Prospect theory and psychological factors in football: Effects of the video assistant referee on penalty conversion rates in the German Bundesliga

The increasing integration of technological aids, such as the video assistant referee (VAR), is fundamentally transforming decision-making processes in professional football, especially influencing critical match moments. Penalty kicks, characterised by technical simplicity but intense psychological pressure, may be particularly affected by delays caused by VAR reviews. An analysis of 737 penalty kicks in the German Bundesliga and second Bundesliga (2019-2023) reveals that penalties confirmed following VAR interventions show significantly lower conversion rates. This impact is especially pronounced during the early stages of matches, suggesting prolonged delays disrupt players' established pre-performance routines and heighten psychological stress, which aligns with prospect theory's insights on decision-making under uncertainty. Thus, these insights emphasise how technological innovations enhance officiating accuracy and introduce new psychological demands on athletes at the same time.