Scatter graphics: League 1, 5 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).
Bolton are still a worrying outlier after their awful start, but their record is improving: for the first time this season I’ve not had to stretch any of these charts to fit them in. Doncaster are shooting with abandon so far, having racked up almost five more attempts per game than the average side.
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:
Peterborough and Oxford have looked formidable going forward this season, creating plenty of chances and converting them more ruthlessly than anyone else. Accrington meanwhile stand out among a clutch of teams who have gotten the quantity aspect of attacking right but are struggling to match it with quality.
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:
The current bottom three all look a bit cast adrift here: Southend aren’t allowing quite as many shots as MK Dons but they’ve struggled to keep opponents out. The top two of Ipswich and Wycombe have been difficult to break down, with the Tractor Boys in particular making it tough to even trouble their goalkeeper.
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, we can see that Southend are in real trouble: their record is similar to a Bolton side who had to field a skeleton squad at the start of the campaign. The trio of Wimbledon, Rochdale and MK Dons form an island of other poor performers who are in the most danger of filling out the relegation zone. There’s no clear stand-out team at the moment, but it’s fair to say that Portsmouth look far too good to be sitting in the bottom half.