It’s been roughly a month since the last set was produced so I’ve updated the scatter graphics, each of which 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).

Portsmouth continue to be the most dominant team in the division – taking the most shots and allowing the fewest – so it’d be a surprise not to see them continue pushing for a top three finish.

None of the three current incumbents can match Pompey’s consistency here: leaders Doncaster are great at stopping opponents from shooting but create a relatively average amount themselves, second-placed Plymouth are almost slap bang in the middle and Carlisle shoot often but also allow plenty of efforts in return.

The real puzzle is Accrington, who have been consistently dominant yet remain lodged at the wrong end of the table. The next chart in particular will shed some light on this.

At the top of the graphic, Morecambe‘s defence still looks worryingly permissive, but at least they’re creating a decent number of chances 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:

Let’s start at the top, where Accrington‘s problems are laid bare: they’ve needed around five more attempts than the average side to score each league goal this season, so taking the third highest number of shots hasn’t been much help to them.

Doncaster‘s table-topping owes plenty to their attack being the division’s most clinical: with 5.5 shots taken per goal scored they’re comfortably more than twice as efficient as Stanley despite creating around two fewer shots per game.

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:

Doncaster‘s attack may be the division’s most efficient at converting chances but their defence has been its leakiest. The good news is that only Portsmouth – who are also a bit on the porous side – have allowed opponents fewer opportunities in the first place, so it could be much worse.

At the top of the graphic we can see that Luton have proven incredibly difficult to break down, with almost 13 shots soaked up for each goal conceded: over four more than the average. Bottom side Newport have allowed a similar number of attempts at their goal but conceded around twice as readily.

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:

Portsmouth‘s performances look even more impressive when we correct for shot quality, particularly in defence where they’re only allowing around three quarters of a goal’s worth of chances per game.

The current top three are all among the top five for chance creation, along with Luton who appear to be performing at a very similar level to the league leaders overall.

Accrington still look like a side who should be closer to fourth from the top than fourth from the bottom – could the solution to their problems be as simple as adding a more clinical finisher?

A cluster of four teams in the top left look to be in the most danger of relegation: the current bottom two of Newport and Notts County, plus Leyton Orient and Hartlepool are all creating far worse chances than they allow.