Evaluating the Impact of Video Assistant Referee Implementation in Football: A Four-Season Analysis of Match Performance Trends

Resumen

This study aimed to examine the influence of the Video Assistant Referee (VAR) system on match performance indicators in professional football, specifically within the Turkish Super League. The objectives were two-fold: (i) to compare match variables such as yellow cards, red cards, goals, penalties, fouls, and offsides between seasons with and without VAR, and (ii) to analyze the evolution of these variables across four consecutive seasons following VAR implementation. A total of 2636 matches were analyzed, comprising 1224 matches played without VAR (2014–2018) and 1412 matches played with VAR (2018–2022). Match data were obtained from InStat Scout® and included key indicators directly associated with referee decisions. Statistical analyses included the Independent Sample T-Test to assess differences between the pre- and post-VAR periods, One-Way ANOVA with Tukey post hoc tests to examine seasonal trends post-VAR, and generalized linear models to identify the effects of VAR implementation on each performance variable. The results revealed significant reductions in fouls, yellow cards, and offsides (p < 0.001), and a significant increase in penalties awarded (p < 0.001) following the introduction of VAR. No statistically significant differences were found for red cards or goals. Furthermore, the number of fouls committed showed a consistent decline across each season after VAR implementation, suggesting a long-term behavioral adaptation by players. These findings underscore the lasting impact of VAR on the dynamics of professional football matches and highlight the need for players, coaches, and referees to accordingly adapt their strategies. This study contributes to the growing body of evidence supporting VAR’s role in improving decision accuracy, though its broader implications for game flow and player performance warrant further investigation.