Scatter graphics: Premier League, 21 Mar 2016
Ahead of the Easter weekend I thought it was a good time to update the scatter graphics for the Premier League, which compare the attacking and defensive performance of each club. These are explained here if you haven’t seen them before.
First of all, here is how the number of shots taken by each club compares with those they face in return. The average number of shots taken per match is on the horizontal and the average number faced is on the vertical, so bottom right (take plenty, allow few in return) is good while top left (take few, allow plenty) is bad. The stripes are like contours: the greener the stripe, the better the performance (and vice versa for red).
Their prospects of a top four finish continue to look slim but Liverpool are still dominating matches along with Man City and Tottenham. All three clubs, situated in the bottom right, have taken far more shots than they’ve faced this season.
Down in the bottom left, Man Utd have difficult to break down at the back but have offered less than most clubs going forward. The opposite can be said of fellow top four hopefuls West Ham in the top right, who may be taking an above-average number of shots but are also allowing their opponents plenty of opportunities.
The top left of the graphic shows that it’s not been an enjoyable season for fans in the North East, with both Newcastle and Sunderland spending most of their time on the back foot.
Now let’s look at attacking alone. The horizontal axis stays the same as in the graphic above, but now the vertical shows the average number of shots needed to score each league goal. Therefore bottom right is good (taking lots of shots and needing fewer efforts to convert) and top left is bad:
At the bottom of the graphic we can see that Everton and surprise leaders Leicester have been the most clinical, needing just over half as many shots as Villa to find the net on average.
Along with West Ham, they form a cluster of clubs who have finished well this season, while the likes of Tottenham and Man City have converted chances relatively averagely but created an impressive number of them.
Next let’s look at the defensive situation – basically take the above chart and replace the word “taken” for “faced” on both axes. Now top left is good – facing fewer shots and able to soak up more per goal conceded – and bottom right is bad:
Three of the five most restrictive defences have struggled to handle the shots that their opponents have managed to get away: Man City, Liverpool and (impressively) Bournemouth have all allowed few attempts at their goal but conceded readily from those that found a way through.
The other two – Man Utd and Tottenham – have fared far better, with Spurs operating the division’s most resilient defence: it’s taken almost twice as many shots to break them down than the Cherries.
West Ham‘s defence has soaked up plenty of punishment this season: they’ve allowed almost as many shots as Newcastle and Sunderland but have withstood almost five additional attempts per goal conceded.
Finally here’s an attempt at correcting the first graphic for the quality of chances created and allowed, using the same “expected goals” values that power my shot timelines (explained here). The reason for doing this is that the results tend to correlate more strongly with performance than when we treat all shots equally:
Leicester‘s defence looks relatively ordinary here, although their attack has been the fourth most productive. Their three main challengers for the title – Man City, Tottenham and Arsenal are wedged firmly in the bottom right, where one would normally expect to find all of the eventual top four.
Despite their disappointing seasons, both Chelsea and Liverpool‘s performances are still among the most impressive averaged over the whole campaign.
When we correct for chance quality like this we can see that Norwich jump up to join Sunderland and Newcastle in the worrying top left corner. All three clubs are in danger of relegation if things don’t improve (although it’s virtually impossible for all three can be relegated given the extent of Aston Villa‘s predicament).