Scatter graphics: League 2, 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).
The trio of Bury, Forest Green and Mansfield look to be the most dominant in the division, while Cambridge would be among them if they could tighten up a bit at the back. Grimsby look to be spending a lot of time on the back foot, having allowed over six shots per match more than they’ve taken.
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:
Both Grimsby and Cambridge stand out for the profligacy of their attacks so far: they’re each requiring an average of around 15 shots to score each goal, which is almost six more than the league average. Meanwhile both Exeter and Lincoln have been banging in the goals despite taking relatively few shots – along with Colchester, these two have been the most clinical finishers in the division by 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:
MK Dons are absolutely wrecking this graphic with some incredibly stubborn defending. I’ve watched them play this season and their defence did a great job of closing down shots, so if they’ve kept this up then that could explain their position here. While Crewe and Grimsby have faced plenty of attempts at their goal, they’ve also been adept at soaking them up.
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 Bury and MK Dons who now stand out as the strongest-looking sides in the division. Notice how Cambridge are bang in the middle compared to the first chart, suggesting that a lot of the shots they’re taking are probably low quality efforts. Northampton’s rise up the table hasn’t been surprising given how strong their attack has looked, and unfortunately it wasn’t a shock that Grimsby’s run of good form last month was relatively short-lived. Some lacklustre attacking performances look to have done for Phil Brown at Swindon, while Carlisle are another side whose dip in form was predictable from the underlying data.