The influence of the video assistant referee on the UEFA European Championship

Background Video Assistant Referee (VAR) as a high-tech aid was introduced into football in 2018 to enhance the officiating accuracy of referees. At the 2020 UEFA European Championship, VAR was used for the first time. This study aims to investigate the impact of VAR on the UEFA European Championship. Methods The sample includes all matches of EURO 2016 (without VAR, n = 51) and EURO 2020 (with VAR, n = 51), in a total of 102 matches. For each game, nine VAR-related variables were recorded: goals, penalties, red cards, yellow cards, fouls, offsides, first-half game time, second-half game time and total game time. The tournaments pre and post the introduction of VAR were compared using a Mann-Whitney U test. Results The results of this study revealed that the introduction of VAR led to a significant increase in the first-half match time (Z = 2.52, p = 0.012, ES = 0.13), the second-half match time (Z = 2.80, p = 0.005, ES = 0.16), total game time (Z = 3.74, p < 0.001, ES = 0.28) and the number of goals (Z = 2.25, p = 0.024, ES = 0.10), whereas a significant decrease in yellow cards (Z=-2.55, p = 0.011, ES = 0.13) was observed. Conclusions The findings of this study may have practical implications for optimizing VAR-related implementation regulations and the referee's officiating strategies at the UEFA European Championship competitions.