Scatter graphics: League 1, 10 FEB 2021

Seeing as I last ran them in December it feels like enough time has passed to have another 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.

Shot dominance

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).

Sunderland have looked the most dominant in shot terms, so it’s strange to see them outside the top six at the moment. Leaders Lincoln meanwhile are making their relatively modest balance of chances count. Accrington are out-shooting the rest of the division but also allowing plenty of efforts at their own goal.

Attacking effectiveness

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:

Northampton and Bristol Rovers have really struggled to convert their chances so it’s no surprise to see both clubs opting to change managers. Meanwhile Doncaster have been ruthless, needing an average of just 7 attempts to find the net.

Defensive effectiveness

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:

Leaders Lincoln have been the toughest side to break down this season, facing more than twice as many shots per goal conceded as the leakiest defences like those of Swindon and Burton.

Expected goals

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, Sunderland still look to be underachieving. Their performances have been on a par with the actual top two of Lincoln and Hull, who appear to be there on merit.