Scatter graphics: League 2, 8 Oct 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.

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).

Coventry are the most dominant side overall – and by quite a distance – taking just under 14 shots per match and allowing fewer than half as many in return.

There’s no one team that stands out as the least dominant, although Yeovil are creating worryingly few chances and Morecambe are once again allowing plenty, with Crewe also giving their fans plenty to be concerned about.

Newport continue to create the most chances in the division, although their defence has looked far more average. At the other end of that spectrum we have Port Vale, who allow relatively few chances but don’t create much themselves.

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:

I was wondering how Notts County were sustaining a promotion challenge off the back of such a modest number of chances and here’s at least part of the answer: only Yeovil have converted shots into goals more efficiently so far.

Kevin Nolan’s side are outscoring Coventry and Newport despite taking around five fewer shots per match due to the wasteful finishing exhibited by the Sky Blues in particular.

However there are bigger problems at both Chesterfield and Morecambe, who create a respectable number of chances but have needed around five more attempts than the average League 2 side – and over twice as many as a similarly productive Accrington – 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:

Coventry‘s defence has looked impressive from the beginning – they’ve allowed far fewer shots than anyone else and are also one of the division’s most resilient at soaking up their opponents’ efforts.

While Wycombe have looked impressive up front (see last chart) and are the division’s top scorers, a defence as leaky as struggling Port Vale‘s has kept their goal difference relatively modest.

Exeter‘s stubborn defence has sustained their promotion charge so far and they’ve absorbed more shots per goal conceded than anyone else, although fellow challengers Stevenage and Newport aren’t far behind.

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:

While Coventry have looked the most impressive overall, their attack has looked pretty average compared to that incredible defence, so it remains to be seen whether they can score enough goals to see their dominance pay off.

While few will be surprised to see pre-season favourites Mansfield and Luton looking healthy, they have plenty of company in Cheltenham, Wycombe and Lincoln in the desirable bottom right quadrant. All three look capable of at least a play-off finish as it stands.

Crewe and Forest Green look to be in the most trouble overall, so while the former’s league position looks relatively healthy there’s a chance that they’ll stall if performances don’t improve.

An honourable mention should go to Harry Kewell at Crawley, who has defied pre-season expectations of a relegation battle with some solid overall performances (cue collapse in form and him being sacked before Christmas).