Scatter graphics: Premier League, 2 Nov 2020

It feels like enough of the season has passed to justify a first 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).

As usual it’s Liverpool and Man City who are out-shooting the rest of the division. Games involving Aston Villa or Leeds have been pretty action-packed on average. Surprisingly Arsenal have been one of the quietest attacking teams while Brighton have allowed the fewest shots per match.

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:

It’s not been a great start for Sheffield United or Burnley, who are both creating a low number of chances and needing an average of almost 20 attempts to find the net. Leicester have actually taken fewer shots per match than the Clarets so far, but have been around five times as clinical, netting 17 times from just 65 shots (although their 6 penalties will be skewing this).

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:

Very few defences are having a good season so far, with Arsenal looking the healthiest at the back. Only Newcastle have soaked up more shots for each goal conceded, but the Magpies’ back line also is the division’s most permissive with almost 17 shots faced per match.

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, Man City and Tottenham have swapped places from the first chart, suggesting that Spurs have been better at getting shots away from dangerous positions. West Brom look to be in the most trouble, with the worst-performing attack and the third most open defence.