Scatter graphics: League 2, 10 Dec 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).
Bury are comfortably the most dominant side in raw shot terms, with Mansfield and Forest Green their nearest challengers. It’s not been a good season so far for black-and-white striped teams, with Notts County and Grimsby on the back foot most often.
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:
Macclesfield and Cambridge are both struggling this season and their finishing has been one of their biggest shortcomings: both have needed an average of over 14 attempts to find the back of the net in a division where the average is five fewer. Lincoln meanwhile have built their promotion challenge on some incredibly sharp shooting, taking only six shots for each goal scored so far.
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 Imps’ title rivals MK Dons are excelling at the other end, having soaked up almost 20 shots for each goal they’ve conceded, which is more than double the average for the division this season. Newport meanwhile have only been able to repel between six and seven for each time the ball’s ended up in their net.
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, Bury‘s edge that we saw in the first graphic is eroded almost completely. MK Dons and Mansfield are putting in similarly impressive performances, with Lincoln not far behind. Northampton‘s recovery from a poor start doesn’t surprise me given how good they’ve looked in the underlying data.
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