Scatter graphics: League 2, 4 Mar 2018
As we’re at the end of the calendar year and a shade over halfway through the season, 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).
While Luton are still looking comfortable at the top of the division and have handed out some spankings this season, they haven’t been the most dominant team overall. Wycombe are out-shooting them significantly and Cheltenham have also been pretty industrious going forward, while Coventry have allowed far fewer attempts at their goal.
Port Vale matches have been really quiet – only the aforementioned Sky Blues have allowed fewer shots but only three clubs have been less productive going forward.
Exeter may be in the play-off places but they’ve allowed the joint-most attempts at their goal along with Morecambe.
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:
Here’s where Luton‘s attack comes into its own: while it isn’t the most industrious, their strikers are by far the most clinical in the division. Interestingly the second-sharpest attack is Yeovil‘s, despite the Glovers taking the fewest shots in the division.
Grimsby‘s poor form owes a lot to their attacking performances: they’ve been the most wasteful team in front of goal and haven’t created much. Coventry have also struggled to convert their opportunities, which could end up costing them a play-off spot.
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:
Coventry look far better on the defensive side – in fact they’re streets ahead of the rest. While Port Vale have been almost as good at preventing chances, they’ve repelled the fewest per goal conceded of any club in the division.
Morecambe are once again soaking up a lot of shots – just as they did last season – but Exeter are performing genuine heroics at the back. I can’t remember a team getting promoted with that kind of defensive record, but there’s a first time for everything.
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:
Luton look a lot better when we adjust for shot quality, although Wycombe still narrowly edge them out in attack. Coventry and Lincoln both look far stronger in defence than attack but overall still look good enough for promotion.
Forest Green are some way off the rest of the division but they’ve closed the gap since the turn of the year. Barnet‘s defence is what’s put them in danger this season, while for fellow strugglers Chesterfield it’s the attack that’s been the bigger issue.