Scatter graphics: League 1, 31 Dec 2017
As we’re at the end of the calendar year and a shade over halfway through the season, here’s another update to the scatter graphics, which 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).
Wigan are still out on their own here: nobody creates more or allows less in return, with Peterborough and Portsmouth their nearest challengers at each end of the pitch respectively.
The trio of Gillingham, Northampton and Plymouth have looked the most troubled overall, with Fleetwood‘s quiet attack also a concern. It’s quite surprising to see Scunthorpe – currently in fourth place with a pretty healthy goal difference – in the top left quadrant.
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:
Poor Bury have really struggled in front of goal this season – despite creating a respectable amount of chances they’ve needed an average of 16 attempts to score each goal. There are seven clubs in the division who are more than twice as efficient, so you’d hope for the Shakers’ sake that their luck will change in 2018.
Fleetwood may not create much but they’re the division’s most clinical finishers – they’ve scored one more goal than Bristol Rovers despite taking five fewer shots per match.
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:
Four defences in particular have been unusually tough to break down so far: Shrewsbury, Scunthorpe, Wigan and Gillingham. The Gills are particularly interesting given the number of shots that they’ve had to deal with – more than anyone else in the division, while the Iron’s record helps to explain how they can be in promotion contention despite allowing an above-average number of efforts at their goal.
Oldham still aren’t out of relegation danger and their leaky defence remains a problem: nobody has soaked up fewer shots per goal conceded.
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 correct for shot quality Wigan look even more impressive: nobody is coming close to their level of performance at either end of the pitch. Blackburn and Rotherham look the next likeliest to prevail in the promotion race as things stand with strong numbers in both attack and defence.
Portsmouth and Doncaster have adapted well since returning to the third tier and both look credible play-off shouts, although they look stronger at the back than going forward.
Plymouth and Northampton look to be in the most trouble overall, but Gillingham‘s defence could see them dragged into a relegation battle. Bottom side Bury have actually been putting in some relatively decent performances overall, so if they can sort their finishing out then they could still scrabble towards safety.