Scatter graphics: Championship, 27 Dec 2019
As we’re roughly at the halfway stage of the season, 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).
Leeds continue to set the standard at both ends of the pitch, with the most shots taken and the fewest faced. Brentford are their closest challengers and Sheffield Wednesday are also looking pretty dominant overall. Charlton and Luton have found the return to this level tough going, as have Huddersfield (more surprisingly seeing as they arrived from the opposite direction).
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:
Here we can see why Leeds aren’t running away with the title: for all that shooting they’ve struggled to find the net regularly. Leaders West Brom have taken over three fewer shots per match but have 10 more goals to their name thanks to one of the most ruthless attacks in the division. Both Charlton and Bristol City can thank their clinical forwards for converting a below-average number of chances into an above-average number of goals.
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:
While the Leeds attack has some questions to answer, there’s no arguing with that defensive performance: not only the fewest shots allowed but also the most faced per goal conceded. Nottingham Forest are almost as resilient despite allowing opponents far more opportunities. Stoke, QPR and Barnsley meanwhile have all been let down by leaky defences despite doing good job of restricting the number of chances their opponents get.
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, it’s still Leeds who are out in front: nobody cones close in attacking terms but Brentford look almost as robust at the back. Sheffield Wednesday look pretty good at both ends of the pitch and it’s no surprise to see Stoke gradually climbing the table given their decent underlying performances. Huddersfield’s attack is still far too quiet so perhaps they’ll be looking for reinforcements in January.