Scatter graphics: Premier League, 22 Dec 2020
Ahead of the festive fixtures it feels like enough time has passed to have another look at the scatter graphics. These compare the attacking and defensive performances of every team in a division – each of the four graphics is explained briefly below and at length here.
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).
Surprisingly Aston Villa have taken the most shots per match so far, edging out Manchester City and Liverpool. While Leeds aren’t far behind, they’ve also allowed their opponents to create more chances than all but three other sides. Brighton are a bit confusing as they currently sit 17th despite dominating overall in shot terms.
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:
Sheffield United and Burnley have both struggled to create chances and convert them, which isn’t a great combination. Arsenal also look significantly off the pace going forward, while Newcastle have compensated for a quiet attack with some ruthless finishing.
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:
Tottenham‘s defence has been allowing plenty of shots but they’ve been comfortably the best side in the division at repelling attempts on their goal. Brighton meanwhile are the leakiest team, meaning that the miserly amount of chances they’ve allowed their opponents to create hasn’t counted for much.
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:
When we adjust for shot quality, Chelsea look set for a strong season with the best-performing defence and one of the most potent attacks. Aston Villa are keeping up with the Blues and the division’s ‘big two’, while Brighton also have the potential to rise up the table. West Brom‘s change of manager looks less mysterious given how far off the pace they look here.