Scatter graphics: League 2, 1 Nov 2020

It feels like enough of the season has passed to justify a first look at 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.

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).

Carlisle‘s squad overhaul looks to have paid dividends as they – along with Forest Green and Newport – form a dominant trio of clubs who are all creating far more chances than they’re allowing. Meanwhile Southend and Colchester look like they could find themselves in trouble, with the former struggling to get shots away and the latter unable to stop them raining in.

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:

Stevenage‘s horrible record in front of goal is stretching the chart for the second season running – despite creating a respectable number of chances they’ve had very little luck at converting them. Carlisle and Forest Green may be outshooting most teams but they’ve also not found the net as reliably as the average team.

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:

Salford‘s defence – or at least their goalkeeper – has been working hard to repel an above-average number of shots. Struggling Scunthorpe have faced slightly fewer per match but have conceded at more than three times the rate. Colchester can also thank their back line for keeping them competitive, just as their sharp finishing has made the most of their relatively few chances at the other end.

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:

When we adjust for shot quality, it looks like the current bottom two of Scunthorpe and Southend haven’t been unlucky so far. Likewise the current top three of Newport, Cambridge and Cheltenham have all been performing well and I’d expect Forest Green – who’ve improved hugely since last season – to challenge for automatic promotion if they can sustain their current levels.