What Is VAR? How Video Assistant Referee Technology Works

The Video Assistant Referee system represents the most significant technological intervention in football since the introduction of goal-line technology. Since its official incorporation into the Laws of the Game in 2018, VAR has fundamentally altered how matches are officiated, how goals are celebrated, and how fans experience the game.

What Is VAR?

VAR stands for Video Assistant Referee. It is a match-officiating system that allows a dedicated video referee to review decisions made by the on-field referee using video footage. The system was developed to address clear and obvious errors in four specific match-changing situations: goals, penalty decisions, direct red cards, and mistaken identity. The VAR is a qualified referee who sits in a video operation room (VOR) with access to multiple camera angles, including broadcast feeds, offside cameras, and specialised slow-motion replays. They are supported by an assistant VAR (AVAR) and a replay operator who manages the camera feeds. The VOR is typically located in the stadium or at a central hub, depending on the competition.

How VAR Works: The Review Process

The VAR process follows a structured protocol designed to minimise disruption while maximising accuracy. When a potential clear and obvious error occurs, the VAR begins a silent check by reviewing the footage from multiple angles. If the VAR determines that no clear error occurred, they communicate this to the on-field referee via headset, and play continues without interruption. If the VAR identifies a clear and obvious error, they recommend that the referee conducts an On-Field Review (OFR). The referee then signals a review by drawing a rectangular shape in the air and approaches the pitch-side monitor. At the monitor, the referee views the footage, sometimes from multiple angles, and makes the final decision. Crucially, the VAR can only recommend — the final decision always rests with the on-field referee.

What Can VAR Review?

VAR intervention is limited to four categories of decisions. First, goals and the attacking possession phase leading to them are reviewed, including any fouls, offsides, or handballs in the buildup. Second, penalty decisions are reviewed, including both penalties awarded and penalties not awarded when a potential offence occurred. Third, direct red cards — but not second yellow cards leading to a sending-off — are reviewed. Fourth, mistaken identity is corrected when the wrong player is carded. The concept of the attacking possession phase is particularly important. When a goal is scored, VAR can review whether an offence occurred in the immediate attacking phase that led to the goal. This typically covers the period from when the attacking team gained possession to when the goal was scored, though the exact duration varies by competition.

The VAR Protocol: On-Field Review vs. Silent Check

There are two types of VAR interventions: silent checks and on-field reviews. A silent check occurs when the VAR reviews an incident without interrupting play. The referee may delay play temporarily by raising an arm, but if the VAR confirms no clear error, play resumes without the referee visiting the monitor. Silent checks happen dozens of times per match and are invisible to most spectators. An on-field review is the more visible intervention. The referee stops play, signals the review, and walks to the pitch-side monitor. The referee may watch the incident at normal speed, slow motion, or frame by frame. For subjective decisions like fouls and handballs, normal speed is preferred to assess intent and intensity. For factual decisions like offside, slow motion and freeze frames are used to determine precise positioning.

Semi-Automated Offside Technology

One of the most significant developments in VAR technology is Semi-Automated Offside Technology (SAOT). Introduced by UEFA for the Champions League and adopted by FIFA for the 2022 World Cup, SAOT uses 12 dedicated tracking cameras mounted on stadium roofs to track 29 body data points per player, 50 times per second. The system also uses an inertial measurement unit (IMU) inside the match ball that detects when the ball is kicked. This allows the system to automatically determine the exact moment the ball is played and map the positions of all attacking players relative to the second-last defender. The result is a 3D animation that can be shown to fans in the stadium and on broadcasts, demonstrating exactly whether a player was offside.

Controversies and Criticism

Despite its intended purpose of reducing clear errors, VAR has been the subject of sustained criticism since its introduction. The primary complaints centre on several issues. First, decision consistency remains a major problem — similar incidents in different matches often produce different outcomes, undermining confidence in the system. Second, the subjective nature of many laws, particularly handball and foul thresholds, means that even with video review, decisions remain open to interpretation. Third, delays to the game are a persistent frustration. VAR checks, particularly complex offside reviews, can take over a minute, disrupting the rhythm and flow of matches. Fourth, the lack of transparency around VAR decision-making fuels suspicion. While some competitions now broadcast VAR audio, most do not, leaving fans and pundits guessing about what was discussed. The threshold for intervention — the clear and obvious error standard — is itself inconsistently applied, with some VAR officials intervening on marginal decisions while others let play continue.

VAR Around the World

Different competitions have implemented VAR with notable variations. The Premier League was a relatively late adopter, introducing VAR for the 2019-20 season after extensive testing. The English top flight has faced particular criticism for its implementation, with high thresholds for intervention leading to accusations that VAR is too passive. La Liga and Serie A have adopted more interventionist approaches, with VAR more willing to recommend on-field reviews. The Bundesliga is widely regarded as having one of the most efficient VAR implementations, with faster reviews and clearer communication. FIFA's World Cup implementations have been praised for their use of semi-automated offside and transparent communication of decisions to fans via stadium screens and broadcast graphics.

The Future of VAR

The evolution of VAR continues, with several reforms being considered or trialled. The introduction of a challenge system, similar to those used in tennis and cricket, has been proposed, giving managers a limited number of challenges per match. Stricter time limits for reviews would reduce delays and force faster decision-making. The broadcast of VAR audio to television audiences and stadium screens would increase transparency and help fans understand decisions. Semi-automated offside technology is expected to become standard across all major competitions, reducing the time required for offside reviews. Some have proposed expanding VAR's scope to include corners, throw-ins, and second yellow cards, though this would significantly increase the number of interruptions. The challenge for football's lawmakers is to harness technology's benefits while preserving the flow, emotion, and human element that makes the sport compelling.