This weekend saw MLS lose two of its most talented players to broken legs that were the results of two awful challenges.  As someone who watches a lot of Arsenal matches, this is an all too familiar story.  My initial reaction was that the refs let too much go both in the EPL and MLS.  In MLS I’ve seen players get away with some awful tackles without a booking and often times without a foul even being called. Contrast this with La Liga where the slightest bit of contact will draw a foul, to the point where the game becomes agonizingly slow because of the constant whistles.  I wanted to look at the timing of cards across the major European Leagues and MLS to see if there were any obvious patterns.  I was expecting to see noticeably lower cards in MLS compared to other leagues as well as fewer cards handed out in MLS early on in the match due to refs letting things go in lieu of taking control of the match.

I looked at cards awarded per match for the big four European leagues plus MLS from 2006-2011.  Immediately apparent is that Serie A and La Liga have a larger number of cards than the EPL, MLS and Bundesliga.

Next I looked at the times cards were awarded.  For visual purposes, I excluded cards in the 45th and 90th minutes because of complications with injury time.  Cards are more frequently given out as the match goes on, with a bit of a grace period as the second half begins.  What I wasn’t expecting was that in the first few minutes, MLS awards cards at a rate consistent with La Liga and Serie A before slowing down to a rate similar to the EPL and Bundesliga.  Looking at the data at a per-minute granularity was too noisy, so I decided to bin the cards into 10 minute intervals to smooth things out.

After 10 minutes, the habits of La Liga/Serie A refs differentiate themselves from those of the other leagues.  I was surprised at the consistency across leagues and how the groupings were very obvious.  The one exception is that the behavior of Bundesliga refs differs from those of the EPL/MLS beginning in the middle of the second half.  I thought it was interesting that in all cases, leagues seemed to show an increasing number of cards, before leveling out a bit and then continuing the increase towards the end of the game.

Looking at the change in cards awarded between 10 minute intervals, the big difference between the two groups is that La Liga and Serie A give out a much higher number of cards in the first 30 minutes compared to that of the other leagues.  After that, the number of cards is relatively stable, excluding the end of the match and the Bundesliga second half increase.  What I find interesting is that the increased cards in La Liga and Serie A aren’t evenly distributed.  With the higher number of cards being shown early in the match, are refs being instructed to take control and prevent things from getting out of hand?  Could MLS and the EPL benefit from refs cautioning players earlier in the match?

Unfortunately, Steve Zakuani’s leg was broken in the 3rd minute so the ref never had a chance to prevent things from getting out of control.  However, the fact that Brian Mullan said afterwards that he has made that tackle 100 times and would do it again means that refs have let him get away with that sort of tackle 100 times.