Scatter graphics: Premier League, 10 Feb 2021

Seeing as I last ran them in December 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.

Shot dominance

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).

The big two of Liverpool and Manchester City have re-established their shot dominance, with Chelsea their closest challengers despite some mixed results. Leeds and Aston Villa have looked impressive in attack but less so in defence, while West Brom look to have spent the most time on the back foot having allowed more than twice as many shots as they’ve taken.

Attacking effectiveness

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. Fulham are the only side with a worse shot conversion rate, which undermines a respectable number of chances created for a newly-promoted side. Everton have been the most clinical finishers, edging out a Tottenham side who have also taken a below-average number of shots so far.

Defensive effectiveness

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 the best side in the division at repelling attempts on their goal. Manchester City are setting the standard at the moment, with the fewest shots allowed and one of the best records at soaking up attempts on their goal. Southampton‘s recent heavy defeat means their defence is now the division’s leakiest, just ahead of Liverpool for fewest shots faced per goal conceded.

Expected goals

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 are on a par with Liverpool in Manchester City‘s wake. Brighton are the surprising name amongst the chasing pack here, with their results falling short of their performances overall this season. Sam Allardyce has his work cut out at West Brom given how far they are off the pace at both ends of the pitch.