Scatter graphics: League 1, 7 Sep 2022
There have been just about enough matches played for a first outing of 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).
League leaders Ipswich are the most dominant team in the division so far, while Accrington have picked up from where they left off last season as the most shot-happy.
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:
Accrington may be out-shooting Ipswich but they’ve been much less clinical in front of goal. While Lincoln have been quiet going forward they’ve been fairly efficient at converting their chances.
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:
Morecambe are allowing a worryingly high number of shots so far, although they’ve been fairly competent at repelling them. The same can’t be said for Burton and Forest Green, who have seen their opponents’ efforts converted at a disturbingly high rate.
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 there is no standout team in the division at the moment: Ipswich are edging things overall and have the best attack, but Oxford look the most solid defensively. Morecambe‘s performances are some way adrift of the rest, which is concerning.