Whitecaps the Dirtiest Team in Major League Soccer?

According to Major League Soccer's official team statistics, the Vancouver Whitecaps have conceded 442 fouls so far this season^[1]. This leads the league, and by a considerable margin. Therefore, the Vancouver Whitecaps are the dirtiest team in the league.

Well, no, if it were that damned easy I wouldn't have bothered writing an article. It's possible, of course. They certainly have players prone to fouls through carelessness or malice: Gershon Koffie, Martin Bonjour, and Jun Marques Davidson are all regularly-offending regulars. Some would add Darren Mattocks. All Major League Soccer teams have players like this, but the Whitecaps seem to have more than their share.

The first question is what we mean by "dirtiest team". If you think the dirtiest team is the one that takes the most fouls, then it actually is that simple and you can close the window. However, I think I more reasonable definition would be "the team with the largest difference between the number of fouls conceded and the number of fouls received". You wouldn't call a team dirty just because its games are strictly refereed and therefore both teams take a huge number of fouls. Likewise, if two teams are giving as good as they get in a really awful game it would be unfair to point to one team and say "they're the dirty one." And there are statistical reasons why a raw number of fouls over the course of a season in progress isn't a valuable measurement.

I went back through the Whitecaps' games through the course of the season, dividing them into home and away, and recording the number of fouls and cards in each game for both the Whitecaps and whoever their opponent was. The results are below.

You'll notice at a glance that there's a sharp home/away divide in fouls: almost as a rule, the away team concedes more fouls than the home team. This fits the prevailing research. Evidence shows that soccer referees are more lenient towards the home team^[2], and a 2006 study showed soccer referees feel their decisions are unconsciously impacted by a home crowd^[3].

Given that the Whitecaps have played two more road games than home games this season, this obviously makes a difference in their foul totals. Per game the Whitecaps suffer 1.286 more fouls than they concede at home this season, while on the road they concede 1.375 more fouls per game than they suffer. What this means is that, extrapolated to a 34-game season of 17 home games and 17 road games, the Whitecaps are on pace to concede 499.83 fouls and suffer 498.31: very nearly identical.

Short version: the Whitecaps foul the opponents no more often than the opponents foul them.

But the Whitecaps are still involved in an astonishingly large number of fouls every game. They are first in fouls conceded and second in fouls suffered and will lead the league in total fouls per game (conceded and suffered) by a country mile when the dust clears.

I do not have any easy explanations for why the Whitecaps are involved in so many more fouls than the rest of Major League Soccer. Some possibilities I can think of are:

1. The Whitecaps play dirty or clumsy soccer, and their opponents retaliate with additional dirty or clumsy soccer. This naturally leads to a large number of fouls spread between both teams.

   An extremely hasty look at the statistics contradicts this. The next-worst fouling teams, Sporting Kansas City, Real Salt Lake, and San Jose Earthquakes, all give away a large number of fouls without receiving a large number in return. Kansas City and San Jose have played an equal number of games home and away, Salt Lake has played two more games at home than away (which should increase their fouls suffered and reduce their fouls conceded).

   In short, if the Whitecaps being dirty inspires other teams to play dirtily, they're the only frequently-fouled team doing it. This doesn't mean that can't be the explanation; maybe the Whitecaps are unusually good at getting under an opponent's skin. It is, however, a point against it.

   A statistic in favour of the Whitecaps being unusually dirty is a markedly higher proportion of yellow cards. In games this year, the Whitecaps are averaging a yellow card every 6.60 fouls conceded, whereas their opponents are averaging a yellow card every 9.32 fouls. The Whitecaps average more yellow cards per game in BC Place (2.00) than their opponents (1.71), when it's the road team which has the crowd against it and is often trying to slow the game down.

2. The Whitecaps are victims of a disproportionate amount of dirty or clumsy soccer, and retaliate with dirty or clumsy soccer of their own. This is a stupid theory for all the reasons in point number one and more that you don't need me to spell out.

3. The Whitecaps get disproportionately heavy-handed refereeing. This isn't as unlikely as it sounds. As a Canadian team, the Whitecaps get a larger share of Canadian Soccer Association referees, and it won't be controversial if I say they are less competent than their American counterparts.

   If CSA refs were a factor, we would expect to see Toronto FC and the Montreal Impact having the same problem. This doesn't quite happen. The Impact are sixth in fouls conceded and fifth in fouls suffered. Toronto is eighth in fouls conceded but eighteenth in fouls suffered. Toronto is the worst team in Major League Soccer and perhaps opponents don't need to foul them as much, but all other teams in the bottom five for fouls conceded are in the playoff hunt.

   Perhaps referees are biased against Toronto FC. Or perhaps this just isn't an adequate explanation.

4. Environmental factors. Prior to doing the math, this was my favourite theory. The artificial turf at BC Place, in my opinion and that of others I talk to, seems to be unusually slippery. More players just lose their footing in a half at BC Place than in two games elsewhere. You can imagine how players slipping around, falling over, accidentally clashing, etc. can lead to an increase in the number of fouls called.

   Unfortunately, I just can't prove it. More fouls are called at BC Place than on the road, but it's a minuscule number: there are an average of 29 fouls per Whitecaps road game and 29.71 fouls per Whitecaps home game. A .71 fouls per game adds up to 12.14 more fouls all season at home than on the road, or, statistically speaking, "diddly-squat". Take 12 fouls away from the Whitecaps and they're still right at the top of the league.

5. For lack of a better word, coincidence. There is no link between the high number of fouls the Whitecaps concede and the equally high number they suffer. They are a team which, for whatever reason, commits a lot of fouls, and for some completely different reason receives about as many.

I genuinely don't have a simple explanation. The data doesn't fully support any possibility I can think of except "coincidence", and that's always vaguely unsatisfying. You may want to take one possibility or another based on what you see in the games. But on the statistics I can't support any of them.

The data do not say that the Vancouver Whitecaps must be the dirtiest team in the league this year. But they certainly could be, and they must be dirtier than average.

[1] — Major League Soccer. "Statistics - Team Stats." MLSSoccer.com. Accessed September 25, 2012. http://www.mlssoccer.com/stats/team?sort=desc&order=FC.

[2] — Nevill, A.M., N.J. Balmer, A. Mark Williams. "The influence of crowd noise and experience upon refereeing decisions in football." Psychology of Sport and Exercise 3 (2002): 261-272.

[3] — Lane, Andrew M., Alan M. Nevill, Nahid S. Ahmad and Nigel Balmer. "Soccer referee decision-making: 'shall I blow the whistle?'" Journal of Sports Science and Medicine 5 (2006): 243-253.