Why Allow Referee Bias?

The latest Journal of the Royal Statistical Society has an article on soccer referee bias:

The statistical evidence seems to point to a home team bias in the incidence of disciplinary sanction. This interpretation is consistent with evidence of home team bias in several other recent studies, which find that the home team is favoured in the calling of fouls, or in the addition of stoppage time at the end of matches. Finally, evidence is found of variation between referees in the degree of home team bias, and this variation contributes to the overall pattern of inconsistency in refereeing.

Most people involved in sport know: home referees tend to be biased for the home team.  My colleague Alex Tabarrok similarly found that elected judges favor home plaintiffs against out-of-state defendants.

Why do we allow such biases?  We could force referees and judges to travel further so they didn’t cover home teams.   In sports, we could publicly evaluate and rate referees, via reviewing secret videotapes of random games.  Would such evaluations be too hard, or is the bias on purpose, because fans enjoy home game wins more than they dislike away game losses?

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  • http://profile.typekey.com/StatsGuru/ David Pinto

    “Most people involved in sport know: home referees tend to be biased for the home team. ”

    In the NFL, they use non-home team referees and there is still a home team bias. I don’t think it’s where the refs come from, I think it’s the influence of the crowd.

  • http://profile.typekey.com/robinhanson/ Robin Hanson

    David, your theory won’t explain judge bias very well, but perhaps referee and judge bias have different explanations.

  • G. Franczyk

    There are more variables being changed than just the city of origin of the referee.

    The away team’s discomfort of playing in a new city, the recent travel time to the away city, the effect of the hostile crowd all may cause the away team to not only underperform, but to not follow proper game play, and therefore more frequently be called on fouls and errors.

  • ernie

    The article seems to refer to referees being biased ‘for’ the home team, not that the referees themselves are from that city. In less-publicized matches, I can suggest that pleasing the home team is a good survival strategy. This is from personal experience!

  • who cares

    Let’s make sure that we’re not getting “bias” confused with “discrimination”. Bias is something that everyone is born with. You are biased about certain animals, plants and even foods that you eat. It is a natural survival skill. Sometimes bias is negatively influenced by outside circumstances or individuals which then leads to unnecessary discrimination. Referees’ bias are influenced by the crowd. The home team usually has more fans, which in turn gives a louder approval or disapproval of certain judgements made by the referees. Over the course of a game this can only be sure to grow. Although this may be somewhat unfair, let’s remember these are “GAMES” that we’re talking about and not very important social decisions. Lives will never be drastically affected by a biased call in a game. Let’s keep it all in perspective and also, let’s not get people all fired up and upset over something that really doesn’t matter anyway! Thanx for listening to my 2 cents.

  • http://bbnflstats.blogspot.com Brian

    Lots of fairly advanced econometric studies have been done on home field advantage in sports. The studies I recall show evidence that referee bias for home teams is small but measurable controlling for other important factors such as travel, field unfamiliarity, etc.

    I’ve wondered for a long time how innate racism is. It seems so universal that it must be something we are born with. It’s likely humans evolved to mistrust members of other clans for natural selection reasons. They do not share the same genes, so they would be seen as rivals for resources and reproduction opportunities. We might have innate negative feelings towards people who do not resemble us for that reason. Those feelings are probably strongest against those who are most different. If this is true, then “discrimation” and “bias” are the same thing.

    Am I just stating the obvious?

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  • http://overcomingbias ronald davidson

    i believe there is a bias against northeast teams when playing away.newcastle,sunderland and middlesbrough, it seems to me,get badly treated by referees and incidently,the media in general.i think our geographical location has something to do with it.split second decisions have to be made by the referee,and it is at these times when the bias comes in,although it may be regretted later.referees,though will not admit to mistakes.