Scatter graphics: Premier League, 6 Nov 2019
As it’s been a month since the last batch, it feels worth updating 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).
Man City are unsurprisingly the most dominant side, with Chelsea and Liverpool vying to be their closest contenders. Interestingly things don’t look too bad here for winless Watford – they’ve taken and faced a similar amount of shots, but the next graphic will show where things are going wrong for them.
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:
Watford’s finishing has been horrific – it’s so bad that it should improve over time, as there’s almost certainly some bad luck contributing to that degree of underachievement. Southamton and Everton have been afflicted to a far less comical extent, while we can see that Leicester are the division’s most clinical finishers (no doubt boosted by that 9-0 result).
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:
Despite their horrible 9-0 defeat, Southampton’s defence haven’t been the leakiest overall. Everton have allowed marginally fewer shots for each goal they’ve conceded, although they’ve also permitted fewer attempts at their goal than anyone except Man City. Sheffield United’s impressive record is clearly visible here: not only are they soaking up more shots than anyone else for each goal conceded but it’s quite difficult to create chances against them in general.
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:
Correcting for shot quality shows that it’s attack where Man City are setting themselves apart. Chelsea also drop behind Liverpool and are closer to a Man Utd side that may not be quite as wobbly as feared. It’s interesting to see the three promoted sides all in different quadrants: Sheffield United look “safety first” while Aston Villa and Norwich have been kept busy at the back.