Scatter graphics: Premier League, 31 Oct 2016
With ten rounds of matches having been played in the Premier League I thought it was time to revisit the scatter graphic templates and see how the top flight is shaping up. It’s worth flagging that at this early stage the relative difficulty of each club’s fixtures will definitely be influencing their performances, so please bear this in mind.
Each of the four graphics is explained briefly below but there’s a longer explanation here for the curious.
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).
Starting in the bottom right, Liverpool have been the most dominant team so far in raw shot terms, closely followed by Man City and Tottenham. Nearby are Man Utd: no longer their shot-shy selves from last season and are now right up there with the most frequent attackers.
There’s a real “no man’s land” in the middle of the graphic: clubs are steering clear of 13 shots per match as if they were superstitious.
In the unhappy top left, newly-promoted Burnley and Hull look to be spending the majority of the time on the back foot: creating a single-digit number of chances per game while allowing more than 20 in return. Sunderland look similarly wretched.
While it’s odd seeing Leicester in the “bad” quadrant, this could be explained by them having had a pretty tough start, facing four of the current top five plus Man Utd already.
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:
The four clubs in the bottom right – by no coincidence also the current top four in the league table – have mostly had things go their way up front so far.
It’s interesting to see from the top right that four of the five most wasteful finishers so far have created an above-average number of chances, particularly Man Utd and Tottenham.
Watford have looked quietly efficient, managing to score regularly from a relatively modest number of opportunities.
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:
Tottenham may be struggling to convert their chances but they lead the way defensively. Only three sides allow fewer shots and it’s taken an average of 19 attempts to breach their back line.
Only Burnley have soaked up a similar amount of punishment for each goal conceded but they’ve had over twice as many shots to deal with overall.
Wedged in the bottom left corner are Liverpool, whose defence has allowed the fewest shots of all so far but has also been the division’s leakiest.
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. FYI there may be some differences with expected goals values published by other bloggers, who have access to far more detailed data than I do:
So Man City and Liverpool look to be leading the way so far, creating over two goals’ worth of chances per match while allowing fewer than one in return.
When we were just treating all shots equally in the first graphic, Man Utd and Tottenham were sitting alongside them, but both are placed more modestly here. That suggests to me that the average quality of chances created by these two is lower, which might in turn explain their struggles to turn shots into goals so far.
In the opposite corner, Hull and Burnley remain the two clubs with the most concerning performances but now sit further apart than in the first graphic. The Clarets’ attack looks to be their more pressing concern, while for the Tigers it’s the defence that’s looked more worrying.