Scatter graphics: Premier League, 12 Nov 2018

With a few managers losing their jobs today and the combination of an FA Cup round and some international fixtures thinning out the domestic fixture list, it felt like a good time to refresh 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 Premier League picture is definitely more stretched out than for any of the EFL divisions, with Manchester City creating almost three times as many shots as they allow while Burnley are doing the opposite. Chelsea look to be City’s closest challengers in raw shot dominance terms, while Brighton have looked worryingly vulnerable despite sitting in mid-table. Wolves deserve a mention for how comfortably they’re adapting to life back in the top flight.

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:

Arsenal’s forwards have been lethal this season – despite the Gunners creating a relatively average number of chances, nobody’s been more clinical at turning shots into goals. Huddersfield and Southampton meanwhile have struggled to find the net, needing over twice as many attempts as the average team to do so.

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:

Brighton have been able to soak up a lot of the shots they’ve allowed so far, but it’s not clear if they can keep this up. Cardiff and Fulham are struggling to adjust to the top flight by the looks, with both only facing around six shots for each goal conceded. In recent seasons Liverpool spent much of their time in the bottom left of this graphic, but their defensive upgrades now see them ranking as one of the most stubborn rearguards this time around.

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, Burnley, Fulham and Brighton stand out as the most worrying teams – particularly in defence where they’ve allowed opponents far better opportunities than anyone else. Liverpool and Chelsea sitting in second and third appears just, as they look the best equipped to give Manchester City a run for their money on this evidence.