Soccer: Is scoring goals a predictable Poissonian process?

¹  Westfälische Wilhelms Universität Münster, Institut für Physikalische Chemie - Corrensstr. 30, 48149 Münster, Germany, EU
²  Westfälische Wilhelms Universität Münster, Institut für Organische Chemie - Corrensstr. 40, 48149 Münster, Germany, EU

Corresponding author: andheuer@uni-muenster.de

Received: 26 October 2009
Accepted: 12 January 2010

Abstract

The non-scientific event of a soccer match is analysed on a strictly scientific level. The analysis is based on the recently introduced concept of a team fitness (Eur. Phys. J. B, 67 (2009) 445) and requires the use of finite-size scaling. A uniquely defined function is derived which quantitatively predicts the expected average outcome of a soccer match in terms of the fitness of both teams. It is checked whether temporary fitness fluctuations of a team hamper the predictability of a soccer match. To a very good approximation scoring goals during a match can be characterized as independent Poissonian processes with pre-determined expectation values. Minor correlations give rise to an increase of the number of draws. The non-Poissonian overall goal distribution is just a consequence of the fitness distribution among different teams. The limits of predictability of soccer matches are quantified. Our model-free classification of the underlying ingredients determining the outcome of soccer matches can be generalized to different types of sports events.