Scatter graphics: League 2, 3 Oct 2021
It feels like enough of the season has passed to justify a first look at 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).
Newly-promoted Sutton have taken the most shots so far, narrowly out-shooting Bradford. Leaders Forest Green join them as a trio of teams that stand out from the rest, although all three have been fairly open defensively. Colchester and Scunthorpe look to be spending a lot of time on the back foot.
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:
Forest Green‘s clinical finishing is matched only by Harrogate and Leyton Orient, with the latter having scored only two fewer goals despite taking over three fewer shots per match than the league leaders. Tranmere meanwhile have needed three times as many attempts as Orient to score each of their goals.
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:
I had to stretch the template for this one as Tranmere‘s ridiculous defensive record meant that all the other teams were squashed together at the bottom and I couldn’t fit all the labels in. Their first 10 games have seen just 10 goals in total, with only 4 conceded from over 140 shots faced and I’d be staggered if that doesn’t start to regress to something a bit more normal soon.
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 those three big-shooting teams from the first graphic lead the way again, with Forest Green deservedly top of the table so far with the best all-around performances. Colchester‘s defence looks worryingly open at the moment while Oldham look a bit toothless up front.