Scatter graphics: Premier League, 27 Dec 2019

As we’re roughly at the halfway stage of the season, it feels worth updating 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).

Despite yet another defeat, Man City remain the most dominant side in shot terms having taken more than twice as many shots as they’ve faced and around eight more per game than the average side. Sheffield United matches see around 10 fewer shots on average than those involving Aston Villa, so it’s safe to say that these two sides are approaching their return to the Premier League in very different ways. Everton actually look pretty decent here but the next two graphs show how they’ve struggled to turn dominance into points.

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:

Watford’s finishing remains horrific – it’s taken them nearly twice as many attempts to score each goal than the average team, but I’d be surprised if their record doesn’t improve before the end of the season. Both Chelsea and Man Utd have converted their excess of shots into goals at a fairly pedestrian rate, while Liverpool, Leicester and Tottenham have been ruthless in front of goal. Spurs have taken over four and a half fewer shots than Frank Lampard’s side but are outscoring them so far.

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:

The defences of Liverpool, Sheffield United and Leicester stand out here, with all three restricting their opponents to few chances while also proving tough to breach. Everton have managed the first feat but not the second – along with Man City and Chelsea the few shots they do allow have found their way into their net with worrying regularity. Crystal Palace have allowed over five shots per game more than City yet have conceded fewer goals.

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:

Correcting for shot quality shows that it’s attack where Man City are setting themselves apart. Liverpool are their closest challengers and have a marginally better record at the back so far. Newcastle look to be the least creative side going forward by quite some distance while Aston Villa’s above-average attack is coming at the cost of a worryingly open defence. Everton look equipped to climb back up the table as their overall performances have looked comfortably above average in the data. Watford look a fair bit worse here than they did in the first chart, so maybe poor finishing isn’t their only problem.