporting Arsenal”. For credibility sake it’d be great to be able to state that none of the reviewers assess the teams they themselves support; 2) do you have access to other recordings than those shown at live matches? Suppose not, but even if many key decisions are shown multiple times from various angles there are still quite a number of decisions where there is not good enough pictures to make the call. Does it then always count as the right decision by the referee or are those excluded from the denominator when calculating decision correctness?; 3) once you get a few replays it’s very often easy to see whether the call is correct. However, sometimes it’s not. Then I know you’ve written you always given the refere the benefit of the doubts, but there are still room for interpretation I guess (which could significantly impact the end result). A few high-profile examples could be enlightening to strengthen the understanding of how calls are made. Walcott penalty call on Chelsea for example. None of in total five experts (including two who are very much pro-Arsenal) on Swedish TV thought it was a penalty (contact, but not enough). How has that been judged/will it be judged? I suspect many of us Arsenal fans would say it’s a penalty. What would be the Untold assessment of that call? So a few such tricky key decisions from reviewed matches (covering several different teams) could potentially improve credibility.
    Keep up good and serious approach!

  3. cesc;

    Erm, what do you think they are doing? You are reading it on a blog, that gets numerous hits and is on the Newsnow feeds.

  4. Sunlight is the best disinfectant,” – U.S. Supreme Court Justice Louis Brandeis.

    And, although what Walter and co. have done would not be accepted in a court of law, one hopes that it will eventually help clear away the pungent odour frequently found around Premiership stadia.

  5. Some suggested fixes for football:

    1) Add another referee – Other sports have multiple referees and it doesn’t confuse the players or take away from a referee’s ability to control a game. The ability to see more of the pitch can only help the team get the calls correct. (The National Hockey League found that the game was getting too fast for one referee and that games were turning into a wrestling match on ice in the 1990s hence skilled players were being pushed out of the game. In addition, Canada and the US were losing ground to skilled European teams) The referees can always discuss decisions and if you designate one the head referee he can overrule his junior.

    2)Increase the number of referees and where they are from in England. La Liga has 20 or so referees and a serie A has more than 20 (22) with almost the same number doing a couple of games to get seasoning. The Bundesliga has 22. The premiership has 18 but three of them have done 5 or fewer matches. Not enough variety. And their regional origins are hugely biased toware the North and the Midlands.
    3) A study of the 2010-11 Premiership season found that the actual playing time was between 40 and 70 minutes ( not, of course, 90 minutes. 74% of the matches actually saw effective play in the 50-59 minute range. I would propose a 70 minute clock that was stopped for every stoppage in play thus taking the referee out of the equation. There would be NO TV timeouts.
    4) Add a sin bin. It could be the equivalent of a yellow or for continued small infractions. It could be for 5 or 10 minutes (like in rugby).
    5) Immediate foul for approaching a referee (except for a team captain)
    6) Add team fouls as a way to keep the game clean. A team should be punished for continually fouling another team. A recent study ( )had teams fouling on average about 12 times per match so that could be the threshold (but the number could be tinkered with in amateur football…say the Conference perhaps). In essence, if a team went beyond what was accepted or the norm in the league (fouls are called more in other leagues – close to 18 per match) they should be punished.
    7) Video replay. Since the clock is stopped it should be fairly easy to institute this especially for major decisions. It is patently ludicrous to think that a referee has diminished gravitas if it is seen that his initial decision was incorrect. What is more important the game itself and its result or the pride of an official? This should be handled through a league office.
    8) All suspensions should be accompanied by a detailed explanation as to the reasoning behind the suspension
    9) Increase the number of referees and where they are from in England. La Liga has 20 or so referees and a serie A has more than 20 (22) with almost the same number doing a couple of games to get seasoning. The Bundesliga has 22. The premiership has 18 but three of them have done 5 or fewer matches. Not enough variety. And their regional origins are hugely biased toware the North and the Midlands.


  6. I wonder what started this perceived hatred of Arsenal by the PGMOL and others. Could it be the honest workings of the Club, the style of play, an inferiority complex by Ferguson and his like? Could it even stem from the late 1930’s when Arsenal were the best in the land?

  7. Goinggoinggooner,
    an excellent comment.

    I think it could be used as a good basis to a complete article and then we could discuss your proposals better.

    Would you mind if we put it in an article?

  8. And how many times City is going to be lucky with offside decisions…. now again in the FA cup.. this is getting a bit ridiculous mr. Riley claiming 99% of offside decisions correct

  9. I am back into data accumulation mode after doing a bit of study of 1992/93 at the half way point. As I mentioned in some thread, there were 40 referees involved with the EPL in that first year, two of which only did a single game. The most any of them got was 19 games.

    UEFA recently started talking sin bin. I am not a fan of linear (or constant) penalization, it often not effective. I think time in the sin bin should scale as the square root of time remaining. Up to the 18 minute mark, its 9 minutes in the sin bin. From 18 to 34 minutes, 8 minutes in the sin bin. From 34 to 48 minutes, it is 7 minutes in the sin bin. From 48 to 60 minutes, it is 6 minutes in the sin bin. From 60 to 70 minutes, it is 5 minutes in the sin bin. From 70 to 78 minutes, it is 4 minutes in the sin bin. From 78 to 84 minutes, it is 3 minutes in the sin bin. After 84, it is 2 minutes (no more decrementing).

  10. @Walter 4:01 pm

    I would welcome a full article on this topic…you are far more qualified than I.

  11. Ok GoingGoingGooner I will take your comment and use that as a starting base for an article if not more 😉

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