Liverpool defence. Statistical anomaly or impenetrable fortress?


Written by Jønathan Kahn. You can catch him on twitter @jkisthe1. Kahn has ranked as high as 105th on the All-Time FPL Manager list!

Since the 5-2 win at home to Everton Liverpool have secured an unbelievable 10 clean sheets in 12 games. This has led many that weren’t already doing so to double, or even triple up on their defence. But the question is, is this because the Liverpool defence is simply that good, or is there something else at work. Using data taken from Fantasy Football Scout we can assess this.

To do this there are some key stats we need to look at. Big Chances Conceded (that is to say a chance where the attacker would be expected to score) shots conceded in the box and errors leading to a chance. I will use these three metrics to assess the outcome.

If we begin with Big Chances Conceded the numbers certainly suggest some degree of solidity in the Liverpool backline. They have conceded just 12 Big Chances in this period (so just one per game on average), fewer than any side in the league. The next best is Manchester United with 13. By contrast, over the same period, Aston Villa have conceded 51 Big Chances. On this evidence, it’s not unreasonable to expect Liverpool to have the number of clean sheets they do, although even one big chance per game means we should be expecting them to concede once per game. Is this down to great goalkeeping, poor finishing or a combination of the two?

Next, let’s move onto Shots conceded in the Box. Again the numbers look good for Liverpool. They are once again the best in the league with 61 shots conceded in the box in this period, the next best is Manchester City with 64. Once again Aston Villa sit worst in this category with an incredible 147 shots conceded in the box. So again it’s not unreasonable to expect Liverpool to have a high number of clean sheets. Yet if we compare them to Manchester City who have conceded just three more shots in the box (and 26 outside compared to Liverpool’s 35) they have conceded 12 goals and registered five clean sheets. This is four times as many goals as Liverpool and half as many clean sheets. All this from three fewer shots in the box (and fewer shots overall, City conceded a chance every 12.7 minutes, compared with 11.8 for Liverpool). So, whilst it’s reasonable to expect a decent number of clean sheets from Liverpool, it seems a heck of disparity from Manchester City’s numbers. Again, have Liverpool been lucky, have City been unlucky, or is it both?

So we move on to the final measure, errors. We can assess this in two ways. Errors leading to chances and errors leading to goals. Here the reading isn’t quite as rosy. Liverpool have made 8 errors leading to chances a joint league-high with Leicester and Wolves. This suggests that the Liverpool defence can be gotten at and forced into mistakes with the right setup. At the other end of the scale Manchester United, Crystal Palace and Watford have all made just one error leading to a chance. Yet United and Watford sit on five clean sheets with 11 and 13 goals conceded respectively with Palace on two clean sheets and 14 conceded. This suggests there is a definite element of luck, or voodoo, or black magic, whatever you want to call it, on the Liverpool goal.

A quick glance at the errors leading to goals numbers bears this out. Liverpool sit on zero for this metric alongside Watford, whilst United and Palace both sit on two. Manchester City sit on two and one for these metrics.

So if we take Liverpool’s numbers as being normal then we can expect City and United to start catching them (and actually United have six clean sheets in their last eight) and maybe even Watford. But if we consider City and United to have the more normal numbers then it’s reasonable to suggest that Liverpool’s defence has to start conceding more goals soon. Was West Ham the start? It just doesn’t sound plausible for City to have half as many clean sheets and four times as many goals conceded as Liverpool from three more shots in the box conceded and fewer shots overall.


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