Have you watched that YouTube video about Sheffield United’s relegation? The one in which Adolf Hitler is down in the bunker screaming about David Unsworth’s goal – the strike that sent his old club down. Well, the F?hrer is going to be even more furious when he hears what I have to say this week. I don’t suppose he much likes the Fink Tank to start off with.
This week Dr Henry Stott and Dr Ian Graham have been studying shots that hit the woodwork, prompted by a query from Fink Tank reader Andrew Sutton.
Let’s begin with the trade-off involved in hitting the woodwork. In his excellent book How To Score, Ken Bray discusses the aerodynamics of shots. Computer simulations show that a difference in shot speed of 2mph and angle of one degree is enough for an on-target shot to go off target from 20 yards out.
Controlling such small differences is very hard. Of course there is a way of making sure that you do not have to exercise such tight control – simply shoot at the centre of the goal rather than the corner. But there is a problem – if you do that it is more likely that the goalkeeper will make a save.
Using some exciting work that the Fink Tank has been undertaking with Castrol oil, it is possible to analyse the exact nature of the choice. Balls shot from 15 yards to the centre of the goal have a 12 per cent chance of going in, in the bottom corner a 70 per cent chance and 88 per cent if directed into the top corner.
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Now, shooting towards the centre gives you an extremely high chance of being on target, while if you shoot towards the top corner you may miss. So for each choice of shot you must take together these chances – the chance of being on target and the chance of an on-target shot going in. And this calculation shows that if you think your shot has a 30 per cent chance or more of making it on to the target, you are better off shooting for the corner than the centre of the goal.
In a nutshell, then, going for the sort of shot that hits the woodwork is often the correct judgment and hitting the woodwork is a bit of bad luck that is hard to control.
How often do you think teams hit the woodwork? It seems like all the time. In fact it is surprisingly rare. The home team hit the woodwork once every four matches, the away team once every five matches. The rarity is not actually that much of an eyebrow-raiser. The posts are thin.
Now let’s turn to Andrew’s questions – how much of an impact did the woodwork make last season. We performed a simple calculation and added woodwork shots to the scorelines, as if they were goals.
Manchester United would still have been champions. They were king of hitting post and bar, but mainly in games that they won anyway. Fascinatingly, Arsenal would have scored 13 points more if their woodwork efforts had counted. One explanation for their performance this season is that they did relatively poorly last season only because of the freakish luck of being deprived of points by posts and bar all the time.
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Finally, to poor old Sheffield United. If their woodwork shots had counted, they would not have gone down. It would have been goodnight Fulham instead. Sorry, Adolf.