Pointless Statistics

 

am a stats man and many do have their place in football. I do follow the money ball theory and have read countless books on statistical analysis on football. But you can go too far with football, and as media outlets attempt to find the new thing they can end up inventing a statistic that is simply pointless.

Recently the BBC have created (or adopted) a statistic called “Expected Goals”. The idea being that it shows how many goals should have been scored against how many were scored.

This is pointless as all the matters is the goals actually scored.

Against Manchester United, Arsenal were expected to have scored 4.6 goals based on the chances. Manchester United 1.9 goals. Ignoring the fact that you can not score a decimal point of a goal, Manchester United scored 3 goals, and Arsenal 1.

Now I understand the stats surrounding chances created, shots on target, etc, but how the analysts decided Manchester United should only have scored 1.9 goals when all 3 of their chances were fairly routine is beyond me. It is a baffling statistic.

I have even seen a league table of expected goals – ie how the table would look if each match went to the expected goals rather than the actual. It is like those league tables which are altered to show results if shots that hit the woodwork went in. Or that Chelsea one from years ago which took out all goals by black players.

It is pointless.

At the end of the day, there is only one statistic that really matters, and that is the score at the end of the game.

Keenos

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One thought on “Pointless Statistics

  1. Vivek Arulnathan

    I like your blog mate but for someone who claims to have read countless books on statistical analysis in football, you clearly don’t seem to understand the reasoning behind expected goals and what it tries to convey.

    An xG of 1.9 does not mean the stats are saying Man Utd should have only scored 1.9 goals. If you score 3 goals from an xG of 1.9, it means you have finished tougher chances more efficiently. xG is an indication of quality of chance creation. It has its weaknesses such as not accounting for no.of defenders. But models are being developed to add this variable as well.

    So xG doesn’t represent how much the stats say you should score. It tells how well you are creating goal scoring chances. It is based on historical data of chance conversion rates to goals based on distance from goal. It is a highly relevant stat if understood correctly and not misinterpreted.

    Reply

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