Scatter graphics: League 1, 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).
Peterborough’s position near the top of League 1 is one of the more confusing features of this season so far, given the unhealthy balance between the shots they’ve taken and faced. In the opposite corner of the graphic, Barnsley’s electrifying start has continued and they’re still creating around twice as many chances as their opponents.
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:
Wimbledon’s finishing looks to have cost Neal Ardley his job, with his side having required around twice as many shots as the average team to find the net. Bristol Rovers and Shrewsbury have also endured some frustration in front of goal despite creating a respectable amount of chances, while we can see that both Sunderland and Peterborough owe their impressive goal tallies to some incredibly precise finishing.
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:
Not only are Sunderland and Peterborough looking incredibly sharp up front but they’ve made it difficult for opponents to get the ball in their net. Bristol Rovers’ miserliness at the back is mirroring their troubles up front, with the result that only 14 goals have gone in at each end during their 17 league games so far.
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:
Barnsley don’t lead they way by quite as much once we adjust for shot quality, suggesting that a fair proportion of their shots are from long range. Fleetwood and Oxford look as though goalscoring could be a problem at some point this season, having posed noticeably less of a threat than the rest of the division, while Walsall’s recent poor form isn’t all that surprising given their worrying position here.