I am delighted to report that we have a paper recently accepted in the European Journal of Operational Research exploring the impact of Covid-19 infection on player performance across top European football leagues.
COVID-19 infections represent a recurrent source of workplace absenteeism impacting labour productivity. Using a unique matched employee-employer dataset, we consider the effects of the virus on the performance of highly valuable employees when returning to work: professional footballers in the top five European leagues. This offers a window to study job scheduling and managerial decision-making.
We manually construct a matched dataset for 229 players who tested positive for COVID-19 in 66 clubs across the top 5 European Leagues (Premier League, Ligue 1, Bundesliga, Serie A and La Liga). There is natural variation in the timing of these infections. Positive cases were recorded from the 8th of March 2020 to 26th of April 2021, and our data cover performances in the 2019/2020 and 2020/2021 seasons.
Importantly, our dataset excludes false positives, goalkeepers, COVID positive players that transferred to or from leagues outside of the top 5 over our sample timeframe, youth/reserve players and players that were relegated or promoted with their club. We employ then apply a difference-in-differences estimator that compares the performance of infected players to a matched control group for game tasks that require physical exertion.
Our results suggest that per-minute performance is unaffected upon returning to play. This is likely due to effective management of minutes on the pitch. We carry out a battery of checks on the primary results to consider causal mechanisms outside of infection that could impact the results such as lockdown breaks, clusters within squads, and scheduling effects.
The findings carry an optimistic message and specifically speak to managers supervising physical labour. If appropriately managed, infected workers can return to past performance levels.
The full paper is available open access and free to download here.