Referee Review 2012/13: Chelsea. A bias against, but not always

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.


In this part of the series we have a look at each team and see how the bias panned out for each team. This is based on the decisions themselves without putting any weight on each decision. A total table will be published at the end of this series and then you can compare each team with the other teams.

And it will be an interesting table I can assure you of that.

First we are providing a table for each team highlighting each type of decision. This gives the totals as for when the team in the article got a favourable decision and when they got it against them.

If the traditional mantra, “it all evens out at the end of the season” is true it should show in these statistics – and indeed for some clubs we have already reviewed, that is the case.

But as I said, in the table we just show the decisions as a decision and we didn’t put any weight on the decisions. That is something for later on. Now we just take each decision at the same value, which is of course not saying all because a wrong penalty call is a bit more important than a wrong throw in decision.

But now let us move to the next team in our survey:


We did 28 games of Chelsea and that is 73,68%  of their games. A rather high number of games reviewed in fact. So unless the complete opposite of all we saw in our matches we can think that this should be the pattern for the whole season.


In the second column we see the type of decision. And in the column “Favoured” we see how many decisions favoured this team when we reviewed them.  In the column “Penalised” we see how many times a wrong decision went against them.  The total swing is the difference between the favoured decisions and the penalised decisions.

A negative number in this column means that the total was against the team and a positive number means that the total decisions was in their favour.

In the last column we see the average swing per game, based on the games we reviewed. And this gives an indication on how many decisions went against a team or were in favour of a team. The lower the number the lower number of decisions that were wrong. And a positive number indicates that in each game they get some decisions in their favour and a negative indicates how many decisions the team has to overcome.

We had a total of 349 wrong decisions in the 28 games we did with Chelsea.  That is around 12 wrong decisions per game. Again this is too high to be good.   But more importantly now is to see how the dividing was of those wrong decisions.

Of those 349 wrong decisions we had 169 in their favour and 180 going against them. The difference is 11 decisions going against Chelsea  in total. This is a bias against them. But a rather small bias against them. We have seen worse.

When we look at the decisions we see that they got some benefit from the free kicks, and offside decisions what we could call the small decisions. They also got a advantage of the bigger decisions like 2nd yellow cards, goals and penalties. Now I must say that the difference is not that big with only 1 decision more in their favour than against them.  But then again I think any fan would rather pick that position than being on the wrong end of the decisions.

If we look at the decisions going against them we see that this is more about the not that important decisions. We talk about the corner, free kick, goal kick and throw in decisions. And the only one that stands out is the yellow card decisions. So lots of yellow cards were given against Chelsea that were wrong. Or where the opposition should have been punished with a yellow card but wasn’t.

This is a bit the opposite of Everton in our last article. They seemed to have a good result but it turned out some important decisions went against them. For Chelsea we see that they got an overall negative bias but with some big decisions going their way.

I think this and the former result prove that you have to look in detail to see the complete picture. And that is just what we have tried to do all season long.

Editorial note: if you want to comment it is perhaps worth having a look at some of the background to this research in the articles below, if you have not come across Referee Decisions before.  We have had situations in which supporters of various teams have not done this, and made comments which, in retrospect they maybe wish they hadn’t.

4 Replies to “Referee Review 2012/13: Chelsea. A bias against, but not always”

  1. Overall not a big bias either way but 2 points.
    1 No account seems to be taken for % possession ie if a team has 80% then the fail ratio on
    Them would be higher this would also effect other stats.
    2 Who decides if the ref’s decisions were wrong?

  2. I think an article on deadline day transfers will prove more popular! 🙂

    New ‘keeper + Ozil and it’s early evening… Interesting night ahead of us. 🙂 🙂 🙂

  3. Kakatk,
    The reviews are conducted by qualified, experienced referees.

    The position stat is an interesting proposition but probably difficult to implement so the total number incorrect decisions is used alongside a weighted score to take into account the severity of the mistake.

  4. Come on walter, Tony

    Put an article about transfers, write nothing just the headline, we want some place to talk about tranfers

    Please delete the before comment, i wrote my email address instead of my name 🙁

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