Comparing player rating systems as a metric for assessing individual performance in soccer

Area of Science:

• Sports Science
• Data Analytics
• Football Analytics

Background:

• Soccer player performance is often summarized by single-value ratings.
• Several prominent rating systems exist, including WhoScored, FotMob, and Sofascore.
• The comparability and underlying factors of these systems are not fully understood.

Purpose of the Study:

• To investigate the associations between soccer player performance metrics and ratings.
• To compare the influence of various metrics across three major rating systems: WhoScored, FotMob, and Sofascore.
• To assess the interchangeability and potential biases of these rating systems.

Main Methods:

• Utilized data from over 2,100 players across two seasons in top European leagues.
• Employed generalized linear mixed models to analyze the impact of 73 performance metrics on player ratings.
• Performed comparative analysis across WhoScored, FotMob, and Sofascore rating systems.

Main Results:

• Offensive metrics like shots on target, key passes, and successful take-ons significantly influenced all rating systems.
• Defensive metrics, such as clearances, had a smaller but consistent impact on ratings.
• Systematic differences were observed, with WhoScored ratings being significantly lower overall compared to FotMob and Sofascore.

Conclusions:

• Soccer rating systems capture distinct aspects of player performance and are not directly interchangeable.
• The findings highlight the need for careful consideration of rating system methodologies in scouting and player development.
• Further research is recommended to explore the utility of these systems in recruitment and talent identification, addressing transparency and potential biases.