Slow-motion VAR replays during football matches do not impact a referee’s decisions by making incidents appear more intentional, a new report claims.
UK psychologists say slow motion actually helps referees to better distinguish yellow card and red card incidents during football matches.
The controversial VAR, or ‘video assistant referee’ system had been a constant talking point in the UK since its introduction to the Premier League last August.
Fans and pundits alike criticised VAR for interrupting the flow of football matches with its real-time and slow-mo action replays, requiring the referee to pause play and often leave the pitch.
But by recruiting a sample of real professional football officials, researchers claim to have provided solid evidence that VAR actually helps make the right decision.
Football fans will be faced with the frustrations of the high-tech VAR system once again when the Premier League resumes on June 17.
‘I am a lifelong football fan who was in favour of VAR when it was introduced, but I did have a scientific concern about perception of slow-motion,’ lead author George Mather, a professor of vision sciences at the University of Lincoln, told MailOnline.
‘The study’s results gives me more confidence in VAR. I think it should definitely be kept as the best way to deal with critical decisions.’
The VAR system is used by more than 20 football associations in domestic leagues and cups worldwide, from the German Bundesliga, the MLS in North America and the A-League down under, as well as cup competitions.
The introduction of VAR followed years of complaints from players, managers and fans of the wrong decisions being made by the officials – including violent tackles going unpunished.
It was introduced to the Premier League for this season back in August and had since been a trigger for lively debates from TV pundits, before the season was halted by the coronavirus pandemic.
Slow-motion replays are used in the dreaded VAR reviews, but research into the referee’s perception of the replay raises question marks.
Previous research supports the idea that incidents viewed in slow-motion may appear more intentional, potentially biasing decision-making.
‘Slow motion replay can systematically increase judgments of intent because it gives viewers the false impression that the actor had more time to premeditate before acting,’ according to a 2016 research paper published in PLOS.
To learn more, Professor Mather and his colleague carried out a study to test whether professional football referees would show this bias when they made decisions using slow-motion playback compared to real-time playback.
The team recruited 80 elite English professional football officials from the first two tiers of English league football – the Premier League and the Championship.
Each participant watched video clips of match incidents and made decisions about how much contact was made, whether it was deliberate and what disciplinary sanction they would apply if they’d been reffing the match.
The 60 incidents in total, recorded from matches of professional European leagues, were either given as fouls, yellow-card offences or red-card offences by the on-field referee, with 20 clips in each category.
Incidents were played to the participants in both real-time and slow motion, which was played at x0.25 or quarter speed.
Participants had no knowledge of the incidents, playback speeds or disciplinary sanctions relating to each clip.
Three judgements were then made about each incident – extent of contact, degree of intent and disciplinary sanction.
The participants’ judgements of each of these three factors increased progressively in line with the severity of the incident, as judged by the on-field referee at the time.
The team also found no evidence that slow-motion biases refereeing decisions by making incidents appear more intentional.
Playback speed had an effect on decision-making, but the team did not find a consistent bias due to slow-motion.
In fact, slow-mo actually helped referees to distinguish between yellow-card incidents and red-card incidents, they said.
Slow-motion playback increased the distinction between moderate and severe offences and may actually aid decision-making rather than hinder it, they claim.
Watching a slow-mo playback of an incident before a real-time playback – another possible influencer of the severity of the ref's verdict – also made no difference on the final decision.
Professor Mather pointed out that all the incidents in the clips were of challenges for the ball and none of them contained hand-ball or offside offences.
This suggests their findings are relevant to decisions that affect bookings and sending-offs only.
The team also say their conclusions only apply to elite officials, as used in the experiments, who were 'highly trained and experienced' in making very specific technical judgements.
‘The question of whether other viewers such as TV football pundits or supporters are also immune to playback speed effects is open,’ they say.
VAR also ultimately relies on human judgement to come up with a final decision, according to one critique of the system, and the fine line between a yellow and red card offence is often blurry.
The research has been published in Royal Society Open Science.