“People who don’t understand football analyse with statistics”(1),
so said Jose Mourinho, 4 times world’s
best coach, 2 times champions league winner, 3 times English champion, 1 time
English FA cup winner, 4 time English league cup winner, 3 times Spanish
champion, 3 times Spanish cup winner, 2 times Spanish super cup winner, 2 times
Italian Champion, 1 time Italian Cup winner, 1 time Italian super cup winner, 2
times Portuguese champion, 2 times Portuguese cup winner, 1 time UEFA cup
winner, 1 time Europa League Winner, 1 time UEFA Super Cup winner, 2 times
Portuguese Super Cup Winner, 2 times English Super Cup winner (2)
On the other hand,
Pep Guardiola kind of referred to statistics when arguing that his team is not
dirty: “Normally when a team has 65 or 70 per cent of the ball we cannot kick
the opponent. We can kick each other, okay, but we have the ball. Normally when
for every 10 minutes you have the ball for seven of them there is less option
to make fouls. I don't think we're a team that make a lot of fouls in games.”(3).
So Mr Guardiola,
2 times world’s best coach, 2 times champions league winner, 1 time English
champion, 1 time English league cup winner, 3 times Spanish champion, 2 times
Spanish Cup winner, 3 times Spanish Super cup winner, 3 times German champion,
2 times German cup winner, 3 times FIFA club world cup winner, 3 times UEFA
super cup winner and 1 time English super cup winner (4) on the other hand,
uses statistics (sort of) when assessing his team.
And we have the
adage that my friend Ramesh reminded me of “Lies, Damn lies, and Statistics”
Given his past
record with respect to lies (5), let us consider the argument of Mr Guardiola.
Taking data from whoscored (6), I focused on the number of fouls committed per
game, and made a distinction between home games and away games.
In the chart
above, the teams who commit more fouls per game are on the exterior whereas
those who commit less fouls are closer to the origin. It is easy to see that Mr
Guardiola was right: Manchester City is one of the teams that make the least
fouls. It is an undeniable fact.
So is Mr
Mourinho wrong then?
This is where
context and subject matter expertise are important. I am very fond of the Drew
Conway data science diagram (), and it emphasises the need for subject matter
expertise.
What subject
matter expertise would you ask?
Well, enough to
understand that Manchester City play a possession based strategy, basically
they keep the ball for huge chunk of each game. This element provides context.
This is football
(or as Americans call is soccer) and players are not allowed to tackle players
who do not have the ball, basically your opponents are much more likely to try
and attack you when you have the ball; when you do not have the ball, you are
unlikely to be attacked. The more time the ball spends in your possession, the
less likely you are to commit a foul.
Hence, what
matters is not fouls per game, but fouls per number of minutes the opposition
has the ball.
Now the
situation looks totally different doesn’t it. Manchester City is not among the
teams that commit fewer fouls per minute out of possession; they commit more
than their fair share of fouls when the opposition has the ball; in fact, if
you look only at home games, they commit the most fouls adjusted to possession
than any other team in the premier league.
Also
interestingly, Chelsea and Liverpool also foul consistently. It makes sense, if
your tactics are around overloading opponents, it makes sense that if the
opponent gets the ball (by passing your press), you would be very overloaded
too, hence the tactical foul to allow you to regroup and balance the situation.
In fact, that
was what Gary Neville was referring to when he said that Manchester City is a
cynical team (and that he likes that).
Actually what I
find interesting is the fact that Manchester City’s triangle is very asymmetric.
They foul much more at home than away. They are much more aggressive at home,
having scored twice as many goals as they have away; Chelsea and Liverpool are
much more balanced.
Anyway I can
happily disagree with Mr Guardiola, after all you wouldn’t expect a coach to
agree that he asks his players to commit fouls, but I would have expected him
to keep quiet rather than manipulate the data in his favour. I thought the
temple of “fake news” is located at the white house., apparently it has a
branch at the Etihad (and I am not commenting on the FFP and other allegations
by Der Spiegel (7) such as “We do what we want”)
Was this a case
of “Lies, Damn Lies, and Statistics”? “Fake news” yes, deliberate
misdirection/white lying may be, but it’s not the fault of statistics, it’s the
fault of the person who chose the metric (number of fouls per game rather than
number of fouls adjusted for possession) rather than the metric itself.
So was it an
illustration of what Mr Mourinho was saying, that “people who do not understand
football analyse with statistics”?
Well, since I am
currently spending a lot of my energy trying to make an organisation increase
its adoption and usage of statistics in decision making (not a football club
though, any takers?), I would neither agree or disagree, and hide, as usual
behind “it depends”.
It depends on
what Mr Mourinho actually meant. Saying the people who do not understand
football analyse with statistics is not the same as saying that people who
understand football do not analyse with statistics. Please note that since we are dealing with absolutes, the intersections will be shown as changes in colour of the affected regions (for example red overlap with yellow makes orange, and red with blue makes purple)
The world is
made up of people who understand football and those who don’t.
Now let’s add
people to analyse football with statistics, Jose Mourinho’s words can be seen
as:
There is a
perfect overlap between people who do not understand football, and those who
use statistics to analyse football.
But his
statement is equally valid if:
In this case
there are people who understand football and do use statistics to analyse it;
presumably Mr Mourinho has at least one such analyst in his team.
So what am I
saying?
I deliberately
started this blog with a seemingly controversial statement by Mr Mourinho, who
is someone with many detractors. It is possible that a proportion of people
would have interpreted his words as the orange and blue diagram above, just
because of what they perceive Mr Mourinho to be, that is negatively. Hence they
may not have seen his statement as representing the last diagram above, which is
not very controversial.
On the other
hand, if you just go on a search engine and look for Guardiola and Gary
Neville, you will find many more articles on the response of Mr Guardiola, than
on the statement by Mr Neville. Again, Mr Guardiola has a better image and
people tend not to analyse his statements as critically, whereas Mr Neville can
be polarising, hence the focus on the rebuttal of his statement.
But as you can
see, at least in this case, Mr Guardiola was dealing in “fake news”.
Conclusion(s)
While the source
of any data should be looked at, personal feelings towards the person
delivering the message should not get into the picture. Data is data and should
be analysed without prejudice
That being said,
if the person who does the analysis has “mis-spoken” frequently in the past,
then it makes sense to review their data a little bit closer, after all
frequency of mis-speaking is a characteristic…
One of the
simplest ways of analysing data is to put it in a proper context, and this
takes some understanding of the data, the process of data creation, some
subject matter expertise, and an open but critical mind.
P.S. While I
wrote this blog last week, this weekend, Chelsea played and beat Manchester
city. In total Chelsea committed 12 fouls, Manchester City 11, whereas
possession was 39%-61%; hence Chelsea made more possession adjusted fouls than
Manchester City. Chelsea won, by the way and disrupted Manchester City,
restricting them to only 4 shots on target, their average being 6.1.
- Pep Guardiola’s changing defense against his convictions for taking performance enhancing drugs, and the power of unstable urine in all 4 tests as proposed by his still close collaborator, Mr Manuel Estiarte http://www.sportingintelligence.com/2017/04/25/sharapova-guardiola-doping-darkness-and-light-250401/
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