Scatter graphics: League 1, 26 Nov 2017
Here’s another update to the scatter graphics, which 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).
Wigan continue to be the most dominant team in the division by far, with only Peterborough taking more shots per match and nobody allowing fewer in return. Doncaster and Portsmouth come the closest in terms of defensive solidity, although both have struggled to pair that with a consistent attacking threat.
Three of the current bottom four – Plymouth, Gillingham and Northampton – are lodged in the undesirable top left corner, while Bury are a bit more confusing as they haven’t looked all that bad overall.
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:
Bury‘s problems look clearer here as they’ve struggled to convert their chances to a similar extent as their fellow relegation battlers, even though they’re creating more on average. In fact the current bottom five are the five most wasteful finishers in the division.
Fleetwood have created the fewest goalscoring opportunities of all but have been impressively ruthless at finding the net. Nobody has taken fewer shots per goal scored and they’ve been twice as efficient as the bottom five.
Blackburn were expected to dominate the division this year, but they’ve been relying on quality over quantity as we can see here and in the next chart below.
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:
Scunthorpe, Shrewsbury and Blackburn have all soaked up an impressive number of chances for each goal conceded, while Gillingham would be in a worse predicament still if the huge number of shots they’ve been allowing were going in at an average rate.
Oldham‘s problems – at least prior to their revival – seem to be mostly in defence, where they’ve leaked goals at a worrying rate. Only Bristol Rovers have conceded more readily, while Fleetwood‘s opponents have been finding the next almost as easily as their own attackers.
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 correct for chance quality Wigan look even more impressive, with their attack creating more than twice what they’ve allowed their opponents to carve out. Nobody else comes close at the moment.
Bradford are confusing me this season. They’re sitting fourth in the table, which is pretty consistent with what I would have expected based on last season’s impressive performances, except their data looks really average so far.
MK Dons are having an awful season and could easily be sitting in the bottom four at the moment. With only a four-point cushion and several teams below them – Bury and Wimbledon in particular – looking capable of climbing the table, there’s plenty to be worried about.