Here's another analysis of shot creation in the Premier League. This time, I'm looking into the creation of accurate shots from one specific kind of situation: open play.
From the earlier analyses, we already know the following basic facts from the first half of this year's EPL season, based on data from the Opta/Guardian chalkboards. First, shots from open play are by far the most common type of shot created; about 75% of all shots teams created came from this source. On average, Premier League teams each create about 4.4 accurate shots on goal per match total, and about 3.4 accurate shots from open play.
As always, these averages can easily disguise differences across teams. So here are accurate shot creation statistics from open play separately by team.
Turns out, there was quite a variety in the numbers of accurate shots created from open play, ranging between roughly 2.5 and 5 accurate shots per team and match. Arsenal led the league in the first half of the season in accurate shots created from open play, followed by Chelsea and Manchester United. Surprisingly strong in this category were Wolves and Everton. A the low end, Birmingham, Blackburn, West Ham, Sunderland, Stoke, and West Brom all managed fewer than 3.
But the stats for Wolves, for example, also lead to the next logical question: knowing how many shots teams created from any one match situation is one thing. After all, Wolves have not been doing all that well this year. So is this because they were not particularly efficient in generating accurate shots? That is, how does the number of accurate shots related to the overall shots teams created?
To get a sense of this, it's best to look at proportions or ratios. So here are the ratios of accurate shots relative to all shots created from open play.
Recall that the overall average ratio of all accurate to all shots is .3, and that shots created from open play were right around the average in accuracy. One way to think about these ratios is that they tell us how efficient or profligate teams were with the chances they did create from different match situations. So having a high accuracy/overall shots ratio tell us that a high percentage of shots a team created from open play found the target.
Here's how teams stacked up halfway through the season on this score.
From the earlier analyses, we already know the following basic facts from the first half of this year's EPL season, based on data from the Opta/Guardian chalkboards. First, shots from open play are by far the most common type of shot created; about 75% of all shots teams created came from this source. On average, Premier League teams each create about 4.4 accurate shots on goal per match total, and about 3.4 accurate shots from open play.
As always, these averages can easily disguise differences across teams. So here are accurate shot creation statistics from open play separately by team.
Turns out, there was quite a variety in the numbers of accurate shots created from open play, ranging between roughly 2.5 and 5 accurate shots per team and match. Arsenal led the league in the first half of the season in accurate shots created from open play, followed by Chelsea and Manchester United. Surprisingly strong in this category were Wolves and Everton. A the low end, Birmingham, Blackburn, West Ham, Sunderland, Stoke, and West Brom all managed fewer than 3.
But the stats for Wolves, for example, also lead to the next logical question: knowing how many shots teams created from any one match situation is one thing. After all, Wolves have not been doing all that well this year. So is this because they were not particularly efficient in generating accurate shots? That is, how does the number of accurate shots related to the overall shots teams created?
To get a sense of this, it's best to look at proportions or ratios. So here are the ratios of accurate shots relative to all shots created from open play.
Recall that the overall average ratio of all accurate to all shots is .3, and that shots created from open play were right around the average in accuracy. One way to think about these ratios is that they tell us how efficient or profligate teams were with the chances they did create from different match situations. So having a high accuracy/overall shots ratio tell us that a high percentage of shots a team created from open play found the target.
Here's how teams stacked up halfway through the season on this score.
One thing that pops out is that Arsenal had a higher efficiency in creating accurate shots from open play than Chelsea and the Manchester clubs, and did notably better than Tottenham and Liverpool. As well, Wolves actually were among the best teams in the league in creating high percentages of accurate shots from open play situations. A couple of surprises: Bolton and Newcastle. The Trotters and Magpies didn't create all that many accurate shots from open play, but these shots were significantly more likely to be on target than those of other clubs (save Arsenal). On the flipside, Everton's ranking on efficiency is lower than its ranking on shots created. While the Toffees were among the league leaders in creating chances from open play (only Arsenal created more), their shots found the target less frequently.
So how do frequency and accuracy of shots combine to create particular profiles of open shot creation for different teams? An easy way to look at this is to graph them against each other. Teams want to be in the upper right hand corner - create lots of shots an make them accurate - and avoid the lower left hand corner, where teams that don't create many shots and that create few accurate shots reside.
Some obvious patterns: league leaders Arsenal, Chelsea, and Manchester United clustered together in the upper right hand corner. In contrast, Blackburn and in particular Birmingham just weren't creating shots from open play, and the ones they did create were not all that accurate. As well, Everton was up there with the big clubs in creating chances from open play, but their accuracy numbers were relatively lower. Among the teams that were creating few chances from open play, Wolves stood out in making them accurate. Most of the other clubs clustered around the league median (denoted by the red lines); most teams created between 10-12 shots from open play, of which 3-3.5 tended to be accurate.
If you've managed to read up to this point, these patterns may raise as many questions in your mind as they answer. For example, I'm sure supporters of different clubs will see patterns I haven't picked out, and I welcome you to note them in the comments section. As well, these descriptions say nothing about tactical reasons for the patterns we see; naturally, some of them are intentional in that teams aim to do one thing over another in a match - create chances from open play v. fast breaks, for example - and absent systematic information about this, we have to guess. And, it is of course not clear if the patterns described here have held in the second half of the season as managers have adjusted to teams' successes and failures.
Of course, as I've pointed out before, while shots created from open play are more likely to be accurate than shots from dead ball situations, they also have a lower chance of being accurate than shots from transition play. I look forward to tackling differences in teams' shot profiles from other match situations soon.
