In the last week or so I have been tweaking my Premier League database in order to make it easier to query and so it is, generally, well, more ordered. Part of the tweaking involved arranging the numbers in home and away categories. Why would I want that? Well, so I can do things like this:
Shots On Target +/- (2011/12 to 2013/14)
This table shows every Premier League team from that span and their home and away shots on target +/-. It also shows their Overall shots on target +/-.
It is an interesting table, we can easily compare the same team over 3 seasons and chart their progression or regression. We can see which teams have been historically bad. We can also see how big the margin is between the average shots on target +/- for home teams and away teams.
This table is sortable and scrape-able. So sort and scrape it.
|SoT Away||Home +/-||Away +/-||Total +/-|
|Man City 11/12||4.5||1.7||6.2|
|Man City 12/13||3.1||3||6.1|
|Man City 13/14||3.6||2||5.6|
|Man Utd 11/12||3.7||0.9||4.6|
|Man Utd 12/13||2.9||0.5||3.4|
|Man Utd 13/14||2||-0.4||1.6|
|West Brom 11/12||0.4||-0.6||-0.2|
|Aston Villa 13/14||-0.6||-0.2||-0.8|
|West brom 12/13||0.9||-1.8||-0.9|
|West Brom 13/14||0.3||-1.7||-1.4|
|Aston Villa 11/12||-0.2||-1.7||-1.9|
|Aston Villa 12/13||-0.3||-2.3||-2.6|
|West Ham 12/13||0.1||-3.3||-3.2|
|West Ham 13/14||-1.7||-2.8||-4.5|
The table is set to Overall shots on target +/-.
Man City occupy 3 of the top 6 slots.
At the bottom, Reading and Wolves were relegated. Cardiff, Fulham and West Ham may well join those poor teams.
Home Shots On Target +/-
Some very dominant home teams and a few terrible home teams.
The sharp eyes will have notice the average number for home shots on target is +0.945. This is the average number of shots the home team will outshoot the away team by.
Or, if you prefer those numbers in percentage form:
Some truly dominant teams may well skew that average, there may well be some score effects at play too.
Man City top the chart with +4.5 Shots on target per game in 11/12. It's a big margin, and it goes a long way in explaining their sensational home form in that season. City may well better that number this year with an easy run of home games coming up,
Away Shots On Target +/-
Away disadvantage is -0.945 shots on target per game.
The spread of teams isn't as wide here as it is for home shots on target. City posted the best season in 12/13 (my records, at least) but were crippled by a PDO of 88.98.
Now, there are terrible teams in every league. But every now and then, a really special case comes along. Fulham, step right up. Through 11 away games Fulham are -59 shots on target away from home. It is such a filthy number.
The chart above best illustrates Fulham's ineptitude on the road. I had to change the scale of the graph to accommodate such performance.
The short of it is this:
- There is a wider spread of performance between the home teams than there is among the away teams.
- Home advantage is +0.945 shots on target per game.
- Once we know this, we can create home/road adjusted SoTR's.
- That home/away tilt is roughly 55% to the home team, 45% to the away team.