Scatter graphics: Premier League, 31 Dec 2017
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).
Five of the ‘big six’ clubs stand out as more dominant than the rest – the exception being Man Utd who are creating roughly 3 fewer shots per match and allowing roughly 3 more than their rivals’ average. Liverpool look to be the closest to runaway leaders Man City.
I mentioned before that Crystal Palace looked better than their results and they’re comfortably above average in raw shot terms.
Huddersfield look to be this season’s “safety first” team – creating little but allowing little in return.
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 it starts to go a bit wrong for Crystal Palace: despite the respectable number of shots they’ve taken they’ve been the worst finishers in the division, although a lot of this is the hangover from that awful start to the season. Newcastle and Southampton have had similar woes.
Meanwhile Man Utd are one of the sharpest finishers, which is helping them to keep pace with their goalscoring feats of their more productive rivals. Everton and Leicester have also been able to rely on some clinical finishing despite creating relatively few chances.
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:
Man Utd‘s defence – or perhaps just David De Gea’s heroics – are also helping to keep them competitive at the top of the table. Only Burnley are soaking up more shots for each goal conceded so far this season, which explains how they’ve been able to concede fewer goals than today’s opponents Liverpool despite allowing over twice as many attempts at their goal.
Only Stoke and Watford have absorbed fewer shots per goal conceded than the Reds, so it’s not that surprising to see them shelling out big money on a defender.
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:
Man City look far more dominant than the rest when we correct for shot quality – they’re creating around three times the quality of chances than they’re allowing, which is pretty insane.
While Man Utd look slightly closer to the rest of the chasing pack now, it’s surreal to see Crystal Palace so close behind them. On this evidence they look far likelier to move up the table than be mired in a relegation scrap.
Swansea look to be in the most trouble: they’ve created the worst chances overall and only a handful of sides have allowed more to be fired at their goal in return, so Carlos Carvalhal has a tough challenge ahead of him.
Huddersfield‘s defence now looks less impressive and it’s West Brom who take the title of “safety first” team – that plays into the Tony Pulis stereotype but it will be interesting to see how they shift under Alan Pardew.