Scatter graphics: Championship, 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.
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 have the healthiest balance between shots taken and faced so far, while West Brom have seemed as potent in attack but at the expense of defensive solidity. Sheffield Wednesday have looked the most open at the back, while the lack of chances created by Ipswich and Bolton are concerning.
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:
West Brom have been scoring for fun this season – not only have the Baggies created plenty of chances but they’ve also been the sharpest finishers by a decent margin. Both Middlesbrough and Bristol City have fared far worse from a similar number of chances, having needed around two more shots than the average team to find the net.
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:
Middlesbrough’s attack may have been a bit wasteful, but they’ve made it incredibly difficult for opponents to score against them. They’re pretty much wrecking this graphic, having soaked up over 25 shots for each goal conceded when the average for the division is around 10, and making the impressively stubborn Swansea defence look relatively ordinary. Preston, Millwall and Ipswich have all been frustratingly leaky at the back despite allowing a relatively respectable number of chances.
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 Sheffield United to come out as the best all-round performers, although the strong defences of Leeds and Middlesbrough are keeping them in touch. Ipswich and Bolton badly need some additional guile up front, while Reading and Sheffield Wednesday’s problems are mainly at the back. Defence is also an area where West Brom could improve if they’re to sustain a promotion challenge.