Scatter graphics: Championship, 4 Feb 2019
I realised over the weekend that it’s been a fair while since I updated 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).
In raw shot terms, Leeds have been the divison’s most dominant side, with Brentford still looking good overall despite their rollercoaster season. Ipswich and Bolton look to be in the most trouble here, while matches never seem to be boring when West Brom are involved.
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:
The size of the gulf between Bolton, Ipswich and the rest of the division is pretty depressing for fans of those two clubs: they create far fewer chances than anyone else and haven’t exactly been clinical when presented with opportunities. Rotherham have had similar frustrations in front of goal despite at least firing in a decent number of shots.
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 remain a case study in resilience, having soaked up almost twice as many shots for each goal conceded as the average team in the division. Bristol City also deserve a mention for being tough to breach, while Millwall and Brentford have conceded frustratingly often given how few opportunities they usually allow their opponents.
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 – at least as well as I can measure it – then Sheffield United look to be giving Leeds a run for their money, so we could be in for a dramatic promotion race. West Brom and Aston Villa have looked excellent going forward but relatively average at the back, which could end up costing them both promotion if not addressed. Things don’t look any healthier for Ipswich or Bolton here, and Reading – who rank worse than either defensively – are also in a spot of trouble if something doesn’t change.