Scatter graphics: League 1, 2 Mar 2016
Here are updated scatter graphics for League 1, which compare the attacking and defensive performance of each club. These are explained here if you haven’t seen them before.
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).
The top corners of the graphic are home to the division’s main outliers. Starting in the top left, Crewe have taken the fewest shots and allowed more than anyone else in return – marginally more than Blackpool – so remain in real danger of dropping into League 2.
In the top right we have the ongoing entertainment of Peterborough, who are massively out-shooting the rest of the division but at the expense of allowing plenty of shots at their own goal.
It looks like someone’s swapped Colchester and Southend around: the former are struggling in the relegation zone despite seemingly dominating matches while the latter remain in the play-off hunt despite regularly allowing more shots than they take.
Barnsley spent Christmas in the relegation zone but are now on the outskirts of the play-offs, with their overall dominance of matches this season second only to leaders Burton.
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:
Strangely most of the teams fall into one of two clusters – a wasteful layer across the top of the chart and a more clinical one in the lower left. A few prolific shooters like Peterborough, Coventry and Walsall form a breakaway third group in the top right.
Two promotion-chasing sides – Gillingham and Millwall have converted their chances at an impressive rate despite taking a relatively average number of shots.
Leaders Burton remain one of the most wasteful finishers, which could yet cost them the title if the likes of Wigan and the aforementioned Gills continue to be more efficient in front of goal.
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:
Burton‘s attack may not be the sharpest but not much gets past their defence. Along with promotion rivals Wigan the Brewers have allowed few shots and soaked up plenty of those that do get through.
At the bottom we can see the main reason for Colchester‘s struggles: their defence remains shockingly easy to breach. Withstanding around four shots for each goal conceded is incredibly bad and I genuinely can’t see them staying up at this rate.
While Blackpool have allowed plenty of attempts at their goal, they’ve repelled an impressive proportion of them. Southend have also got their defence to thank for soaking up lots of punishment.
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:
Blackpool look a lot less doomed when we correct for chance quality, but Crewe remain lodged in the extreme top left of the “bad quadrant” and it will take something special for them to pull away from the drop zone.
Despite their calamitous recent form, Peterborough remain the most dangerous side going forward (at least when performances are averaged over the whole season) but also a danger to themselves at the back.
In the bottom right Burton remain the strongest all-round performers, with the chasing pack arranged into two clusters: one containing teams strong at the back but average up front and the other vice versa.