New rules, new game? The effects of the away goals rule removal and video assistant referee adoption on game dynamics in UEFA Champions League ties

This study investigates the impact of two recent rule changes in European soccer: the abolition of the away goals rule (AGR) and the introduction of the Video Assistant Referee (VAR) system. Specifically, it examines how these changes affect game dynamics, focusing on playing style indicators and disciplinary outcomes within the UEFA Champions League. We collect data on 1244 two-legged ties (2488 individual matches), spanning the seasons from the start of 2000/01 to the play-off stage of 2023/24. By analyzing the data at both the aggregate tie and individual leg levels and controlling for an extensive array of confounding variables, we challenge UEFA’s rationale for discontinuing the AGR. Contrary to UEFA’s justification for its removal, our findings reveal that the AGR promotes offensive rather than defensive play. Our findings regarding the VAR accord with the predominant view in the literature: less referee bias against away teams and increased aversion to risky tackles, hence, fewer disciplinary infractions. Given that the ties played under the AGR are found to be more competitive and thus more entertaining, our key policy implication is that UEFA should consider reinstating the AGR. Our results also suggest that the VAR should remain in place as it stimulates fairness and rule-abiding play.