Expected Goals and Real Goals – Telling the True Story

Expected Goals and Real Goals – Telling the True Story
December 27, 2017 Andrew Beasley

 

David Sumpter is a smart cookie. Professors usually are. By day he deals in applied mathematics, but he is also a Liverpool fan who has presented at the Opta Pro Forum. He is the author of ‘Soccermatics: Mathematical Adventures in the Beautiful Game‘, a book which is both enjoyable and fascinating. In short, if he talks about numbers in football, he is definitely worth listening to.

In this excellent recent article, David wrote about how the noise in a football result is only slightly smaller than the signal:

“The small number of goals means that matches are decided by narrow margins. The signal (the strongest team) is only slightly stronger than the noise (the fact that anything can happen). QED.”

The following graph from the article displays how the noise decreases with the more matches a team plays.

This analysis, which goes on to show how many points + or –  the PL teams would have now based on xG, is for Subscribers’ only.