Scatter graphics: League 1, 1 Nov 2020
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).
It’s strange to see that league leaders Peterborough have taken and faced almost identical numbers of shots per match to bottom side Oxford – even if the latter were to win their two games in hand they’d still be underachieving in mid-table. MK Dons also stand out as an underachiever given that they’ve faced the fewest shots but have earned less than one point per match.
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:
Shrewsbury‘s wasteful finishing is costing them so far – they’ve needed almost twice as many attempts to find the net as the average side, despite creating a respectable number of chances. The gap between the almost equally productive attacks of Oxford and Peterborough can also be explained by the former being almost twice as profligate 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:
Charlton have conceded just five goals so far despite facing an above-average number of shots, with over 20 attempts allowed for each time they’ve conceded. While MK Dons have faced around five fewer attempts per match, they’ve been breached roughly four times as easily.
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 chance quality, Wigan look to be in the most trouble so far, although Gillingham‘s defence could do with some improvement and Charlton may find their attack running out of steam. Sunderland and Portsmouth currently sit on the fringes of the play-offs but I wouldn’t be surprised to see them claw their way upwards as the season unfolds.